ORCID Profile
0000-0002-4662-0227
Current Organisation
Macquarie University
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Ethology and Sociobiology | Zoology | Animal Behaviour | Animal Neurobiology | Ecology | Vertebrate Biology | Behavioural Ecology
Expanding Knowledge in the Biological Sciences | Expanding Knowledge in the Environmental Sciences | Expanding Knowledge in Psychology and Cognitive Sciences | Flora, Fauna and Biodiversity at Regional or Larger Scales |
Publisher: The Royal Society
Date: 04-2018
DOI: 10.1098/RSOS.180197
Abstract: Invasive species must deal with novel challenges, both from the alien environment and from pressures arising from range expansion per se (e.g. spatial sorting). Those conditions can create geographical variation in behaviour across the invaded range, as has been documented across regions of Australia invaded by cane toads range-edge toads are more exploratory and willing to take risks than are conspecifics from the range-core. That behavioural ergence might be a response to range expansion and invasion per se , or to the different environments encountered. Climate differs across the cane toads' invasion range from the wet tropics of Queensland to the seasonally dry climates of northwestern Western Australia. The different thermal and hydric regimes may affect behavioural traits via phenotypic plasticity or through natural selection. We cannot tease apart the effects of range expansion versus climate in an expanding population but can do so in a site where the colonizing species was simultaneously released in all suitable areas, thus removing any subsequent phase of range expansion. Cane toads were introduced to Hawai'i in 1932 and thence to Australia in 1935. Toads were released in all major sugarcane-growing areas in Hawai'i within a 12-month period. Hence, Hawai'ian cane toads provide an opportunity to examine geographical ergence in behavioural traits in a climatically erse region (each island has both wet and dry sides) in the absence of range expansion subsequent to release. We conducted laboratory-based behavioural trials testing exploration, risk-taking and response to novelty using field-caught toads from the wet and dry sides of two Hawai'ian islands (Oahu and Hawai'i). Toads from the dry side of Oahu had a higher propensity to take risks than did toads from the dry side of Hawai'i. Toads from Oahu were also more exploratory than were conspecifics from the island of Hawai'i. However, toads from wet versus dry climates were similar in all behaviours that we scored, suggesting that founder effects, genetic drift, or developmentally plastic responses to ecological factors other than climate may have driven behavioural ergence between islands.
Publisher: Springer Science and Business Media LLC
Date: 14-03-2023
Publisher: The Royal Society
Date: 17-10-2012
Abstract: Spatial cognition is predicted to be a fundamental component of fitness in many lizard species, and yet some studies suggest that it is relatively slow and inflexible. However, such claims are based on work conducted using experimental designs or in artificial contexts that may underestimate their cognitive abilities. We used a biologically realistic experimental procedure (using simulated predatory attacks) to study spatial learning and its flexibility in the lizard Eul rus quoyii in semi-natural outdoor enclosures under similar conditions to those experienced by lizards in the wild. To evaluate the flexibility of spatial learning, we conducted a reversal spatial-learning task in which positive and negative reinforcements of learnt spatial stimuli were switched. Nineteen (32%) male lizards learnt both tasks within 10 days (spatial task mean: 8.16 ± 0.69 (s.e.) and reversal spatial task mean: 10.74 ± 0.98 (s.e.) trials). We demonstrate that E. quoyii are capable of flexible spatial learning and suggest that future studies focus on a range of lizard species which differ in phylogeny and/or ecology, using biologically relevant cognitive tasks, in an effort to bridge the cognitive ide between ecto- and endotherms.
Publisher: Herpetologists League
Date: 12-2009
DOI: 10.1655/08-027.1
Publisher: Herpetologists League
Date: 12-2003
DOI: 10.1655/02-33
Publisher: Wiley
Date: 12-2017
DOI: 10.1002/JEZ.2145
Publisher: Springer Science and Business Media LLC
Date: 22-12-2006
Publisher: Springer Science and Business Media LLC
Date: 26-05-2015
Publisher: American Association for the Advancement of Science (AAAS)
Date: 13-05-2022
Abstract: Conspicuous social and sexual signals are predicted to experience pronounced character release when natural selection via predation is relaxed. However, we have few good ex les of this phenomenon in the wild and none in species with dynamic color change. Here, we show that Jackson’s chameleons inadvertently introduced from Kenya to Hawaii (Oahu), where there are no coevolved, native lizard predators, experienced pronounced character release of color signals. Hawaiian chameleons displayed more conspicuous social color signals than Kenyan chameleons during male contests and courtship, were less cryptic in response to bird and snake predators, and showed greater change between display and antipredator color states. Hawaiian chameleon display colors were also more conspicuous in their local than ancestral habitats, consistent with local adaptation of social signals. These results demonstrate that relaxed predation pressure can result in character release of dynamic social signals in introduced species experiencing strong sexual selection.
Publisher: Cambridge University Press (CUP)
Date: 25-09-2009
Publisher: Elsevier BV
Date: 08-2006
Publisher: Oxford University Press (OUP)
Date: 23-09-2023
Publisher: The Royal Society
Date: 10-2017
DOI: 10.1098/RSOS.170789
Abstract: In iduals at the leading edge of expanding biological invasions often show distinctive phenotypic traits, in ways that enhance their ability to disperse rapidly and to function effectively in novel environments. Cane toads ( Rhinella marina ) at the invasion front in Australia exhibit shifts in morphology, physiology and behaviour (directionality of dispersal, boldness, risk-taking). We took a common-garden approach, raising toads from range-core and range-edge populations in captivity, to see if the behavioural ergences observed in wild-caught toads are also evident in common-garden offspring. Captive-raised toads from the invasion vanguard population were more exploratory and bolder (more prone to ‘risky’ behaviours) than toads from the range core, which suggests that these are evolved, genetic traits. Our study highlights the importance of behaviour as being potentially adaptive in invasive populations and adds these behavioural traits to the increasing list of phenotypic traits that have evolved rapidly during the toads' 80-year spread through tropical Australia.
Publisher: CSIRO Publishing
Date: 21-11-2022
DOI: 10.1071/ZO22039
Abstract: Parasite load can vary with seasonality, but this is rarely quantified. The garden skink (L ropholis guichenoti) is host to multiple species of endoparasite. To measure seasonal effects of parasite transmission we established three captive groups of wild-caught in iduals in which 2 of 16 in iduals (12.5%) were initially infected with nematodes. We collected three faecal s les from each lizard, a s le at the beginning and at the end of the non-activity season and at the end of the following activity season. We measured parasite load (ascarid group) by counting parasite eggs per gram of faeces using a microscope. We found that parasite load was significantly higher in the activity season than in the non-activity season. The prevalence of parasites increased from 15.9% in the non-activity season to 72.5% in the activity season. The activity season is characterised by greater host activity and warmer ambient temperatures, which promote parasite egg survival in the environment as well as egg development. Taken together, this facilitates parasite transmission and could ultimately explain the higher parasite load during the activity season.
Publisher: Wiley
Date: 12-04-2021
DOI: 10.1111/AEC.13030
Abstract: Understanding the evolution of vertebrate sociality requires comparative data on social associations across the vertebrate phylogeny. In the case of group‐living lizards (i.e. species that live in stable social aggregations often associated with a shared resource), most work has focused on the Egerniinae in Australia, resulting in a taxonomic and geographic skew to our understanding of reptile sociality. The African cordylid lizards (Cordylidae) are also a promising system to study the evolution of sociality because grouping behaviour varies across the clade. Here, we studied the conspecific grouping behaviour of two crag lizards, Pseudocordylus langi and P. melanotus subviridis that occur at high elevations in the Maloti‐Drakensberg Mountains of South Africa. To better understand their social organisation and mating system, we also present data on their spatial distribution, sexual dimorphism, and bite force. Both Pseudocordylus spp. were sexually dimorphic in morphology (males had larger heads than females of similar body size), colouration (males were more colourful) and female P. langi had a weaker bite force than males. Both P. langi and P. m. subviridis were associated with rocky habitat on the mountainside (e.g. cliffs, rock buttresses, and rock outcrops) and both were spaced apart and rarely in groups (79% of P. langi and 90% of P. m. subviridis were observed alone). Based on our findings, we hypothesise that both Pseudocordylus spp. have a territorial social structure and a polygynous mating system. This novel natural history information about crag lizards supports the assertion that Cordylidae is another model system for examining the evolution of sociality.
Publisher: The Royal Society
Date: 07-2014
Abstract: Evidence of social learning, whereby the actions of an animal facilitate the acquisition of new information by another, is taxonomically biased towards mammals, especially primates, and birds. However, social learning need not be limited to group-living animals because species with less interaction can still benefit from learning about potential predators, food sources, rivals and mates. We trained male skinks ( Eul rus quoyii ), a mostly solitary lizard from eastern Australia, in a two-step foraging task. Lizards belonging to ‘young’ and ‘old’ age classes were presented with a novel instrumental task (displacing a lid) and an association task (reward under blue lid). We did not find evidence for age-dependent learning of the instrumental task however, young males in the presence of a demonstrator learnt the association task faster than young males without a demonstrator, whereas old males in both treatments had similar success rates. We present the first evidence of age-dependent social learning in a lizard and suggest that the use of social information for learning may be more widespread than previously believed.
Publisher: Oxford University Press (OUP)
Date: 19-08-2021
Abstract: The ability to produce viable offspring without recently mating, either through sperm storage or parthenogenesis, can provide fitness advantages under a suite of challenging ecological scenarios. Using genetic analysis, we demonstrate that 3 wild-caught female Tree Skinks (Egernia striolata) reproduced in captivity with no access to males for over a year, and that this is best explained by sperm storage. To the best of our knowledge, this is the first time female sperm storage has been documented in any monogamous family-living reptile, including social Australian egerniine skinks (from the subfamily Egerniinae). Furthermore, by using paternal reconstruction of genotypes we show that captive-born offspring produced by the same females in the preceding year, presumably without sperm storage, were sired by different males. We qualitatively compared aspects of these females’ mates and offspring between years. The parents of each litter were unrelated, but paternal and offspring genotypes from litters resulting from stored sperm were more heterozygous than those inferred to be from recent matings. Family-living egerniine skinks generally have low rates of multiple paternity, yet our study suggests that female sperm storage, potentially from outside social partners, offers the real possibility of benefits. Possible benefits include increasing genetic compatibility of mates and avoiding inbreeding depression via cryptic female choice. Sperm storage in Tree Skinks, a family-living lizard with a monogamous mating system, suggests that females may bet-hedge through extra-pair copulation with more heterozygous males, reinforcing the idea that females could have more control on reproductive outcomes than previously thought.
Publisher: Springer Science and Business Media LLC
Date: 02-06-2018
DOI: 10.1007/S10071-018-1194-Y
Abstract: A key question in cognition is whether animals that are proficient in a specific cognitive domain (domain specific hypothesis), such as spatial learning, are also proficient in other domains (domain general hypothesis) or whether there is a trade-off. Studies testing among these hypotheses are biased towards mammals and birds. To understand constraints on the evolution of cognition more generally, we need broader taxonomic and phylogenetic coverage. We used Australian eastern water skinks (Eul rus quoyii) with known spatial learning ability in three additional tasks: an instrumental and two discrimination tasks. Under domain specific learning we predicted that lizards that were good at spatial learning would perform less well in the discrimination tasks. Conversely, we predicted that lizards that did not meet our criterion for spatial learning would likewise perform better in discrimination tasks. Lizards with domain general learning should perform approximately equally well (or poorly) in these tasks. Lizards classified as spatial learners performed no differently to non-spatial learners in both the instrumental and discrimination learning tasks. Nevertheless, lizards were proficient in all tasks. Our results reveal two patterns: domain general learning in spatial learners and domain specific learning in non-spatial learners. We suggest that delineating learning into domain general and domain specific may be overly simplistic and we need to instead focus on in idual variation in learning ability, which ultimately, is likely to play a key role in fitness. These results, in combination with previously published work on this species, suggests that this species has behavioral flexibility because they are competent across multiple cognitive domains and are capable of reversal learning.
Publisher: Springer Science and Business Media LLC
Date: 07-06-2018
Publisher: Oxford University Press (OUP)
Date: 2011
Publisher: Wiley
Date: 08-2002
Publisher: Elsevier BV
Date: 05-2019
Publisher: Society for the Study of Amphibians and Reptiles
Date: 09-2007
Publisher: Springer Science and Business Media LLC
Date: 02-06-2022
DOI: 10.1038/S41597-022-01364-9
Abstract: Trait databases have become important resources for large-scale comparative studies in ecology and evolution. Here we introduce the AnimalTraits database, a curated database of body mass, metabolic rate and brain size, in standardised units, for terrestrial animals. The database has broad taxonomic breadth, including tetrapods, arthropods, molluscs and annelids from almost 2000 species and 1000 genera. All data recorded in the database are sourced from their original empirical publication, and the original metrics and measurements are included with each record. This allows for subsequent data transformations as required. We have included rich metadata to allow users to filter the dataset. The additional R scripts we provide will assist researchers with aggregating standardised observations into species-level trait values. Our goals are to provide this resource without restrictions, to keep the AnimalTraits database current, and to grow the number of relevant traits in the future.
Publisher: Society for the Study of Amphibians and Reptiles
Date: 09-2005
DOI: 10.1670/55-05N.1
Publisher: Springer Science and Business Media LLC
Date: 04-11-1999
Publisher: Wiley
Date: 06-2003
Publisher: Springer Science and Business Media LLC
Date: 09-05-2019
Publisher: The Royal Society
Date: 07-05-2014
Abstract: Understanding in idual differences in cognitive performance is a major challenge to animal behaviour and cognition studies. We used the Eastern water skink ( Eul rus quoyii ) to examine associations between exploration, boldness and in idual variability in spatial learning, a dimension of lizard cognition with important bearing on fitness. We show that males perform better than females in a biologically relevant spatial learning task. This is the first evidence for sex differences in learning in a reptile, and we argue that it is probably owing to sex-specific selective pressures that may be widespread in lizards. Across the sexes, we found a clear association between boldness after a simulated predatory attack and the probability of learning the spatial task. In contrast to previous studies, we found a nonlinear association between boldness and learning: both ‘bold’ and ‘shy’ behavioural types were more successful learners than intermediate males. Our results do not fit with recent predictions suggesting that in idual differences in learning may be linked with behavioural types via high–low-risk/reward trade-offs. We suggest the possibility that differences in spatial cognitive performance may arise in lizards as a consequence of the distinct environmental variability and complexity experienced by in iduals as a result of their sex and social tactics.
Publisher: Elsevier BV
Date: 10-2022
DOI: 10.1016/J.BEPROC.2022.104749
Abstract: To make decisions, animals gather information from the environment in order to avoid costs (e.g., reduced survival) and increase benefits (e.g., foraging success). When time is limited or information is insufficient, most animals face a speed-accuracy trade-off (SAT) - they have to balance the benefits of making quick decisions against the costs of inaccurate decisions. Here, we investigated the relationship between decision accuracy and decision speed in gidgee skinks (Egernia stokesii) performing a food-based spontaneous quantity discrimination task. Rather than a SAT we found a speed-accuracy alignment lizards made decisions that were fast and accurate, rather than inaccurate. Furthermore, we found only within-, but no between-in idual differences in decision making indicating behavioural plasticity in the absence of in idual decision styles. Finally, latency to choice was highly repeatable, more so than choice accuracy. Previous work has shown that learning, the costs of a bad decision and task difficulty frequently result in SATs. The lack of a SAT in our lizards might be a direct consequence of our simple testing methodology which prevented learning by not allowing lizards to consume the chosen quantity. To fully understand how SATs develop, different methodologies that control the costs and benefits of decisions should be compared.
Publisher: Frontiers Media SA
Date: 29-05-2018
Publisher: Oxford University Press (OUP)
Date: 30-05-2022
DOI: 10.1093/BIOLINNEAN/BLAC044
Abstract: Conspicuously coloured signals may evolve via sexual selection to be ornaments or armaments, thereby conferring a fitness advantage to their bearer. Conversely, conspicuous colours may also evolve under natural selection as either aposematic signals or deimatic displays that deter attacks from predators. While conspicuous colour patches may evolve for one purpose (e.g. quality indicators), they may later be co-opted for another (e.g. anti-predator defence). Phrynocephalus mystaceus is a cryptic agamid lizard with flaps in both sexes that when folded against the head are inconspicuous, but when deployed are predicted to be highly conspicuous and to increase the appearance of body size. We tested whether head flaps play a role in social signalling via courtship or as status signals during contests in both sexes. We also tested whether the head flaps have an anti-predator function by simulating predatory encounters. Head flaps were never deployed in courtship or during contests and, therefore, are unlikely to be under sexual selection. However, head flaps and their deployment during simulated predatory encounters were consistent with the predictions associated with deimatic display theory. First, head flaps were similar in form and function between sexes. Second, they were highly conspicuous to both avian and snake predators. Third, there was a rapid transition from crypsis to conspicuousness when they deployed their head flaps during a late stage of predation, the subjugation phase, consistent with an ambush. Confirmation of the deimatic display hypothesis will require future testing of receiver responses.
Publisher: Informa UK Limited
Date: 12-2000
Publisher: Springer Science and Business Media LLC
Date: 30-07-2015
Publisher: Elsevier BV
Date: 05-2004
Publisher: Informa UK Limited
Date: 10-2003
Publisher: Wiley
Date: 19-10-2021
DOI: 10.1111/BRV.12658
Publisher: Oxford University Press (OUP)
Date: 14-07-2015
DOI: 10.1111/BIJ.12610
Publisher: Cambridge University Press
Date: 30-07-2018
Publisher: The Royal Society
Date: 11-2017
Abstract: In iduals at the leading edge of a biological invasion constantly encounter novel environments. These pioneers may benefit from increased social attraction, because low population densities reduce competition and risks of pathogen transfer, and increase benefits of information transfer. In standardized trials, cane toads ( Rhinella marina ) from invasion-front populations approached conspecifics more often, and spent more time close to them, than did conspecifics from high-density, long-colonized populations.
Publisher: Elsevier BV
Date: 02-2016
DOI: 10.1016/J.JEP.2015.12.024
Abstract: The use of animals and plants as traditional remedies for both medical afflictions and social or cultural issues (symbolism) has a long history in South Africa and a reasonably large proportion of the population will consult a traditional healer during their life-time. Compared to plants, the use of animal parts in traditional medicine and folklore is poorly documented. We interviewed 32 traders from South Africa's largest traditional medicine market, the Faraday Street market in Johannesburg, of which only 20 consented to supplying some species use information. Traders are particularly protective of the medicinal properties of their wares. Given the sensitive nature of this information (12 traders declined to be interviewed), we were only able to gather data on their perceived uses and no data on dosages, efficacy, or in idual turn-over of products. We assessed the trade of animal parts from the perspective of consumer needs by analysing use-categories (e.g. headaches, strokes, skin problems, bad luck, etc.) and the degree of informant consensus in the selection of fauna to treat certain conditions. We documented 301 uses for animal parts from 52 species and 18 'morphospecies' that we allocated to 122 broad-use categories. Overall, reptiles and mammals were the most frequently used taxa in traditional medicine and some species had multiple uses (i.e., appeared in multiple use-categories) including crocodiles, lizards generally, chameleons, striped polecats, elephants and jackals. Animals were mostly used for 'strength' (physical or overcoming fear), but also as love charms, warding off bad luck or bad spirits or improving one's luck. Only 36% of our categories were medicinal (e.g., headaches, skin problems, swollen feet, etc.). We also found a high rate of non-disclosure of uses per species (a mean 86% of traders did not reveal information on the use of a species), and a variable degree of consensus between the traders on what particular species are actually used for. We suggest that traditional medicine markets provide a unique opportunity to gauge the health and symbolic or personal issues representative of a large sector of society. What's more, we recommend that researchers be more mindful in the way that use information is reported. We also highlight the potentially serious threat of traditional medicine to species that may be particularly vulnerable by virtue of their restricted distribution or predictable behaviour.
Publisher: S. Karger AG
Date: 2022
DOI: 10.1159/000521750
Abstract: The habenula is a small structure in the brain that acts as a relay station for neural information, helping to modulate behaviour in response to variable and unpredictable stimuli. Broadly, it is evolutionarily conserved in structure and connectivity across vertebrates and is the most prominent bilaterally asymmetric structure in the brain. Nonetheless, comparative evolutionary studies of the habenula are virtually non-existent. Here, we examine the volumes of the medial and lateral habenular subregions, in both hemispheres, across a group of Australian agamid lizards in the genus i Ctenophorus /i . In males, we found bilaterally asymmetrical selection on the lateral habenula to become smaller with increasing intensity of sexual selection, possibly as a mechanism to increase aggressive responses. In females, we found bilaterally symmetrical selection on both the medial and lateral subregions to become smaller with increasing sexual selection. This is consistent with sexual selection increasing motivation to reproduce and the habenula’s well-characterized role in controlling and modifying responses to rewarding stimuli. However, as there are currently no studies addressing habenular function in reptiles, it is difficult to draw more precise conclusions. As has happened recently in biomedical neuroscience, it is time for the habenula to receive greater attention in evolutionary neuroscience.
Publisher: eLife Sciences Publications, Ltd
Date: 07-02-2017
DOI: 10.7554/ELIFE.22089
Abstract: Mimicry complexes typically consist of multiple species that deter predators using similar anti-predatory signals. Mimics in these complexes are assumed to vary in their level of defence from highly defended through to moderately defended, or not defended at all. Here, we report a new multi-order mimicry complex that includes at least 140 different putative mimics from four arthropod orders including ants, wasps, bugs, tree hoppers and spiders. All members of this mimicry complex are characterised by a conspicuous golden body and an ant Gestalt, but vary substantially in their defensive traits. However, they were similarly effective at deterring predators - even mildly defended mimics were rarely eaten by a community of invertebrate and vertebrate predators both in the wild and during staged trials. We propose that despite the predominance of less defended mimics the three predatory guilds avoid the mimics because of the additive influence of the various defensive traits.
Publisher: Frontiers Media SA
Date: 30-06-2020
Publisher: Informa UK Limited
Date: 12-2005
Publisher: Public Library of Science (PLoS)
Date: 11-07-2012
Publisher: Springer Science and Business Media LLC
Date: 06-2020
Publisher: Springer Science and Business Media LLC
Date: 20-09-2020
Publisher: Brill
Date: 08-1999
Publisher: Wiley
Date: 26-12-2021
DOI: 10.1111/JEB.13752
Abstract: Sexual selection shapes the adaptive landscape in complex ways that lead to trait integration. Much of our understanding of selection comes from studies of morphological traits. However, few studies attempt to quantify the form and direction of selection on performance even though it is predicted to be a more direct target of selection in nature. We measured sexual selection on performance traits (bite force, sprint speed and endurance) in an Australian lizard, the Eastern water skink ( Eul rus quoyii ). We first staged 123 contests between size‐matched males to investigate whether performance traits were important in determining contest outcome. In a second experiment, we established six breeding populations in large replicate semi‐natural enclosures to estimate whether performance traits predicted reproductive success. Our results show that none of the performance measures were important in predicting contest outcome and were not generally strong predictors of reproductive success. However, our analyses suggest a complex fitness landscape driven by males adopting different alternative reproductive tactics (ARTs). We provide a rare test of the role performance plays in sexual selection and highlight the need to test common assumptions regarding the link between maximal performance and fitness. Our results suggest that performance traits may not necessarily be direct targets of sexual selection, but rather indirect targets through their integration with morphological and/or behavioural traits, highlighting a need for more explicit tests of the predicted links between performance and fitness.
Publisher: Springer Science and Business Media LLC
Date: 28-05-2018
Publisher: Springer International Publishing
Date: 2016
Publisher: Springer Science and Business Media LLC
Date: 09-05-2012
DOI: 10.1007/S10071-012-0503-0
Abstract: In subterranean species where excavation is energetically expensive, efficient spatial navigation is vital to reducing the costs of locating important resources such as food and mates. While spatial navigational ability is positively correlated with sociality in subterranean mammals, we have a less clear understanding of the role of habitat complexity on navigational ability. We tested spatial navigational ability and memory in 12-18-month captive Natal mole-rats (Cryptomys hottentotus natalensis) maintained in a simple environment with no environmental enrichment and newly captured wild in iduals from natural, complex burrow systems. In maze trials, mole-rats captured freshly from the wild made significantly fewer navigational errors, were more likely to successfully navigate the maze, travelled shorter distances and as a consequence, completed the maze in less time. Male mole-rats from both experimental treatments were more likely to complete the maze than females. Memory retention of the maze was tested on day two, seven, 30 and 60, respectively. The results were variable, although both groups showed a significant memory retention 60 days after testing. Our results highlight the potential importance of the environment (microhabitat complexity) on spatial cognitive performance in mole-rats.
Publisher: Springer Science and Business Media LLC
Date: 06-07-2019
Publisher: American Society of Ichthyologists and Herpetologists (ASIH)
Date: 2000
Publisher: Informa UK Limited
Date: 03-07-2019
Publisher: JSTOR
Date: 06-1993
DOI: 10.2307/3672068
Publisher: Springer Science and Business Media LLC
Date: 14-10-2021
Publisher: Springer Science and Business Media LLC
Date: 06-02-2022
DOI: 10.1007/S10071-022-01603-X
Abstract: One of the most widely studied abilities in lizards is discrimination learning. The protocols used to test lizards are often novel or adapted from other taxa without proper validation. We need to ensure that tests of discrimination learning are appropriate and properly applied in lizards so that robust inferences can be made about cognitive ability. Here, we present a new protocol for testing lizard discrimination learning that incorporates a target training procedure, uses many daily trials for efficiency and reinforcement, and has a robust, validated, learning criterion. We trained lizards to touch a cue card using operant conditioning and tested lizards separately on a colour, and pattern discrimination test. Lizards successfully learnt to touch a cue card and to discriminate between light and dark blue but had issues discriminating the patterns. After modifying the test procedure, some lizards reached criterion, revealing possible issues with stimulus processing and interference of generalisation. Here, we describe a protocol for operant conditioning and two-choice discrimination learning in lizards with a robust learning criterion that can help researcher better design future studies on discrimination learning in lizards.
Publisher: Magnolia Press
Date: 16-07-2015
DOI: 10.11646/ZOOTAXA.3986.2.2
Abstract: We describe a new species of flat lizard (Platysaurus attenboroughi sp. nov.) from the Richtersveld of the Northern Cape Province of South Africa and the Fish River Canyon region of southern Namibia. This species was formerly confused with P. capensis from the Kamiesberg region of Namaqualand, South Africa. Genetic analysis based on one mtDNA and two nDNA loci found Platysaurus attenboroughi sp. nov. to be genetically ergent from P. capensis and these species can also be differentiated by a number of scalation characters, coloration and their allopatric distributions. To stabilize the taxonomy the type locality of Platysaurus capensis A. Smith 1844 is restricted to the Kamiesberg region, Namaqualand, Northern Cape Province, South Africa.
Publisher: CSIRO Publishing
Date: 23-08-2021
DOI: 10.1071/RD21031
Abstract: Assisted reproductive technologies for population and genetic management for threatened herpetofauna have grown substantially in the past decade. Here we describe experiments to optimise sperm cryopreservation in a model squamate, the eastern water skink Eul rus quoyii. Small, concentrated volumes of highly motile spermatozoa were reliably collected from adult male E. quoyii by non-lethal ventral massage. S les were used to: (1) test whether protein-rich diluents, namely Beltsville poultry semen extender (BPSE) and TES and Tris (TEST) yolk buffer (TYB), improve post-thaw quality metrics compared with Dulbecco’s phosphate-buffered saline (DPBS) and (2) compare the efficacy of these diluents in combination with either 1.35 M glycerol or 1.35 M dimethyl sulfoxide (DMSO) at two freezing rates, fast (approximately –20°C min−1) versus slow (–6°C min−1). Glycerol and DMSO performed equally well in preserving spermatozoa under slow freezing rates. Under these conditions, the use of the complex diluents BPSE and TYB significantly improved post-thaw total motility compared with DPBS. Complex interactions occurred between cryodiluent type, cryoprotectant and freezing rate when testing fast versus slow freezing rates among treatment groups. Under slow freezing rates, DMSO was better at preserving membrane integrity and motility, regardless of diluent type, but successful fast freezing required complex diluents to support motility and membrane integrity, which has implications for implementation in a field setting.
Publisher: Elsevier BV
Date: 06-2021
Publisher: CSIRO Publishing
Date: 2018
DOI: 10.1071/RDV31N1AB109
Abstract: Australia has a rich ersity and high endemism (93%) of reptilian species, the largest family being Scincidae (252 species), yet there continues to be a paucity of reports for gamete cryopreservation in reptilians (Clulow and Clulow 2016 Reprod. Fertil. Dev. 28, 1116-1132, DOI: 10.1071/RD15466). The goal of this study was to collect sperm from a locally abundant skink species (Eul rus quoyii Eastern water skink) to examine sperm sensitivity to cryopreservation. Wild-caught males (n=50 snout-vent length=103-126mm) were held in seminatural conditions for the duration of the study. Semen was collected during the breeding season (September-October) using an adapted ventral-massage technique (Molinia et al. 2010 Herp. Cons. Biol. 5, 311-319 retrieved from www.herpconbio.org). Sperm metrics (volume, concentration, progressive and total motility, and membrane integrity) were assessed subjectively under light or fluorescence microscopy. Results were compared using ANOVA. Sperm volume (9.43±5.18μL) and concentration (7.79×108±5.32×108 sperm/mL) did not correlate with snout-vent length in adult males (r2=0.025 and r2=0.15, respectively). Due to small volumes, sperm s les (motility & %) from 4 to 6 males were pooled before allocation across treatments. For all cryopreservation experiments, sperm s les (5-10μL) were loaded into 0.2-mL French straws and frozen using a controlled-rate freezer (Cryobath −6°C per minute), then plunged into LN. Sperm were thawed in a water bath at 35°C for 10s. In year 1, pooled s les (n=3) were maintained at room temperature (21±1.5°C) either raw, or diluted in PBS, Tris-citrate glucose, TLHepes, or Ham’s F-10 and assessed at 0, 1, 3, 16, 40h. Tris-citrate-glucose-diluted sperm had significantly lower total motility from 3h (36.7±11.5% P& .05), decreasing to 1% motility by 16h. Up to 70% motility could be maintained for 16h in all other treatment groups. In year 2, pooled s les (n=3) were cooled to 4°C over a period of 2h, then gradually diluted 1:1 with buffer to a final concentration of either 0.6, 1.35, or 2.7M cryoprotectant (CPA dimethyl sulfoxide, dimethyl acetamide, glycerol) in PBS or no CPA. Sperm diluted in 1.35 and 2.7M dimethyl sulfoxide in PBS had significantly (P& .05) higher kinetic rating and proportion of live sperm than control or dimethyl acetamide treatments 1.35 and 2.7M glycerol were intermediate. In year 3, dilution and cryopreservation using 1.35M CPA in complex diluents, Tris-yolk buffer (20.1±2.6% live) and Beltsville poultry semen extender (29.7±2.0% live), did not significantly improve sperm survival compared to PBS (26.4±2.7% live) however, post-thaw progressive motility (5±1.1%) was significantly (P & 0.05) higher with 1.35M dimethyl sulfoxide Tris-yolk buffer than all other treatment groups. In conclusion, dimethyl sulfoxide yields promise for sperm cryopreservation in a skink, but further studies are required.
Publisher: Elsevier BV
Date: 04-2000
Publisher: Oxford University Press (OUP)
Date: 03-2018
Publisher: University of Chicago Press
Date: 12-2013
DOI: 10.1086/673535
Abstract: Alternative reproductive tactics (ARTs) are predicted to be the result of disruptive correlational selection on suites of morphological, physiological, and behavioral traits. ARTs are most obvious when they occur in discrete morphs with concomitant behavioral tactics. However, ARTs driven by behavior in species lacking obvious phenotypic differences are rarely documented and poorly understood. We quantified selection acting on phenotypic traits predicted to characterize ARTs by observing marked lizards in six seminatural populations. We quantified reproductive fitness for each male using six microsatellite DNA loci from 226 offspring born to 56 females. Candidate models containing directional and correlational selection gradients were equally supported. As predicted, large males with large home ranges and large males that were observed frequently had the highest reproductive success. We also found evidence that large males that moved little but that were observed frequently and large males that moved frequently but that were observed little were predicted to have high fitness. Model predictions support our verbal hypothesis regarding the phenotypes characterizing ARTs and suggest that large males may be adopting subtly different tactics to acquire paternity. Our results suggest that disruptive correlational selection between behavioral traits may drive the evolution of ARTs in "cryptic" systems that lack overt polymorphisms.
Publisher: Brill
Date: 1996
Abstract: Activity patterns for two populations of the Concho water snake (Nerodia harteri paucimaculata) were studied in a large lake system in central Texas, USA, and compared to a river population. Trap data suggested different activity patterns for the two geographically proximate lake populations. Testing of the trap data using the program CAPTURE revealed differences in catchability rather than activity cycles. Based on these results, the apparent activity patterns for one of the lake sites was considered erroneous and the differences in catchability were ascribed to habitat differences. It is suggested that future studies should incorporate a test of equal catchability when making interpopulational comparisons.
Publisher: Society for the Study of Amphibians and Reptiles
Date: 19-12-2022
DOI: 10.1670/20-113
Publisher: American Psychological Association (APA)
Date: 05-2021
DOI: 10.1037/COM0000260
Publisher: Wiley
Date: 25-06-2007
Publisher: Springer Science and Business Media LLC
Date: 30-06-2015
Publisher: American Society of Ichthyologists and Herpetologists (ASIH)
Date: 04-06-2008
DOI: 10.1643/CE-06-271
Publisher: Springer Science and Business Media LLC
Date: 25-09-2021
DOI: 10.1186/S12983-021-00431-Y
Abstract: Quantity discrimination, the ability to discriminate a magnitude of difference or discrete numerical information, plays a key role in animal behavior. While quantitative ability has been well documented in fishes, birds, mammals, and even in previously unstudied invertebrates and hibians, it is still poorly understood in reptiles and has never been tested in an aquatic turtle despite the fact that evidence is accumulating that reptiles possess cognitive skills and learning ability. To help address this deficiency in reptiles, we investigated the quantitative ability of an Asian freshwater turtle, Mauremys sinensis , using red cubes on a white background in a trained quantity discrimination task. While spontaneous quantity discrimination methods are thought to be more ecologically relevant, training animals on a quantity discrimination task allows more comparability across taxa. We assessed the turtles’ quantitative performance in a series of tests with increasing quantity ratios and numerosities. Surprisingly, the turtles were able to discriminate quantities of up to 9 versus 10 (ratio = 0.9), which shows a good quantitative ability that is comparable to some endotherms. Our results showed that the turtles’ quantitative performance followed Weber’s law, in which success rate decreased with increasing quantity ratio across a wide range of numerosities. Furthermore, the gradual improvement of their success rate across different experiments and phases suggested that the turtles possess learning ability. Reptile quantitative ability has long been ignored and therefore is likely under-estimated. More comparative research on numerical cognition across a ersity of species will greatly contribute to a clearer understanding of quantitative ability in animals and whether it has evolved convergently in erse taxa.
Publisher: Elsevier BV
Date: 02-2014
DOI: 10.1016/J.YMPEV.2013.11.012
Abstract: Jacky dragons (Amphibolurus muricatus) are ubiquitous in south-eastern Australia and were one of the first Australian reptiles to be formally described. Because they are so common, Jacky dragons are widely used as a model system for research in evolutionary biology and ecology. In addition, their distribution along the Great Dividing Range of eastern Australia provides an opportunity to examine the influence of past biogeographical processes, particularly the expansion and contraction of forest habitats, on the ersification of this iconic agamid lizard. We generated sequence data for two mitochondrial and three nuclear DNA loci (4251base pairs) for 62 Jacky dragons s led from throughout their distribution. Phylogenetic analyses based on maximum likelihood and Bayesian species-tree methods revealed five geographically structured clades separated by up to 6% mitochondrial and 0.7% nuclear sequence ergence. We also quantified body proportion variation within and between these genetic clades for more than 500 specimens and found no evidence of any significant differentiation in body proportions across their range. Based on body proportion homogeneity and lack of resolution in the nuclear loci, we do not support taxonomic recognition of any of the mitochondrial clades. Instead, A. muricatus is best thought of as a single species with phylogeographic structure. The genetic patterns observed in the Jacky dragon are consistent with fragmented populations reduced to multiple refugia during cold, arid phases when forested habitats were greatly restricted. Consequently, the inferred biogeographic barriers for this taxon appear to be in line with lowland breaks in the mountain ranges. Our results are congruent with studies of other reptiles, frogs, mammals, birds and invertebrates, and together highlight the overarching effects of widespread climatic and habitat fluctuations along the Great Dividing Range since the Pliocene.
Publisher: JSTOR
Date: 09-12-1997
DOI: 10.2307/1447298
Publisher: The Royal Society
Date: 03-01-2006
Abstract: Ultraviolet (UV) signals are used in female mate choice in numerous taxa however, the role of UV signals in male contests remains relatively unexplored. We experimentally reduced throat UV of free-ranging lizards ( Platysaurus broadleyi ) to test whether UV acts as a signal of fighting ability during male contests. We found that UV-reduced males were more likely to be challenged than control males. However, contest outcome was not influenced by UV-reduction, and this was despite other obvious asymmetries between opponents, such as body size and residency. Throat UV was confirmed as a signal of fighting ability because contests were more likely to escalate when one contestant had reduced UV. Therefore, throat UV, not body size or residency, was used during the initial stage of opponent assessment, but this did not influence contest outcome. The results suggest that UV overrides other traits that could function as signals during rival assessment.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 08-03-2019
Abstract: Understanding the rich social lives of animals benefits international conservation efforts
Publisher: CRC Press
Date: 06-02-2019
Publisher: Springer Science and Business Media LLC
Date: 13-01-2018
Publisher: CRC Press
Date: 06-02-2019
Publisher: University of Chicago Press
Date: 12-2007
DOI: 10.1086/522835
Abstract: Whether general patterns of signal evolution can be explained by selection for signal efficacy (detectability) has yet to be established. To establish the importance of signal efficacy requires evidence that both signals and their detectability to receivers have evolved in response to habitat shifts in a predictable fashion. Here, we test whether habitat structure has predictable effects on the evolution of male and female display coloration in 21 lineages of African dwarf chameleon (Bradypodion), based on a phylogenetic comparative analysis. We used quantitative measures of display coloration and estimated signal detectability as the contrast of those colors among body regions or against the background vegetation as perceived by the chameleon visual system. Both male and female display colors varied predictably with different aspects of habitat structure. In several (but not all) instances, habitat-associated shifts in display coloration resulted in habitat-associated variation in detectability. While males exhibit a remarkable variety of colors and patterns, female display coloration is highly conserved, consisting in all populations of contrasting dark and light elements. This color pattern may maximize detectability across all habitat types, potentially explaining female conservatism. Overall, our results support the view that selection for signal efficacy plays an important role in the evolution of animal signals.
Publisher: Informa UK Limited
Date: 1997
Publisher: Springer Science and Business Media LLC
Date: 02-2019
DOI: 10.1007/S10071-019-01245-6
Abstract: Response inhibition (inhibiting prepotent responses) is needed for reaching a more favourable goal in situations where reacting automatically would be detrimental. Inhibiting prepotent responses to resist the temptation of a stimulus in certain situations, such as a novel food item, can directly affect an animal's survival. In humans and dogs, response inhibition varies between contexts and between in iduals. We used two contextually different experiments to investigate response inhibition in the eastern water skink (Eul rus quoyii): reversal of a visual two-choice discrimination and a cylinder detour task. During the two-choice task, half of our lizards were able to reach an initial learning criterion, but, thereafter, did not show consistent performance. Only two in iduals reached a more stringent criterion, but subsequently failed during reversals. Furthermore, half of our animals were not able to inhibit a pre-existing side preference which affected their ability to learn during the two-choice task. Skinks were, however, able to achieve a detour around a cylinder performing at levels comparable to brown lemurs, marmosets, and some parrot species. A comparison between the tasks showed that reaching the initial criterion was associated with low success during the detour task, indicating that response inhibition could be context-specific in the water skink. To the best of our knowledge, this is the first study to examine inhibitory control and motor self-regulation in a lizard species.
Publisher: Elsevier BV
Date: 08-2019
Publisher: Wiley
Date: 12-10-2006
Publisher: Wiley
Date: 13-01-2006
Publisher: Springer Science and Business Media LLC
Date: 11-10-2014
Publisher: Elsevier BV
Date: 07-2019
DOI: 10.1016/J.BEPROC.2019.04.002
Abstract: We have a poor understanding of differences in learning performance between male and female non-avian reptiles compared to other vertebrates. Learning studies in non-avian reptiles have greatly increased in the last 10 years providing an opportunity to test for sex-based learning using a meta-analysis. Although, we initially considered all reptiles, only lizard studies (N = 11) provided sufficient data to calculate effect sizes. We found weak evidence for sex-dependent learning and moderate heterogeneity in effect sizes across studies. Although, our hypothesized moderator variables (stimulus or task type, species, genus and family) explained little variation. Indeed, our results show that only one species (Egernia striolata) exhibited a sex-dependent learning difference, with males learning faster than females. Together, our meta-analysis indicated a general lack of effective reporting on attributes of study methodology (i.e., animal sex, s le sizes). We propose that future research improve reporting by openly sharing their data for the use in similar analyses. The limited s le currently constrains our ability to effectively disentangle whether sex differences vary across different tasks and stimuli. We urge authors to incorporate both sexes in experimental designs and test them on ecologically relevant cognitive assays to improve our understanding of the degree of sex differences in non-avian reptile learning.
Publisher: The Royal Society
Date: 05-2017
DOI: 10.1098/RSOS.161082
Abstract: Early social environment can play a significant role in shaping behavioural development. For instance, in many social mammals and birds, isolation rearing results in in iduals that are less exploratory, shyer, less social and more aggressive than in iduals raised in groups. Moreover, dynamic aspects of social environments, such as the nature of relationships between in iduals, can also impact the trajectory of development. We tested if being raised alone or socially affects behavioural development in the family-living tree skink, Egernia striolata . Juveniles were raised in two treatments: alone or in a pair. We assayed exploration, boldness, sociability and aggression repeatedly throughout each juvenile's first year of life, and also assessed social interactions between pairs to determine if juveniles formed dominant–subordinate relationships. We found that male and/or the larger skinks within social pairs were dominant. Developing within this social environment reduced skink growth, and subordinate skinks were more prone to tail loss. Thus, living with a conspecific was costly for E. striolata . The predicted negative effects of isolation failed to materialize. Nevertheless, there were significant differences in behavioural traits depending on the social environment (isolated, dominant or subordinate member of a pair). Isolated skinks were more social than subordinate skinks. Subordinate skinks also became more aggressive over time, whereas isolated and dominant skinks showed invariable aggression. Dominant skinks became bolder over time, whereas isolated and subordinate skinks were relatively stable in their boldness. In summary, our study is evidence that isolation rearing does not consistently affect behaviour across all social taxa. Our study also demonstrates that the social environment plays an important role in behavioural development of a family-living lizard.
Publisher: The Royal Society
Date: 09-03-2011
Abstract: Progress in developing animal communication theory is frequently constrained by a poor understanding of sensory systems. For ex le, while lizards have been the focus of numerous studies in visual signalling, we only have data on the spectral sensitivities of a few species clustered in two major clades (Iguania and Gekkota). Using electroretinography and microspectrophotometry, we studied the visual system of the cordylid lizard Platysaurus broadleyi because it represents an unstudied clade (Scinciformata) with respect to visual systems and because UV signals feature prominently in its social behaviour. The retina possessed four classes of single and one class of double cones. Sensitivity in the ultraviolet region (UV) was approximately three times higher than previously reported for other lizards. We found more colourless oil droplets (associated with UV-sensitive (UVS) and short wavelength-sensitive (SWS) photoreceptors), suggesting that the increased sensitivity was owing to the presence of more UVS photoreceptors. Using the Vorobyev–Osorio colour discrimination model, we demonstrated that an increase in the number of UVS photoreceptors significantly enhances a lizard's ability to discriminate conspecific male throat colours. Visual systems in diurnal lizards appear to be broadly conserved, but data from additional clades are needed to confirm this.
Publisher: Elsevier BV
Date: 05-2021
Publisher: Museum of Comparative Zoology, Harvard University
Date: 07-09-2012
DOI: 10.3099/532.1
Publisher: Cambridge University Press
Date: 24-03-2017
Publisher: Elsevier BV
Date: 03-2005
Publisher: Elsevier BV
Date: 10-2018
Publisher: Oxford University Press (OUP)
Date: 07-03-2018
Publisher: Elsevier BV
Date: 2013
Publisher: Elsevier BV
Date: 06-2013
Publisher: The Royal Society
Date: 25-02-2009
Abstract: Understanding what constrains signalling and maintains signal honesty is a central theme in animal communication. Clear cases of dishonest signalling, and the conditions under which they are used, represent an important avenue for improved understanding of animal communication systems. Female mimicry, when certain males take on the appearance of females, is most commonly a male alternative reproductive tactic that is condition-dependent. A number of adaptive explanations for female mimicry have been proposed including avoiding the costs of aggression, gaining an advantage in combat, sneaking copulations with females on the territories of other males, gaining physiological benefits and minimizing the risk of predation. Previous studies of female mimicry have focused on a single mode of communication, although most animals communicate using multiple signals. Male Augrabies flat lizards adopt alternative reproductive tactics in which some males (she-males) mimic the visual appearance of females. We experimentally tested in a wild population whether she-males are able to mimic females using both visual and chemical signals. We tested chemical recognition in the field by removing scent and relabelling females and she-males with either male or female scent. At a distance, typical males (he-males) could not distinguish she-males from females using visual signals, but during close encounters, he-males correctly determined the gender of she-males using chemical signals. She-males are therefore able to deceive he-males using visual but not chemical signals. To effectively deceive he-males, she-males avoid close contact with he-males during which chemical cues would reveal their deceit. This strategy is probably adaptive, because he-males are aggressive and territorial by mimicking females, she-males are able to move about freely and gain access to females on the territories of resident males.
Publisher: Oxford University Press (OUP)
Date: 10-07-2018
Publisher: Springer Science and Business Media LLC
Date: 06-2023
DOI: 10.1007/S00265-023-03343-5
Abstract: When different modes of communication are used in combination and for ex le convey visual and acoustic information, they form a multimodal signal. Frogs are best known for using acoustic communication, but many species also use visual or colour signals, some of which are dynamic, and may be combined with acoustic signals. In this context, the question of whether these two modes of communication reinforce the same message or offer different information is poorly understood. Male whirring tree frogs, Litoria revelata , use a multimodal signal during courtship, which combines a vocalisation and dynamic sexual dichromatism, with nuptial display colours shifting from brown or grey to bright yellow. Here, we examined the properties of the advertisement call and nuptial colour of vocalising male whirring tree frogs and tested whether the two signals were likely to reinforce each other or convey independent information. We found only weak associations between elements of male colouration and vocalisations, suggesting that advertisement calls and nuptial colour do not reinforce each other and that the signals may instead convey different information. Dynamic nuptial colour and vocalisation in combination is a relatively common multimodal signal in frogs but is unstudied. We looked for relationships between properties of colour and vocalisation in an Australian tree frog to explore whether the two sensory modes formed backup signals or multiple messages. We did not find predictive relationships between nuptial colour and vocalisation, supporting the multiple messages hypothesis and suggesting that nuptial colour is not necessarily directed at females for the purposes of mate attraction, potentially differing from the assumed function of the vocalisation. Our study is also the first to formally characterise aspects of dynamic sexual dichromatism in the whirring tree frog ( Litoria revelata ) and the first to describe the advertisement call of this species in its southern distribution. Whilst we do not specifically address the function of dynamic sexual dichromatism in this species, our findings do not contradict the existing literature in respect to it being a male-male directed signal.
Publisher: CSIRO Publishing
Date: 03-02-2022
DOI: 10.1071/ZO21023
Abstract: Sex is a pervasive factor that underpins functional phenotypic variation across a range of traits. Although sex can usually be distinguished morphologically, in some species this is not possible. The development of genetic markers for sex identification is, thus, key if we are to incorporate sex into an understanding of ecological or evolutionary process. Here we develop genetic markers for the identification of sex within an iconic Australian lizard group, the Egernia group, which is notable for its complex social behaviour. We used restriction-site associated DNA sequencing to characterise sex-specific genetic sequences for a key member of the group, Liopholis whitii, and designed primers for four of these putative sex-specific sequences. These primers lified across some, but not all, species of the group. Our results provided several important insights. They suggest conservatism of a XX/XY sex determination system within the group as well as sex-specific genomic regions that appear independent of the conserved genomic regions identified in other skink species. More broadly, the development of sex markers for the Egernia group opens up a range of potential research questions related to the role that sex plays in the mediation of social behaviour and, through this, the emergence and stability of social life.
Publisher: Springer Science and Business Media LLC
Date: 05-09-2020
Publisher: Wiley
Date: 04-08-2022
DOI: 10.1111/MEC.16633
Abstract: Gene expression levels are key molecular phenotypes at the interplay between genotype and environment. Mounting evidence suggests that short‐term changes in environmental conditions, such as those encountered in captivity, can substantially affect gene expression levels. Yet, the exact magnitude of this effect, how general it is, and whether it results in parallel changes across populations are not well understood. Here, we take advantage of the well‐studied cane toad, Rhinella marina , to examine the effect of short‐term captivity on brain gene expression levels, and determine whether effects of captivity differ between long‐colonized and vanguard populations of the cane toad's Australian invasion range. We compared the transcriptomes of wild‐caught toads immediately assayed with those from toads captured from the same populations but maintained in captivity for seven months. We found large differences in gene expression levels between captive and wild‐caught toads from the same population, with an over‐representation of processes related to behaviour and the response to stress. Captivity had a much larger effect on both gene expression levels and gene expression variability in toads from vanguard populations compared to toads from long‐colonized areas, potentially indicating an increased plasticity in toads at the leading edge of the invasion. Overall, our findings indicate that short‐term captivity can induce large and population‐specific transcriptomic changes, which has significant implications for studies comparing phenotypic traits of wild‐caught organisms from different populations that have been held in captivity.
Publisher: University of Chicago Press
Date: 06-2015
DOI: 10.1086/681021
Abstract: The world in color presents a dazzling dimension of phenotypic variation. Biological interest in this variation has burgeoned, due to both increased means for quantifying spectral information and heightened appreciation for how animals view the world differently than humans. Effective study of color traits is challenged by how to best quantify visual perception in nonhuman species. This requires consideration of at least visual physiology but ultimately also the neural processes underlying perception. Our knowledge of color perception is founded largely on the principles gained from human psychophysics that have proven generalizable based on comparative studies in select animal models. Appreciation of these principles, their empirical foundation, and the reasonable limits to their applicability is crucial to reaching informed conclusions in color research. In this article, we seek a common intellectual basis for the study of color in nature. We first discuss the key perceptual principles, namely, retinal photoreception, sensory channels, opponent processing, color constancy, and receptor noise. We then draw on this basis to inform an analytical framework driven by the research question in relation to identifiable viewers and visual tasks of interest. Consideration of the limits to perceptual inference guides two primary decisions: first, whether a sensory-based approach is necessary and justified and, second, whether the visual task refers to perceptual distance or discriminability. We outline informed approaches in each situation and discuss key challenges for future progress, focusing particularly on how animals perceive color. Given that animal behavior serves as both the basic unit of psychophysics and the ultimate driver of color ecology/evolution, behavioral data are critical to reconciling knowledge across the schools of color research.
Publisher: JSTOR
Date: 02-08-1999
DOI: 10.2307/1447602
Publisher: Public Library of Science (PLoS)
Date: 12-02-2013
Publisher: The Company of Biologists
Date: 10-2021
DOI: 10.1242/JEB.242939
Abstract: Animals that habitually cross the boundary between water and land face specific challenges with respect to locomotion, respiration, insulation, fouling and waterproofing. Many semi-aquatic invertebrates and plants have developed complex surface microstructures with water-repellent properties to overcome these problems, but equivalent adaptations of the skin have not been reported for vertebrates that encounter similar environmental challenges. Here, we document the first evidence of evolutionary convergence of hydrophobic structured skin in a group of semi-aquatic tetrapods. We show that the skin surface of semi-aquatic species of Anolis lizards is characterized by a more elaborate microstructural architecture (i.e. longer spines and spinules) and a lower wettability relative to closely related terrestrial species. In addition, phylogenetic comparative models reveal repeated independent evolution of enhanced skin hydrophobicity associated with the transition to a semi-aquatic lifestyle, providing evidence of adaptation. Our findings invite a new and exciting line of inquiry into the ecological significance, evolutionary origin and developmental basis of hydrophobic skin surfaces in semi-aquatic lizards, which is essential for understanding why and how the observed skin adaptations evolved in some and not other semi-aquatic tetrapod lineages.
Publisher: Springer Berlin Heidelberg
Date: 19-09-2012
Publisher: Elsevier BV
Date: 03-2020
DOI: 10.1016/J.BEPROC.2020.104043
Abstract: Waiting for the right moment to strike, avoiding the ingestion of harmful foods, or ignoring stimuli associated with ephemeral or depleted resources requires the inhibition of prepotent responses. Good response inhibition facilities flexibility in behaviour which is associated with survival in unpredictable environments. To investigate differences in behavioural flexibility in lizards, we tested reversal learning in the sleepy lizard (Tiliqua rugosa asper) and compared its performance to the relatively closely related eastern blue-tongue skink (Tiliqua scincoides scincoides). We presented both species with a choice between either a light and dark blue stimulus or a triangle and X shape. Both species were able to learn to discriminate between these stimuli and showed similar learning ability during the acquisition of the discrimination. Sleepy lizards, however, demonstrated a higher probability of making a correct choice at the start of the reversal, hinting towards enhanced stimulus response inhibition. Sleepy lizards and blue-tongue skinks inhabit different environments and show differences in ecology and sociobiology, all of which could possibly lead to adaptive specialisation in cognitive ability. Although further research is required, we propose that selection might have led to a change in stimulus response inhibition in the arid-adapted sleepy lizard, because better response inhibition may help them avoid the costs of repeated choices towards stimuli which no longer predict a beneficial outcome.
Publisher: Springer Science and Business Media LLC
Date: 11-2003
Publisher: Oxford University Press (OUP)
Date: 15-03-2014
Publisher: Springer Science and Business Media LLC
Date: 02-10-2014
Publisher: The Royal Society
Date: 21-04-2021
Abstract: A key goal of conservation is to protect bio ersity by supporting the long-term persistence of viable, natural populations of wild species. Conservation practice has long been guided by genetic, ecological and demographic indicators of risk. Emerging evidence of animal culture across erse taxa and its role as a driver of evolutionary ersification, population structure and demographic processes may be essential for augmenting these conventional conservation approaches and decision-making. Animal culture was the focus of a ground-breaking resolution under the Convention on the Conservation of Migratory Species of Wild Animals (CMS), an international treaty operating under the UN Environment Programme. Here, we synthesize existing evidence to demonstrate how social learning and animal culture interact with processes important to conservation management. Specifically, we explore how social learning might influence population viability and be an important resource in response to anthropogenic change, and provide ex les of how it can result in phenotypically distinct units with different, socially learnt behavioural strategies. While identifying culture and social learning can be challenging, indirect identification and parsimonious inferences may be informative. Finally, we identify relevant methodologies and provide a framework for viewing behavioural data through a cultural lens which might provide new insights for conservation management.
Publisher: Public Library of Science (PLoS)
Date: 23-07-2012
Publisher: The Royal Society
Date: 10-2018
Abstract: Species that are able to solve novel problems through social learning from either a conspecific or a heterospecific may gain a significant advantage in new environments. We tested the ability of a highly successful invasive species, the Italian wall lizard Podarcis sicula , to solve a novel foraging task when social information was available from both a conspecific and an unfamiliar heterospecific ( Podarcis bocagei ). We found that Italian wall lizards that had access to social information made fewer errors, regardless of whether the demonstrator was a conspecific or a heterospecific, compared to Italian wall lizards that in idually learnt the same task. We suggest that social learning could be a previously underappreciated, advantageous mechanism facilitating invasions.
Publisher: Elsevier BV
Date: 04-2017
DOI: 10.1016/J.JTHERBIO.2017.02.005
Abstract: Pregnancy is a challenging period for egg laying squamates. Carrying eggs can encumber females and decrease their locomotor performance, potentially increasing their risk of predation. Pregnant females can potentially reduce this handicap by selecting higher temperatures to increase their sprint speed and ability to escape from predators, or to speed up embryonic development and reduce the period during which they are burdened with eggs ('selfish mother' hypothesis). Alternatively, females might select more stable body temperatures during pregnancy to enhance offspring fitness ('maternal manipulation hypothesis'), even if the maintenance of such temperatures compromises a female's locomotor performance. We investigated whether pregnancy affects the preferred body temperatures and locomotor performance of female velvet geckos Amalosia lesueurii. We measured running speed of females during late pregnancy, and one week after they laid eggs at four temperatures (20°, 25°, 30° and 35°C). Preferred body temperatures of females were measured in a cost-free thermal gradient during late pregnancy and one week after egg-laying. Females selected higher and more stable set-point temperatures when they were pregnant (mean =29.0°C, T
Publisher: The Royal Society
Date: 10-2021
Abstract: Anticipatory behaviour is the expectation of a near-future event based on information processed in the past and influences an animal's tactical decisions, particularly when there are significant fitness consequences. The grass lizard ( Takydromus viridipunctatus ) perches on blades of grass at night which likely reduces the probability of predation by terrestrial predators such as snakes, rodents and shrews. During twilight (starting 30 min before sunrise), they move from above the grass to within grass clumps and this is thought to afford the lizard protection while reducing detection by avian predators. Here, we examined how lizards shift their behaviour as a function of visual detectability to their primary predator, the cattle egret ( Bubulcus ibis ). We show that the lizards shift from their perch site during twilight at the earliest time at which egrets depart communal roosts. At the same time, visual modelling shows a dramatic increase in the detectability of the lizards to the visual system of egrets. Therefore, anticipatory behaviour in response to environmental cues acts to reduce predation risk as lizards become more conspicuous and predators become more active. Grass lizard anticipatory behaviour appears to be finely tuned by natural selection to adjust to temporal changes in predation risk.
Publisher: Informa UK Limited
Date: 04-2007
Publisher: The Royal Society
Date: 17-02-2021
Abstract: The evolution of sociality and traits that correlate with, or predict, sociality, have been the focus of considerable recent study. In order to reduce the social conflict that ultimately comes with group living, and foster social tolerance, in iduals need reliable information about group members and potential rivals. Chemical signals are one such source of information and are widely used in many animal taxa, including lizards. Here, we take a phylogenetic comparative approach to test the hypothesis that social grouping correlates with investment in chemical signalling. We used the presence of epidermal glands as a proxy of chemical investment and considered social grouping as the occurrence of social groups containing both adults and juveniles. Based on a dataset of 911 lizard species, our models strongly supported correlated evolution between social grouping and chemical signalling glands. The rate of transition towards social grouping from a background of ‘epidermal glands present’ was an order of a magnitude higher than from a background of ‘no epidermal glands’. Our results highlight the potential importance of chemical signalling during the evolution of sociality and the need for more focused studies on the role of chemical communication in facilitating information transfer about in idual and group identity, and ameliorating social conflict.
Publisher: Wiley
Date: 30-12-2022
DOI: 10.1111/JZO.12951
Abstract: Hatching/birthing asynchrony, when siblings emerge at least 12 h apart, is thought to be a significant driver of phenotypic variation and group cohesion that is commonly reported in invertebrates and birds, but rarely in squamates. We examined birthing asynchrony in African cordylid lizards (Cordylidae), a clade characterized by a wide range of sociality (a hypothesized evolutionary driver of this unique phenomenon). We monitored parturition from wild‐caught mothers from four species, which vary in their conspecific grouping behaviour. In two species, most litters were born asynchronously, over a maximum of 3–4 days respectively. The other two cordylids also exhibited asynchronous birth in all litters with more than one offspring, although this was not applicable for most litters because there was a prevalence of singleton litters. Our study uncovered birthing asynchrony in a novel taxonomic group, which suggests it evolved convergently in at least two social lizard clades from different continents. Furthermore, the function of birthing asynchrony and limiting litter size to a single offspring may be similar in social animals. We discuss the potential significance of this rare phenomenon in this disparate taxon, and compare it with other more well‐studied taxa, in order to guide future research directions.
Publisher: Elsevier BV
Date: 09-2021
Publisher: Springer Science and Business Media LLC
Date: 07-09-2020
DOI: 10.1007/S00265-020-02897-Y
Abstract: Inhibitory control, the inhibition of prepotent actions, is essential for higher-order cognitive processes such as planning, reasoning, and self-regulation. In iduals and species differ in inhibitory control. Identifying what influences inhibitory control ability within and between species is key to understanding how it evolved. We compared performance in the cylinder task across five lizard species: tree skinks ( Egernia striolata ), gidgee skinks ( Egernia stokesii ), eastern blue-tongue skinks ( Tiliqua s. scincoides ), sleepy lizards ( Tiliqua r. asper ), and eastern water skinks ( Eul rus quoyii ). In our task, animals had to inhibit the prepotent motor response of directly approaching a reward placed within a semi-transparent mesh cylinder and instead reach in through the side openings. Additionally, in three lizard species, we compared performance in the cylinder task to reversal learning to determine the task specificity of inhibitory ability. Within species, neither sex, origin, body condition, neophobia, nor pre-experience with other cognitive tests affected in idual performance. Species differed in motor response inhibition: Blue-tongue skinks made fewer contacts with the semi-transparent cylinder wall than all other species. Blue-tongue skinks also had lower body condition than the other species which suggest motivation as the underlying cause for species differences in task performance. Moreover, we found no correlation between inhibitory ability across different experiments. This is the first study comparing cylinder task performance among lizard species. Given that inhibitory control is probably widespread in lizards, motor response inhibition as exercised in the cylinder task appears to have a long evolutionary history and is likely fundamental to survival and fitness. The study of lizard cognition is receiving increasing attention. Lizards are a erse group with a wide range of ecological attributes and represent a model system through which we can test a wide range of hypotheses relating to cognitive evolution. Furthermore, considering their evolutionary history, studying non-avian reptile cognition can help understand the evolution of different cognitive abilities including inhibitory control. Here, we provide a comparison of inhibitory control ability in five lizard species. Consequently, we are able to, firstly, validate a method (the cylinder task) initially developed for the use in mammals and birds, for use in lizards, and secondly, collect valuable data on inhibitory control in a poorly studied group with respect to cognitive ability. Our study suggests non-cognitive factors as a major influence on cylinder task performance, which is in agreement with previous studies of other vertebrates.
Publisher: Oxford University Press (OUP)
Date: 17-12-2019
DOI: 10.1093/BIOLINNEAN/BLZ176
Abstract: When faced with a predator, some animals engage in a deimatic display to startle the predator momentarily, resulting in a pause or retreat, thereby increasing their chance of escape. Frillneck lizards (Chlamydosaurus kingii) are characterised by a large, pronounced frill that extends from the base of the head to beyond the neck and, when displayed, can be up to six times the width of the head. We used behavioural assays with a model avian predator to demonstrate that their display conforms to deimatic display theory. First, juveniles and adults deployed the frill in encounters with a model predator. Second, the display revealed three colour patches (white and red–orange patches on the frill yellow mouth palate) that facilitate a transition from a cryptic to a conspicuous state as perceived by a raptor visual system. Third, the display was performed with movements that lified its effect. The frill area was larger in males than in females, which suggests that the frill might also be co-opted for male–male contests. If future research confirms a role of the frill in male agonistic interactions, frillneck lizards will be a rare case in which a structure has a dual function in a deimatic display and a sexually selected signal.
Publisher: Oxford University Press (OUP)
Date: 13-03-2014
DOI: 10.1111/BIJ.12252
Publisher: Wiley
Date: 04-08-2005
Publisher: American Society of Ichthyologists and Herpetologists (ASIH)
Date: 17-12-2010
DOI: 10.1643/CE-09-134
Publisher: Elsevier BV
Date: 08-2018
DOI: 10.1016/J.BEPROC.2018.05.001
Abstract: Behavioural responses to repeated trials in captivity can be driven by many factors including rearing environment, population of origin, habituation to captivity/trial conditions and an in idual's behavioural type (e.g., bold versus shy). We tested the effect of rearing environment (captive raised common-garden versus wild-caught) and population origin (range-edge versus range-front) on the responses of invasive cane toads (Rhinella marina) to repeated exploration and risk-taking assays in captivity. We found that behavioural responses to identical assays performed on two occasions were complex and showed few consistent patterns based on rearing environment or population of origin. However, behavioural traits were repeatable across Trial Blocks when all s le populations were grouped together, indicating general consistency in in idual toad behaviour across repeated behavioural assays. Our findings exemplify the complexity and unpredictability of behavioural responses and their effects on the repeatability and interpretation of behavioural traits across repeated behavioural assays in captivity. To meaningfully interpret the results from repeated behavioural assays, we need to consider how multiple factors may affect behavioural responses to these tests and importantly, how these responses may affect the repeatability of behavioural traits across time.
Publisher: Springer Science and Business Media LLC
Date: 22-01-2013
Publisher: Wiley
Date: 25-04-2023
DOI: 10.1111/ETH.13379
Abstract: Wild animals are often concurrently infected by multiple parasites, which are assumed to negatively affect their host by exploiting the host's resources. The cumulative effect of parasite infections is often not studied. Despite this assumption, many hosts do not suffer significant costs from parasitism in the wild. Hosts can adapt to parasitic infections by mounting physiological and behavioural defences. A commonly used behavioural defence by ectotherms is to frequently visit warm environments to increase body temperature (i.e., behavioural fever) and thereby mount an immune response to parasites. Using the Australian common garden skink ( L ropholis guichenoti ), we investigated the cumulative effect of endo‐ and ectoparasites on host performance. First, we investigated whether endo‐ and ectoparasites were associated with whole‐organism performance in the lizards. Second, we explored whether host in iduals responded to their parasite infection through thermoregulatory behaviour. We found no significant relationship between parasitism and body condition. However, the infection with ectoparasitic mites was significantly related to reduced sprint speed, while the nematode infection had no significant relationship with any of our three performance measures (sprint speed, endurance and foraging efficiency). We showed no evidence of behavioural fever and infected lizards did not differ in their body temperature from uninfected lizards. Our findings suggest that short‐lived lizards may simply endure parasitic infections. The study provides an important ex le of how multiple infections with endo‐ and ectoparasites affect their host. It adds to the growing evidence for a negligible effect of parasites on host whole‐organism performance.
Publisher: Wiley
Date: 06-03-2017
DOI: 10.1111/MEC.14042
Abstract: Some of the best evidence for rapid evolutionary change comes from studies of archipelagos and oceanic islands. City parks are analogous systems as they create geographically isolated green spaces that differ in size, structure and complexity. Very little, however, is known about whether city parks within a single urban centre drive selection and result in the ersification of native species. Here, we provide evidence for the rapid genetic and morphological differentiation of a native lizard (Intellagama lesueurii) at four geographically close yet unconnected parks within one city. Year of establishment of each city park varied from 1855 (oldest) to 2001 (youngest) equating to a generation time range of 32 to three generations. Genetic ergence among city park populations was large despite the small pairwise geographic distances (<5 km) and found to be two to three times higher for microsatellites and three to 33 times higher for mtDNA relative to nonurban populations. Patterns of morphological differentiation were also found to be most extensive among the four city park populations. In contrast to nonurban populations, city park populations showed significant differentiation in relative body size, relative head and limb morphology and relative forelimb and hindlimb length. Crucially, we show that these patterns of differentiation are unlikely to have been caused by founder events and/or drift alone. Our results suggest that city park 'archipelagos' could represent theatres for rapid evolution that may, in time, favour adaptive ersification.
Publisher: Springer Science and Business Media LLC
Date: 21-01-2017
Publisher: Springer Science and Business Media LLC
Date: 26-12-2017
DOI: 10.1007/S10071-016-1068-0
Abstract: Early developmental environment can have profound effects on in idual physiology, behaviour, and learning. In birds and mammals, social isolation during development is known to negatively affect learning ability yet in other taxa, like reptiles, the effect of social isolation during development on learning ability is unknown. We investigated how social environment affects learning ability in the family-living tree skink (Egernia striolata). We hypothesized that early social environment shapes cognitive development in skinks and predicted that skinks raised in social isolation would have reduced learning ability compared to skinks raised socially. Offspring were separated at birth into two rearing treatments: (1) raised alone or (2) in a pair. After 1 year, we quantified spatial learning ability of skinks in these rearing treatments (N = 14 solitary, 14 social). We found no effect of rearing treatment on learning ability. The number of skinks to successfully learn the task, the number of trials taken to learn the task, the latency to perform the task, and the number of errors in each trial did not differ between isolated and socially reared skinks. Our results were unexpected, yet the facultative nature of this species' social system may result in a reduced effect of social isolation on behaviour when compared to species with obligate sociality. Overall, our findings do not provide evidence that social environment affects development of spatial learning ability in this family-living lizard.
Publisher: Wiley
Date: 24-03-2015
DOI: 10.1002/ECE3.1447
Publisher: Oxford University Press (OUP)
Date: 28-04-2021
Abstract: While foraging or during social interactions, animals may benefit from judging relative quantity. In iduals may select larger prey or a patch with more food and, likewise, it may pay to track the number and type of in iduals and social interactions. We tested for spontaneous quantity discrimination in the gidgee skink (Egernia stokesii), a family-living lizard. Lizards were presented with food quantities differing in number or size and were able to select the larger quantity of food items when they differed in number but not when items differed in size. We show, for the first time, superior spontaneous discrimination of items differing in number over size in a lizard species, which contrasts with previous findings. Our simple method, however, did not include controls for the use of continuous quantities, and further tests are required to determine the role of such information during quantity discrimination. Our results provide support for the use of the parallel in iduation system for the discrimination of small quantities (four or fewer items). Lizards might, however, still use the approximate number system if items in larger quantities (more than four) are presented. Overall, we uncovered evidence that species might possess specific cognitive abilities potentially adapted to their niche with respect to quantity information (discrete and/or continuous) and the processing system used when judging quantities. Importantly, our results highlight the need for testing multiple species using similar testing procedures to gain a better understanding of the underlying causes leading to differences across species.
Publisher: Elsevier BV
Date: 02-2007
Publisher: JSTOR
Date: 06-1999
DOI: 10.2307/1565735
Publisher: Cambridge University Press
Date: 2018
Publisher: Springer Science and Business Media LLC
Date: 02-06-2017
DOI: 10.1007/S10071-017-1101-Y
Abstract: There is mounting evidence that social learning is not just restricted to group-living animals, but also occurs in species with a wide range of social systems. However, we still have a poor understanding of the factors driving in idual differences in social information use. We investigated the effects of relative dominance on social information use in the eastern water skink (Eul rus quoyii), a species with age-dependent social learning. We used staged contests to establish dominant-subordinate relationships in pairs of lizards and tested whether observers use social information to more quickly solve both an association and reversal learning task in situations where the demonstrator was either dominant or subordinate. Surprisingly, we found no evidence of social information use, irrespective of relative dominance between observer and demonstrator. However, dominant lizards learnt at a faster rate than subordinate lizards in the associative learning task, although there were no significant differences in the reversal task. In light of previous work in this species, we suggest that age may be a more important driver of social information use because demonstrators and observers in our study were closely size-matched and were likely to be of similar age.
Publisher: Cambridge University Press
Date: 12-07-2007
Publisher: Springer Science and Business Media LLC
Date: 12-05-1999
Publisher: MDPI AG
Date: 04-09-2022
Abstract: Colour plays a key role in animal social communication including as an indicator of in idual quality. Using spectrophotometry, we examined colour variation in the throat and venter of the crocodile lizard (Shinisaurus crocodilurus), an endangered species native to southern China and northern Vietnam. We detected two broad colour variants, in iduals with and without red, for each body region and each sex. A cluster analysis of spectral colour measurements (hue, chroma, luminance) revealed discrete throat and ventral morphs when measured in a single snapshot in time. However, photographic evidence revealed that the amount of red relative to body size increased as they got older. In iduals with red were equally likely to be male or female and throat colour was unrelated to ventral colour. Therefore, it is premature to claim that crocodile lizards have discrete colour morphs. We used visual modelling to show that the throat and venter were easily discriminable to a lizard visual system, suggesting they function in social communication. We also asked whether colour variation signalled in idual quality. Females with red throats had greater bite force while males with red throats were older. In addition, females with red venters had larger heads. We also detected differences in morphology linked to colour. Females with red throats had slender bodies and longer tails, while in iduals lacking red on their throats were stouter and had shorter tails. Finally, throat and ventral colour were unrelated to reproductive output (litter size and mass) in females. Males with greater ventral luminance contrast sired offspring from litters with greater litter mass (including stillborns), while males with greater ventral chromatic contrast sired offspring whose collective live mass (excluding stillborns) was greater. Males with greater luminance contrast also sired more live offspring (excluding stillborns). Collectively, these results suggest that male ventral colour signals in idual quality in males. Conservation initiatives should take colour variation into account when planning future captive breeding and release programs for this endangered species.
Publisher: Springer Science and Business Media LLC
Date: 04-08-1999
Publisher: Wiley
Date: 21-10-2016
DOI: 10.1111/JEB.12984
Abstract: Phenotypic traits such as ornaments and armaments are generally shaped by sexual selection, which often favours larger and more elaborate males compared to females. But can sexual selection also influence the brain? Previous studies in vertebrates report contradictory results with no consistent pattern between variation in brain structure and the strength of sexual selection. We hypothesize that sexual selection will act in a consistent way on two vertebrate brain regions that directly regulate sexual behaviour: the medial preoptic nucleus (MPON) and the ventromedial hypothalamic nucleus (VMN). The MPON regulates male reproductive behaviour whereas the VMN regulates female reproductive behaviour and is also involved in male aggression. To test our hypothesis, we used high-resolution magnetic resonance imaging combined with traditional histology of brains in 14 dragon lizard species of the genus Ctenophorus that vary in the strength of precopulatory sexual selection. Males belonging to species that experience greater sexual selection had a larger MPON and a smaller VMN. Conversely, females did not show any patterns of variation in these brain regions. As the volumes of both these regions also correlated with brain volume (BV) in our models, we tested whether they show the same pattern of evolution in response to changes in BV and found that the do. Therefore, we show that the primary brain nuclei underlying reproductive behaviour in vertebrates can evolve in a mosaic fashion, differently between males and females, likely in response to sexual selection, and that these same regions are simultaneously evolving in concert in relation to overall brain size.
Publisher: JSTOR
Date: 06-1999
DOI: 10.2307/1565730
Publisher: Informa UK Limited
Date: 2003
Publisher: Springer Science and Business Media LLC
Date: 04-07-2016
Publisher: Wiley
Date: 27-04-2015
DOI: 10.1111/ETH.12390
Publisher: Informa UK Limited
Date: 04-2003
Publisher: Elsevier BV
Date: 07-2015
DOI: 10.1016/J.CUB.2015.02.070
Abstract: While et al's quick guide to Egernia lizards, a group of social lizards from Austalasia.
Publisher: Elsevier BV
Date: 10-2008
Publisher: JSTOR
Date: 09-1997
DOI: 10.2307/1565660
Publisher: Frontiers Media SA
Date: 10-12-2021
Abstract: There is great ersity in social behavior across the animal kingdom. Understanding the factors responsible for this ersity can help inform theory about how sociality evolves and is maintained. The Australian Tree Skink ( Egernia striolata ) exhibits inter- and intra-population variability in sociality and is therefore a good system for informing models of social evolution. Here, we conducted a multi-year study of a Tree Skink population to describe intra-population variation in the social organization and mating system of this species. Skinks aggregated in small groups of 2–5 in iduals, and these aggregations were typically associated with shared shelter sites (crevices and hollows within rocks and trees). Aggregations were typically made up of one or more adult females and, often, one male and/or juvenile(s). Social network and spatial overlap analyses showed that social associations were strongly biased toward kin. Tree skinks also exhibited high site fidelity regardless of age or sex. There were high levels of genetic monogamy observed with most females (87%) and males (68%) only breeding with a single partner. Our results indicate that Tree Skinks reside in small family groups and are monogamous, which corresponds with existing research across populations. Similar to previous work, our study area consisted of discrete habitat patches (i.e., rock outcrops, trees, or both), which likely limits offspring dispersal and promotes social tolerance between parents and their offspring. Our study clearly demonstrates that there is intra-population variability in Tree Skink social behavior, but it also provides evidence that there is a high degree of inter-population consistency in sociality across their geographic range. We also highlight promising possible avenues for future research, specifically discussing the importance of studying the nature and extent of Tree Skink parental care and quantifying the fitness outcomes of kin-based sociality in this species, which are topics that will further our understanding of the mechanisms underlying variation in vertebrate social behavior.
Publisher: Oxford University Press (OUP)
Date: 2013
Publisher: Oxford University Press (OUP)
Date: 09-05-2013
Publisher: Informa UK Limited
Date: 1997
Publisher: Oxford University Press (OUP)
Date: 18-10-2023
Publisher: Cambridge University Press
Date: 12-07-2007
Publisher: University of Chicago Press
Date: 09-2021
DOI: 10.1086/715976
Publisher: Brill
Date: 1999
Abstract: Two lizard foraging modes, ambush and active foraging, are usually quantified by the variables MPM (movements per minute) and PTM (proportion of time spent moving), but both variables may be affected by behaviors other than foraging. We introduce PAM, the proportion of attacks on prey discovered while lizards are moving (in relation to total attacks). PAM focuses exclusively on foraging behavior. Preliminary data reveal a very high, significant rank correlation between PAM and PTM, and a fairly high, but nonsignificant correlation between PAM and MPM. Collection of PAM data can be very time-consuming. In the absence of PAM, PTM appears to be a superior index of foraging activity to MPM, but all three indices provide valuable information on different aspects of foraging. We additionally present data for four agamine and five gekkonid species from southern Africa. The first quantitative data for agamines (all for Agama) agree with previous qualitative assessments that members of several agamine genera are ambush foragers. All the gekkonids, including three species of Rhotropus and one each of Pachydactylus and Phyllodactylus, are ambush foragers, like most geckos studied to date.
Publisher: Springer Science and Business Media LLC
Date: 28-08-2012
DOI: 10.1007/S00244-012-9795-Y
Abstract: Environmental contaminants from anthropogenic activity such as mining can have profound health effects on the animals living in adjacent areas. We investigated whether inorganic contaminants associated with gold-mining waste discharges were accumulated by a threatened species of lizard, Smaug giganteus, in South Africa. Lizards were s led from two mining sites and two control sites. Blood s les from the most contaminated mining site had significantly greater concentrations of lithium, sodium, aluminum, sulfur, silicon, chromium, manganese, iron, nickel, copper, tungsten, and bismuth than the remaining sites. Contaminant concentrations were not significantly related to lizard body condition, although these relationships were consistently negative. The adult sex ratio of the population inhabiting the most contaminated site also deviated from an expected 1:1 ratio in favour of female lizards. We demonstrate that lizards at these mining sites contained high concentrations of heavy metals that may be imposing as yet poorly understood costs to these lizards.
Publisher: Informa UK Limited
Date: 04-2003
Publisher: University of Chicago Press
Date: 07-2003
DOI: 10.1086/376423
Publisher: Oxford University Press (OUP)
Date: 15-06-2006
Publisher: JSTOR
Date: 06-1994
DOI: 10.2307/1564616
Publisher: Elsevier BV
Date: 06-2006
Publisher: Frontiers Media SA
Date: 15-06-2022
Publisher: The Royal Society
Date: 20-05-2008
Abstract: A crucial problem for most animals is how to deal with multiple types of predator, which differ in their sensory capabilities and methods of prey detection. For animals capable of rapid colour change, one potential strategy is to change their appearance in relation to the threat posed by different predators. Here, we show that the dwarf chameleon, Bradypodion taeniabronchum , exhibits different colour responses to two predators that differ in their visual capabilities. Using a model of animal colour perception to gain a ‘predator's eye view’, we show that chameleons showed better background colour matching in response to birds than snakes, yet they appear significantly more camouflaged to the snake visual system because snakes have poorer colour discrimination.
Publisher: CSIRO Publishing
Date: 28-09-2020
DOI: 10.1071/ZO21017
Abstract: Australian lizards are a erse group distributed across the continent and inhabiting a wide range of environments. Together, they exhibit a remarkable ersity of reproductive morphologies, physiologies, and behaviours that is broadly representative of vertebrates in general. Many reproductive traits exhibited by Australian lizards have evolved independently in multiple lizard lineages, including sociality, complex signalling and mating systems, viviparity, and temperature-dependent sex determination. Australian lizards are thus outstanding model organisms for testing hypotheses about how reproductive traits function and evolve, and they provide an important basis of comparison with other animals that exhibit similar traits. We review how research on Australian lizard reproduction has contributed to answering broader evolutionary and ecological questions that apply to animals in general. We focus on reproductive traits, processes, and strategies that are important areas of current research, including behaviours and signalling involved in courtship mechanisms involved in mating, egg production, and sperm competition nesting and gestation sex determination and finally, birth in viviparous species. We use our review to identify important questions that emerge from an understanding of this body of research when considered holistically. Finally, we identify additional research questions within each topic that Australian lizards are well suited for reproductive biologists to address.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 10-10-2003
Abstract: Lizards Windows to the Evolution of Diversity. by Eric R.Pianka and Laurie J. Vitt. University of California Press, Berkeley, 2003. 347 pp. $45, £29.95. ISBN 0-520-23401-4. Organisms and the Environment. Pianka and Vitt's comprehensive introduction to the ersity of lizards highlights the reptiles' adaptations and their potential as model organisms for evolutionary and ecological studies.
Publisher: S. Karger AG
Date: 2017
DOI: 10.1159/000478738
Abstract: The brain plays a critical role in a wide variety of functions including behaviour, perception, motor control, and homeostatic maintenance. Each function can undergo different selective pressures over the course of evolution, and as selection acts on the outputs of brain function, it necessarily alters the structure of the brain. Two models have been proposed to explain the evolutionary patterns observed in brain morphology. The concerted brain evolution model posits that the brain evolves as a single unit and the evolution of different brain regions are coordinated. The mosaic brain evolution model posits that brain regions evolve independently of each other. It is now understood that both models are responsible for driving changes in brain morphology however, which factors favour concerted or mosaic brain evolution is unclear. Here, we examined the volumes of the 6 major neural sub isions across 14 species of the agamid lizard genus i Ctenophorus /i (dragons). These species have erged multiple times in behaviour, ecology, and body morphology, affording a unique opportunity to test neuroevolutionary models across species. We assigned each species to an ecomorph based on habitat use and refuge type, then used MRI to measure total and regional brain volume. We found evidence for both mosaic and concerted brain evolution in dragons: concerted brain evolution with respect to body size, and mosaic brain evolution with respect to ecomorph. Specifically, all brain sub isions increase in volume relative to body size, yet the tectum and rhombencephalon also show opposite patterns of evolution with respect to ecomorph. Therefore, we find that both models of evolution are occurring simultaneously in the same structures in dragons, but are only detectable when examining particular drivers of selection. We show that the answer to the question of whether concerted or mosaic brain evolution is detected in a system can depend more on the type of selection measured than on the clade of animals studied.
Publisher: Wiley
Date: 13-05-2014
DOI: 10.1111/AEC.12152
Publisher: Wiley
Date: 16-11-2018
DOI: 10.1111/AEC.12670
Publisher: Springer Science and Business Media LLC
Date: 10-09-2003
Publisher: Brill
Date: 11-1999
Publisher: MDPI AG
Date: 11-10-2022
DOI: 10.3390/ANI12202731
Abstract: Crocodile lizards (Shinisaurus crocodilurus) are an endangered, ‘living fossil’ reptile from a monophyletic family and therefore, a high priority for conservation. We constructed climatic models to evaluate the potential impact of climate change on the distribution of crocodile lizards for the period 2000 to 2100 and determined the key environmental factors that affect the dispersal of this endangered species. For the construction of climatic models, we used 985 presence-only data points and 6 predictor variables which showed excellent performance (AUC = 0.974). The three top-ranked factors predicting crocodile lizard distribution were precipitation of the wettest month (bio13, 37.1%), precipitation of the coldest quarter (bio19, 17.9%), and temperature seasonality (bio4, 14.3%). Crocodile lizards were, just as they are now, widely distributed in the north of Guangdong Province in China and Quảng Ninh Province in Vietnam at the last glacial maximum (LGM). Since the LGM, there has been an increase in suitable habitats, particularly in east-central Guangxi Province, China. Under future global warming scenarios, the potential habitat for crocodile lizards is expected to decrease significantly in the next 100 years. Under the most optimistic scenario, only 7.35% to 6.54% of suitable habitat will remain, and under the worst climatic scenario, only 8.34% to 0.86% of suitable habitat will remain. Models for no dispersal and limited dispersal showed that all crocodile lizards would lose habitat as temperatures increase. Our work contributes to an increased understanding of the current and future spatial distribution of the species, supporting practical management and conservation plans.
Publisher: Wiley
Date: 19-09-2017
DOI: 10.1111/JEB.13170
Abstract: Dynamic sexual dichromatism is a temporary colour change between the sexes and has evolved independently in a wide range of anurans, many of which are explosive breeders wherein males physically compete for access to females. Behavioural studies in a few species indicate that dynamic dichromatism functions as a visual signal in large breeding aggregations however, the prevalence of this trait and the social and environmental factors underlying its expression are poorly understood. We compiled a database of 178 anurans with dynamic dichromatism that include representatives from 15 families and subfamilies. Dynamic dichromatism is common in two of the three subfamilies of hylid treefrogs. Phylogenetic comparative analyses of 355 hylid species (of which 95 display dynamic dichromatism) reveal high transition rates between dynamic dichromatism, ontogenetic (permanent) dichromatism and monochromatism reflecting the high evolutionary lability of this trait. Correlated evolution in hylids between dynamic dichromatism and forming large breeding aggregations indicates that the evolution of large breeding aggregations precedes the evolution of dynamic dichromatism. Multivariate phylogenetic logistic regression recovers the interaction between biogeographic distribution and forming breeding aggregations as a significant predictor of dynamic dichromatism in hylids. Accounting for macroecological differences between temperate and tropical regions, such as seasonality and the availability of breeding sites, may improve our understanding of ecological contexts in which dynamic dichromatism is likely to arise in tropical lineages and why it is retained in some temperate species and lost in others.
Publisher: Society for the Study of Amphibians and Reptiles
Date: 12-2012
DOI: 10.1670/10-336
Publisher: Canadian Science Publishing
Date: 02-1996
DOI: 10.1139/Z96-039
Abstract: Using captures in mist nets and monitoring echolocation calls, we quantified bat distribution and activity and measured insect abundance as numbers of insects attracted to black lights at 15-min intervals. These data were collected simultaneously at pairs of sites in riverine and dry woodland savannah along a transect of ca. 350 km from north to south in the Kruger National Park, South Africa. The sites were situated in the north, central, and south of the park and data were collected in January 1993. Our study involved 18 sites, three pairs each in the areas of the Luvuvhu, Letaba, and Sabie rivers. Half of the sites were in riverine woodland, the others in dry woodland. No statistical association exists between bat captures and either bat activity or insect abundance. Bat activity, however, was related significantly to insect abundance. Although bats were significantly more abundant (captures) in riverine habitats than in dry woodland savannah, comparisons of bat ersity and evenness (rarefaction curves, species abundance curves, and Whittaker plots) showed no differences between these habitats. The data neither demonstrate a decline in bat ersity away from the equator nor suggest specific bat communities associated with riverine habitats. The data do demonstrate the important influence of insects on the activity patterns of insectivorous bats.
Publisher: American Society of Ichthyologists and Herpetologists (ASIH)
Date: 12-2002
Publisher: The Royal Society
Date: 20-05-2005
Abstract: Conflict between the sexes has traditionally been studied in terms of costs of mating to females and female resistance. However, courting can also be costly to males, especially when females are larger and aggressively resist copulation attempts. We examined male display intensity towards females in the Cape dwarf chameleon, Bradypodion pumilum , in which females are larger than males and very aggressive. We assessed whether aggressive female rejection imposes potential costs on males and whether males vary their display behaviour with intensity of female rejection, female size or relative size differences. Males persisted in courtship after initial female rejection in 84% of trials, and were bitten in 28% of trials. Attempted mounts were positively associated with males being bitten. Males reduced courtship with increased intensity of female rejection. Male courtship behaviour also varied with female size: males were more likely to court and approach smaller females, consistent with the hypothesis that larger females can inflict more damage. These results suggest that, in addition to assessing female willingness to mate, male dwarf chameleons may use courtship displays to assess potential costs of persistence, including costs associated with aggressive female rejection, weighed against potential reproductive pay-offs associated with forced copulation.
Publisher: Brill
Date: 1999
Abstract: Most lacertids are active foragers, but intrafamilial variation in foraging mode is greater than in most lizard families. We collected data on eight species of African lacertids to assess this variation. Both active and ambush foraging occurred within Pedioplanis and Meroles. Meroles ctenodactylus had a proportion of time moving and proportion of attacked prey detected while moving intermediate to those for actively foraging and ambushing Pedioplanis, but its number of movements per minute was exceptionally high. This species has a unique mixed foraging mode. Like active foragers, it seeks food by tongue-flicking while moving and spends a high percentage of the time moving. Like ambush foragers, it searches visually for prey during pauses between movements. Our findings confirm published data on four Kalahari lacertids. We discuss the history of foraging modes in advanced lacertids.
Publisher: Elsevier BV
Date: 08-2021
Start Date: 03-2013
End Date: 12-2017
Amount: $262,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 12-2021
End Date: 12-2024
Amount: $340,576.00
Funder: Australian Research Council
View Funded ActivityStart Date: 06-2018
End Date: 12-2023
Amount: $300,985.00
Funder: Australian Research Council
View Funded Activity