Michael Bull

Why Is Social Behavior Rare in Reptiles? Lessons From Sleepy Lizards

Publisher: Elsevier

Date: 2017

DOI: 10.1016/BS.ASB.2017.02.001

Successional specialization in a reptile community cautions against widespread planned burning and complete fire suppression

Publisher: Wiley

Date: 20-06-2013

DOI: 10.1111/1365-2664.12119

Social network structure and parasite infection patterns in a territorial reptile, the tuatara (Sphenodon punctatus)

Publisher: Elsevier BV

Date: 11-2010

DOI: 10.1016/J.IJPARA.2010.06.002

Abstract: We investigated whether the parasite load of an in idual could be predicted by its position in a social network. Specifically, we derived social networks in a solitary, territorial reptile (the tuatara, Sphenodon punctatus), with links based on the sharing of space, not necessarily synchronously, in overlapping territories. Tuatara are infected by ectoparasitic ticks (Amblyomma sphenodonti), mites (Neotrombicula spp.) and a blood parasite (Hepatozoon tuatarae) which is transmitted by the tick. We recorded the location of in idual tuatara in two study plots twice daily during the mating season (March) in 2years (2006 and 2007) on Stephens Island, New Zealand. We constructed weighted, directed networks to represent pathways for parasite transmission, where nodes represented in idual tuatara and edges connecting the nodes represented the extent of territory overlap among each pair of in iduals. We considered a network-based hypothesis which predicted that the in-strength of in iduals (the sum of edge weights directed towards a node) in the derived network would be positively related to their parasite load. Alternatively, if the derived social network did not reflect actual parasite transmission, we predicted other factors such as host sex, size or territory size may better explain variation in parasite infection patterns. We found clear positive relationships between the in-strength of tuatara and their tick loads, and infection patterns with tick-borne blood parasites. In particular, the extent that in iduals were connected to males in the network consistently predicted tick loads of tuatara. However, mite loads of tuatara were significantly related to host sex, body size and territory size, and showed little association with network measures. The results suggest that the pathway of transmission of parasites through a population will depend on the transmission mechanism of the parasite, but that social networks provide a powerful predictive tool for some parasites.

Socially interacting or indifferent neighbours? Randomization of movement paths to tease apart social preference and spatial constraints

Publisher: Wiley

Date: 14-04-2016

DOI: 10.1111/2041-210X.12553

Monitoring predation behaviour of the pygmy bluetongue lizard to decide when conservation intervention is needed

Publisher: CSIRO Publishing

Date: 2015

DOI: 10.1071/ZO15021

Abstract: Documenting natural behaviours may be an important component of conservation management of threatened species in that deviations from some behaviours may serve as early warning signs of subsequent deteriorating condition and the possible need for intervention. We described predation behaviour of the endangered Australian scincid lizard Tiliqua adelaidensis from 23 burrows by watching video images from cameras over 10 days each month for five months in spring and summer. We observed 341 predation attempts, of which 277 were successful. These lizards predominantly ambush passing prey from their burrow entrance without completely emerging from the burrow. Orthopterans were the major component of their captures prey captures peaked in November and December. We measured the proportion of unsuccessful foraging attempts, the proportion of foraging attempts that involved full emergence, the mean distance a lizard moved away from the burrow entrance, and the proportion of plant parts in the diet. We suggest that if any of these parameters increase it could indicate the requirement for intervention management. Our study supports the view that behavioural monitoring could be considered as an integral component of any conservation management of endangered animal species.

Refuge sharing network predicts ectoparasite load in a lizard

Publisher: Springer Science and Business Media LLC

Date: 21-05-2010

DOI: 10.1007/S00265-010-0964-6

Determining the success of varying short-term confinement time during simulated translocations of the endangered pygmy bluetongue lizard (Tiliqua adelaidensis)

Publisher: Brill

Date: 2013

DOI: 10.1163/15685381-00002863

Abstract: Translocation is a powerful tool in conservation management, but one of the major problems of this tool is dispersal after release. Translocated animals might disperse from prime habitat and face unsuitable habitat and possible increased exposure to predators. This might lead to decline of a translocated population and could compromise the success of translocation. We assessed whether short-term confinement within enclosures at the translocation site can significantly decrease post release movement, if confinement allowed animals to become familiar with the new habitat, and to overcome handling related stress. We simulated the translocation of an Australian lizard, the endangered pygmy bluetongue lizard Tiliqua adelaidensis , into the centre of a large enclosure and compared the behaviour between in iduals confined to the central region for one or five days before release. We found that lizards confined for five days spent less time basking, and were more likely to disperse than lizards confined for just one day. We suggest that short-term confinement of lizards induces additional stress and that extra days of short-term confinement will not necessarily improve the success of a translocation. Future research could determine the effectiveness of different durations of confinement for releasing animals at translocation sites.

Selection outweighs drift at a fine scale: Lack of MHC differentiation within a family living lizard across geographically close but disconnected rocky outcrops

Publisher: Wiley

Date: 20-04-2018

DOI: 10.1111/MEC.14571

Abstract: The highly polymorphic genes of the major histocompatibility complex (MHC) are involved in disease resistance, mate choice and kin recognition. Therefore, they are widely used markers for investigating adaptive variation. Although selection is the key driver, gene flow and genetic drift also influence adaptive genetic variation, sometimes in opposing ways and with consequences for adaptive potential. To further understand the processes that generate MHC variation, it is helpful to compare variation at the MHC with that at neutral genetic loci. Differences in MHC and neutral genetic variation are useful for inferring the relative influence of selection, gene flow and drift on MHC variation. To date, such investigations have usually been undertaken at a broad spatial scale. Yet, evolutionary and ecological processes can occur at a fine spatial scale, particularly in small or fragmented populations. We investigated spatial patterns of MHC variation among three geographically close, naturally discrete, s ling sites of Egernia stokesii, an Australian lizard. The MHC of E. stokesii has recently been characterized, and there is evidence for historical selection on the MHC. We found E. stokesii MHC weakly differentiated among sites compared to microsatellites, suggesting selection, acting similarly at each site, has outweighed any effects of low gene flow or of genetic drift on E. stokesii MHC variation. Our findings demonstrate the strength of selection in shaping patterns of MHC variation or consistency at a fine spatial scale.

Life history influences how fire affects genetic diversity in two lizard species

Publisher: Wiley

Date: 05-2014

DOI: 10.1111/MEC.12757

Abstract: 'Fire mosaics' are often maintained in landscapes to promote successional ersity in vegetation with little understanding of how this will affect ecological processes in animal populations such as dispersal, social organization and re-establishment. To investigate these processes, we conducted a replicated, spatiotemporal landscape genetics study of two Australian woodland lizard species [Amphibolurus norrisi (Agamidae) and Ctenotus atlas (Scincidae)]. Agamids have a more complex social and territory structure than skinks, so fire might have a greater impact on their population structure and thus genetic ersity. Genetic ersity increased with time since fire in C. atlas and decreased with time since fire in A. norrisi. For C. atlas, this might reflect its increasing population size after fire, but we could not detect increased gene flow that would reduce the loss of genetic ersity through genetic drift. Using landscape resistance analyses, we found no evidence that postfire habitat succession or topography affected gene flow in either species and we were unable to distinguish between survival and immigration as modes of postfire re-establishment. In A. norrisi, we detected female-biased dispersal, likely reflecting its territorial social structure and polygynous mating system. The increased genetic ersity in A. norrisi in recently burnt habitat might reflect a temporary disruption of its territoriality and increased male dispersal, a hypothesis that was supported with a simulation experiment. Our results suggest that the effects of disturbance on genetic ersity will be stronger for species with territorial social organization.

Social networks and the spread of Salmonella in a sleepy lizard population

Publisher: Wiley

Date: 27-07-2012

DOI: 10.1111/J.1365-294X.2012.05653.X

Current insecticide treatments used in locust control have less of a short-term impact on Australian arid-zone reptile communities than does temporal variation

Publisher: CSIRO Publishing

Date: 2015

DOI: 10.1071/WR14194

Abstract: Context Despite the regular use of pesticides to control locusts, there is a lack of information on the effects of locust-control treatments on reptiles worldwide. Exposure to pesticides poses a significant potential hazard to small reptiles, both from the direct effects of exposure, and indirectly because of their largely insectivorous diet and small home ranges. Aims Our study aimed to monitor the effects of two insecticides applied operationally for locust control in Australia. A phenyl pyrazole pesticide, fipronil, and a fungal biopesticide, Metarhizium acridium (Green Guard®), were applied aerially in either a barrier or block treatment in the absence of dense locust populations, and effects on non-target arid-zone reptiles were measured. Methods We monitored reptile-abundance and community-composition responses to treatments using a large field-based pitfall-trapping experiment, with replicated control and spraying treatments, which approximated the scale of aerial-based locust-control operations in Australia. Key results Neither reptile abundance nor community composition was significantly affected by locust-control treatments. However, both abundance and community composition as detected by pitfall trapping changed over time, in both control and treatment plots, possibly as a result of a decrease in annual rainfall. Conclusions The absence of any significant short-term pesticide treatment effects in our study suggests that the two locust-control application methods studied present a relatively insignificant hazard to reptiles at our site, based on a single application. Similar to other areas of Australia, climate and other factors are likely to be stronger drivers of reptile abundance and community structure. Implications Monitoring over an area that approximates the scale of the current locust-control operations is an important step in understanding the possible effects of current pesticide exposure on reptile populations and will inform insecticide risk assessments in Australia. However, important information on the immediate response of in iduals to insecticide application and long-term effects of exposure are missing. The preliminary research reported in the present paper should be complemented by future investigations on long-term and sublethal impacts of pesticide exposure on Australian native reptiles and the possible benefits provided to reptiles by the resource pulses represented in untreated high-density locust populations.

Resources and their distribution can influence social behaviour at translocation sites: Lessons from a lizard

Publisher: Elsevier BV

Date: 07-2014

DOI: 10.1016/J.APPLANIM.2014.04.013

The impact of sheep grazing on the depth of spider burrows and of burrows selected by the pygmy bluetongue lizard (Tiliqua adelaidensis)

Publisher: CSIRO Publishing

Date: 2016

DOI: 10.1071/WR16138

Abstract: Context Grazing by domestic stock can potentially influence ecosystems positively or negatively, depending on the grazing regime and intensity. The pygmy bluetongue lizard (Tiliqua adelaidensis) is an endangered species, restricted to fragmented grasslands in the Mid North region of South Australia, predominantly grazed by sheep. These lizards refuge in vertical burrows. They do not dig their own burrows, instead relying on co-existing spiders for this essential resource. Aims We investigated how sheep grazing influenced spider burrows, and predicted the following: that grazing sheep might tr le and destroy shallow burrows that burrows in grazed habitat with less vegetative cover would have higher temperatures in summer and that, by way of compensation, spiders would dig deeper burrows in grazed habitat. Methods We monitored 12 30m×30m plots monthly, over two austral spring/summer periods (September–March 2012–14). We recorded the number, depth and occupant of all spider burrows in those plots in each survey. We also measured temperatures inside artificial burrows in grazed and ungrazed habitat over a 3-day period in September 2014. Key results Mean burrow depth increased with grazing. This was not because in idual burrows became deeper, but because the shallowest burrows were lost where there were sheep. Burrows were significantly hotter in grazed habitat, but lizards consistently chose deeper, cooler burrows. In the subset of burrows that were occupied by lizards, there was no difference in depth between grazed and ungrazed treatments. We detected no difference in spider digging activity between grazed and ungrazed plots. Conclusions Sheep grazing can destroy shallow burrows, probably through tr ling, and because sheep produce burrow filling debris. However, grazing did not affect deeper burrows occupied by pygmy bluetongue lizards. Implications This short study indicated that moderate levels of grazing have low impact on deeper burrows suitable for pygmy bluetongue lizards and for lizard persistence. It explains how sheep and lizards have co-occurred for so long, but leaves open the question of how the loss of shallow burrows affects populations of the burrow-digging spiders that are an essential component of the lizard environment.

Roadside connectivity does not increase reptile abundance or richness in a fragmented mallee landscape

Publisher: Wiley

Date: 05-09-2011

DOI: 10.1111/J.1442-9993.2011.02292.X

Lizards with rhythm? Multi-day patterns in total daily movement

Publisher: Wiley

Date: 26-02-2008

DOI: 10.1111/J.1469-7998.2008.00413.X

Associations between blood parasite infection and a microsatellite DNA allele in an Australian scincid lizard (Egernia stokesii)

Publisher: Springer Science and Business Media LLC

Date: 07-07-2006

DOI: 10.1007/S00436-006-0254-4

Abstract: We used blood s les from 175 in iduals of the Australian lizard Egernia stokesii to determine infection status of three apicomplexan blood parasites from the genera Hemolivia, Schellackia, and Plasmodium and to determine genotypes at 12 microsatellite DNA loci. We found one significant association between genotype and infection status. For locus Est4, in iduals carrying allele 159 had lower prevalence of infection with Hemolivia (14.3% of 28 lizards) than in iduals that did not carry the allele (58.4% of 89 lizards). We interpret this as a linkage to a functional gene associated with parasite resistance. We found no evidence among seven lizard populations that the frequency of allele 159 was related to the population prevalence of Hemolivia infection and discuss several explanations of that pattern.

Genes and group membership predict Gidgee skink (Egernia stokesii) reproductive pairs

Publisher: Oxford University Press (OUP)

Date: 20-04-2017

DOI: 10.1093/JHERED/ESX026

Abstract: Due to their role in mate choice, disease resistance and kin recognition, genes of the major histocompatibility complex (MHC) are good candidates for investigating genetic-based mate choice. MHC-based mate choice is context dependent and influenced by many factors including social structure. Social structure ersity makes the Egernia group of lizards suitable for comparative studies of MHC-based mate choice. We investigated mate choice in the gidgee skink (Egernia stokesii), a lizard that exhibits high levels of social group and spatial stability. Group membership was incorporated into tests of the good genes as heterozygosity and compatible genes hypotheses for adaptive (MHC) and neutral (microsatellite) genetic ersity (n = 47 in iduals genotyped). Females were more likely to pair with a male with higher MHC ersity and with whom they had a lower degree of microsatellite relatedness. Males were more likely to pair with a female with higher microsatellite heterozygosity and with whom they shared a lower proportion of MHC alleles. Lizards were more likely to mate with an in idual from within, rather than outside, their social group, which confirmed earlier findings for this species and indicated mate choice had already largely occurred prior to either social group formation or acceptance of an in idual into an existing group. Thus, a combination of genes and group membership, rather than group membership alone, predicted mate choice in this species. This work will contribute to an enhanced understanding of squamate group formation and a deeper understanding of the evolution of sociality within all vertebrates.

When the going gets tough: behavioural type-dependent space use in the sleepy lizard changes as the season dries

Publisher: The Royal Society

Date: 22-11-2015

DOI: 10.1098/RSPB.2015.1768

Abstract: Understanding space use remains a major challenge for animal ecology, with implications for species interactions, disease spread, and conservation. Behavioural type (BT) may shape the space use of in iduals within animal populations. Bolder or more aggressive in iduals tend to be more exploratory and disperse further. Yet, to date we have limited knowledge on how space use other than dispersal depends on BT. To address this question we studied BT-dependent space-use patterns of sleepy lizards ( Tiliqua rugosa ) in southern Australia. We combined high-resolution global positioning system (GPS) tracking of 72 free-ranging lizards with repeated behavioural assays, and with a survey of the spatial distributions of their food and refuge resources. Bayesian generalized linear mixed models (GLMM) showed that lizards responded to the spatial distribution of resources at the neighbourhood scale and to the intensity of space use by other conspecifics (showing apparent conspecific avoidance). BT (especially aggressiveness) affected space use by lizards and their response to ecological and social factors, in a seasonally dependent manner. Many of these effects and interactions were stronger later in the season when food became scarce and environmental conditions got tougher. For ex le, refuge and food availability became more important later in the season and unaggressive lizards were more responsive to these predictors. These findings highlight a commonly overlooked source of heterogeneity in animal space use and improve our mechanistic understanding of processes leading to behaviourally driven disease dynamics and social structure.

Visual conspecific cues will not help in pygmy bluetongue lizard translocations

Publisher: Elsevier BV

Date: 02-2014

DOI: 10.1016/J.APPLANIM.2013.11.005

Dispersal responses override density effects on genetic diversity during post-disturbance succession

Publisher: The Royal Society

Date: 30-03-2016

DOI: 10.1098/RSPB.2015.2934

Abstract: Dispersal fundamentally influences spatial population dynamics but little is known about dispersal variation in landscapes where spatial heterogeneity is generated predominantly by disturbance and succession. We tested the hypothesis that habitat succession following fire inhibits dispersal, leading to declines over time in genetic ersity in the early successional gecko Nephrurus stellatus . We combined a landscape genetics field study with a spatially explicit simulation experiment to determine whether successional patterns in genetic ersity were driven by habitat-mediated dispersal or demographic effects (declines in population density leading to genetic drift). Initial increases in genetic structure following fire were likely driven by direct mortality and rapid population expansion. Subsequent habitat succession increased resistance to gene flow and decreased dispersal and genetic ersity in N. stellatus . Simulated changes in population density alone did not reproduce these results. Habitat-mediated reductions in dispersal, combined with changes in population density, were essential to drive the field-observed patterns. Our study provides a framework for combining demographic, movement and genetic data with simulations to discover the relative influence of demography and dispersal on patterns of landscape genetic structure. Our results suggest that succession can inhibit connectivity among in iduals, opening new avenues for understanding how disturbance regimes influence spatial population dynamics.

Lovers and fighters in sleepy lizard land: where do aggressive males fit in a social network?

Publisher: Elsevier BV

Date: 2012

DOI: 10.1016/J.ANBEHAV.2011.10.028

Isolation and characterisation of microsatellites for the endangered Slater’s skink, Liopholis slateri (Squamata : Scincidae), via next-generation sequencing

Publisher: CSIRO Publishing

Date: 2017

DOI: 10.1071/ZO17053

Abstract: We characterised 14 new polymorphic microsatellite loci for the endangered lizard Liopholis slateri. Initially, 454 shotgun sequencing was used to identify 46 loci, which were trialled for lification. Subsequently, 14 of these loci were screened for variation in 21 in iduals from scat-derived DNA s les collected from Owen Springs Reserve in central Australia. All 14 loci were polymorphic, with observed heterozygosity ranging from 0.19 to 0.86 and the number of alleles per locus ranging from 2 to 10. These loci will be useful in understanding the genetic variation and connectivity within and among extant L. slateri populations.

Transmission mode and distribution of parasites among groups of the social lizard Egernia stokesii

Publisher: Springer Science and Business Media LLC

Date: 16-03-2006

DOI: 10.1007/S00436-005-0120-9

Abstract: We explored patterns of infection of three apicomplexan blood parasites with different transmission mechanisms in 46 social groups across seven populations of the Australian lizard, Egernia stokesii. There was higher aggregation of infections within social groups for Hemolivia, transmitted by ticks, and Schellackia, either tick-transmitted or directly transmitted from mother to offspring, than for Plasmodium, with more mobile dipteran vectors. Prevalence was not related to group size, proximity to other groups or spatial overlap with adjacent groups for any of the parasites. However, for Hemolivia, groups with higher levels of relatedness among adults had higher parasite prevalence. Living in social groups leads to higher risk of infection for parasites with low transmission mobility. An unanswered question is why so few lizard species tolerate these risks to form stable social aggregations.

Interactions between pygmy bluetongue lizards and co-existing species

Publisher: Informa UK Limited

Date: 14-06-2015

DOI: 10.1080/03721426.2015.1051644

Unravelling causality from correlations: revealing the impacts of endemic ectoparasites on a protected species (tuatara)

Publisher: Cambridge University Press (CUP)

Date: 16-10-2009

DOI: 10.1017/S0031182009991314

Abstract: Understanding the impacts of endemic parasites on protected hosts is an essential element of conservation management. However, where manipulative experiments are unethical, causality cannot be inferred from observational correlative studies. Instead, we used an experimental structure to explore temporal associations between body condition of a protected reptile, the tuatara ( Sphenodon punctatus ) and infestation with ectoparasites (ticks and mites). We surveyed tuatara in a mark-recapture study on Stephens Island (New Zealand), which encompassed the pre-peak, peak and post-peak infestation periods for each ectoparasite. Tick loads during the peak infestation period were negatively related to body condition of tuatara. Body condition before the peak was not related to subsequent infestation rates however, tick loads in the peak were negatively related to subsequent changes in body condition. Mite loads during the peak infestation period were not correlated with body condition of tuatara. Body condition before the peak had no effect on subsequent mite infestation rates, but mite loads of small males during the peak were negatively related to subsequent changes in body condition. Our results suggest that both ectoparasites reduce the body condition of tuatara, which has implications for the long-term conservation management of this host and its parasites.

Managed relocation as an adaptation strategy for mitigating climate change threats to the persistence of an endangered lizard

Publisher: Wiley

Date: 12-06-2012

DOI: 10.1111/J.1365-2486.2012.02742.X

Abstract: The distributional ranges of many species are contracting with habitat conversion and climate change. For vertebrates, informed strategies for translocations are an essential option for decisions about their conservation management. The pygmy bluetongue lizard, Tiliqua adelaidensis, is an endangered reptile with a highly restricted distribution, known from only a small number of natural grassland fragments in South Australia. Land-use changes over the last century have converted perennial native grasslands into croplands, pastures and urban areas, causing substantial contraction of the species' range due to loss of essential habitat. Indeed, the species was thought to be extinct until its rediscovery in 1992. We develop coupled-models that link habitat suitability with stochastic demographic processes to estimate extinction risk and to explore the efficacy of potential climate adaptation options. These coupled-models offer improvements over simple bioclimatic envelope models for estimating the impacts of climate change on persistence probability. Applying this coupled-model approach to T. adelaidensis, we show that: (i) climate-driven changes will adversely impact the expected minimum abundance of populations and could cause extinction without management intervention, (ii) adding artificial burrows might enhance local population density, however, without targeted translocations this measure has a limited effect on extinction risk, (iii) managed relocations are critical for safeguarding lizard population persistence, as a sole or joint action and (iv) where to source and where to relocate animals in a program of translocations depends on the velocity, extent and nonlinearities in rates of climate-induced habitat change. These results underscore the need to consider managed relocations as part of any multifaceted plan to compensate the effects of habitat loss or shifting environmental conditions on species with low dispersal capacity. More broadly, we provide the first step towards a more comprehensive framework for integrating extinction risk, managed relocations and climate change information into range-wide conservation management.

Scatting behaviour of the pygmy bluetongue lizard

Publisher: Brill

Date: 2016

DOI: 10.1163/15685381-00003045

Abstract: We used video recordings of 29 pygmy bluetongue lizards for ten days of each month during their spring and summer activity season to observe scatting behaviour. This was possible because resident lizards rarely moved from their single entrance burrows. We used these observations to ask questions about social communication that might be relevant to conservation of this endangered species. We found lizards produced more scats in the middle of the day than earlier or later in the day, and more scats in the spring and early summer than later in the summer. Lizards moved an average of 68.54 ± 0.09 cm from their burrow entrance to deposit scats, taking an average of 2.4 min per defecation trip. They tended to use the same path direction for most defecation trips, but used more different directions if there were more close neighbours, strongly supporting a hypothesis that scats mark burrow ownership. The results suggested that conservation managers might reduce stress for relocated lizards by removing scat piles in the early stages of settlement.

Contemplating the future: Acting now on long-term monitoring to answer 2050's questions

Publisher: Wiley

Date: 07-01-2015

DOI: 10.1111/AEC.12207

Testing the robustness of transmission network models to predict ectoparasite loads. One lizard, two ticks and four years

Publisher: Elsevier BV

Date: 12-2013

DOI: 10.1016/J.IJPPAW.2013.09.005

The response of a sleepy lizard social network to altered ecological conditions

Publisher: Elsevier BV

Date: 10-2013

DOI: 10.1016/J.ANBEHAV.2013.07.016

Spatial Variation and Survival of Salmonella enterica Subspecies in a Population of Australian Sleepy Lizards (Tiliqua rugosa)

Publisher: American Society for Microbiology

Date: 09-2015

DOI: 10.1128/AEM.00997-15

Abstract: The life cycles of many enteric bacterial species require a transition between two very distinct environments. Their primary habitat is the gastrointestinal tract of the host, while their secondary habitat, during transmission from one host to another, consists of environments external to the host, such as soil, water, and sediments. Consequently, both host and environmental factors shape the genetic structure of enteric bacterial populations. This study examined the distribution of four Salmonella enterica subspecies in a population of sleepy lizards, Tiliqua rugosa , in a semiarid region of South Australia. The lizards living within the 1,920-m by 720-m study site were radio tracked, and their enteric bacteria were s led at regular intervals throughout their active seasons in the years 2001, 2002, and 2006. Four of the six subspecies of S. enterica were present in this population and were nonrandomly distributed among the lizards. In particular, S. enterica subsp. diarizonae was restricted to lizards living in the most shaded parts of the study site with an overstorey of Casuarina trees. Experiments undertaken to investigate the survival of S. enterica cells under seminatural conditions revealed that cell survival decreased with increased exposure to elevated temperatures and UV light. Among the three S. enterica subspecies tested, S. enterica subsp. diarizonae consistently had an average expected life span that was shorter than that observed for the other two subspecies. There was no indication in the data that there was any competitive dominance hierarchy among the S. enterica subspecies within in idual hosts. Thus, the nonrandom distribution of S. enterica subspecies in this population of lizards appears to be driven by their different survival characteristics in the external environment.

The impact of sheep grazing on burrows for pygmy bluetongue lizards and on burrow digging spiders

Publisher: Wiley

Date: 16-04-2015

DOI: 10.1111/JZO.12247

Ocular Anatomy and Retinal Photoreceptors in a Skink, the Sleepy Lizard (Tiliqua rugosa)

Publisher: Wiley

Date: 31-07-2012

DOI: 10.1002/AR.22546

Abstract: The Australian sleepy lizard (Tiliqua rugosa) is a large day-active skink which occupies stable overlapping home ranges and maintains long-term monogamous relationships. Its behavioral ecology has been extensively studied, making the sleepy lizard an ideal model for investigation of the lizard visual system and its specializations, for which relatively little is known. We examine the morphology, density, and distribution of retinal photoreceptors and describe the anatomy of the sleepy lizard eye. The sleepy lizard retina is composed solely of photoreceptors containing oil droplets, a characteristic of cones. Two groups could be distinguished single cones and double cones, consistent with morphological descriptions of photoreceptors in other diurnal lizards. Although all photoreceptors were cone-like in morphology, a subset of photoreceptors displayed immunoreactivity to rhodopsin-the visual pigment of rods. This finding suggests that while the morphological properties of rod photoreceptors have been lost, photopigment protein composition has been conserved during evolutionary history.

Egernia stokesii (gidgee skink) MHC I positively selected sites lack concordance with HLA peptide binding regions

Publisher: Springer Science and Business Media LLC

Date: 12-08-2016

DOI: 10.1007/S00251-016-0947-5

Abstract: Genes of the major histocompatibility complex (MHC) play an important role in vertebrate disease resistance, kin recognition and mate choice. Mammalian MHC is the most widely characterised of all vertebrates, and attention is often given to the peptide binding regions of the MHC because they are presumed to be under stronger selection than non-peptide binding regions. For vertebrates where the MHC is less well understood, researchers commonly use the amino acid positions of the peptide binding regions of the human leukocyte antigen (HLA) to infer the peptide binding regions within the MHC sequences of their taxon of interest. However, positively selected sites within MHC have been reported to lack correspondence with the HLA in fish, frogs, birds and reptiles including squamates. Despite squamate ersity, the MHC has been characterised in few snakes and lizards. The Egernia group of scincid lizards is appropriate for investigating mechanisms generating MHC variation, as their inclusion will add a new lineage (i.e. Scincidae) to studies of selection on the MHC. We aimed to identify positively selected sites within the MHC of Egernia stokesii and then determine if these sites corresponded with the peptide binding regions of the HLA. Six positively selected sites were identified within E. stokesii MHC I, only two were homologous with the HLA. E. stokesii positively selected sites corresponded more closely to non-lizard than other lizard taxa. The characterisation of the MHC of more intermediate taxa within the squamate order is necessary to understand the evolution of the MHC across all vertebrates.

Fine scale genetic structure in a population of the Prehensile Tailed Skink, Corucia zebrata

Publisher: Society for the Study of Amphibians and Reptiles

Date: 06-2013

DOI: 10.1670/11-234

Development of microsatellite markers and analysis of their inheritance in the Australian reptile tick, Bothriocroton hydrosauri

Publisher: Wiley

Date: 03-2017

DOI: 10.1111/J.1471-8286.2007.01987.X

Abstract: Despite long-term study, the mechanism explaining the parapatric distribution of two Australian reptile tick species is not understood. We describe the development of primers lifying 10 microsatellite Bothriocroton hydrosauri loci, for the study of population structure and dispersal patterns of this tick. The numbers of alleles per locus ranged from two to seven in ticks from the study site, and the observed heterozygosity between 0.28 and 0.69. Pedigree analysis indicates that one locus is inherited in a non-Mendelian manner in three families, which was not explained by null allele presence.

Low prevalence of Salmonella enterica in Australian wildlife

Publisher: Wiley

Date: 22-03-2010

DOI: 10.1111/J.1758-2229.2010.00152.X

Abstract: A total of 2489 wildlife hosts from Australia were s led in order to determine the fraction of hosts that harboured Salmonella enterica as a dominant member of the host's enteric community. Hosts s led included fish, frogs, reptiles, birds and mammals from the four main climatic regions of Australia: desert, grassland, temperate and tropical. Salmonella enterica was predominately isolated from reptiles, in particular, lizards. It was also isolated from mammals, though not from any fish, frog or bird host. Salmonella enterica was more likely to be isolated from lizards living in desert or grassland regions of Australia compared with lizards inhabiting tropical or temperate regions. The low prevalence of S. enterica isolated from wildlife hosts in Australia indicates that Australian wildlife are unlikely to play a large role in disseminating S. enterica to humans and livestock.

Using plant distributions to predict the current and future range of a rare lizard

Publisher: Wiley

Date: 30-01-2201

DOI: 10.1111/DDI.12050

Mate Familiarity Affects Pairing Behaviour in a Long‐Term Monogamous Lizard: Evidence from Detailed Bio‐Logging and a 31‐Year Field Study

Publisher: Wiley

Date: 27-04-2015

DOI: 10.1111/ETH.12390

Association networks reveal social organization in the sleepy lizard

Publisher: Elsevier BV

Date: 2010

DOI: 10.1016/J.ANBEHAV.2009.11.002

Non-invasive lizard identification using signature curves

Publisher: IEEE

Date: 11-2009

DOI: 10.1109/TENCON.2009.5395852

Value of long‐term ecological studies

Publisher: Wiley

Date: 23-02-2012

DOI: 10.1111/J.1442-9993.2011.02351.X

Clustering of related individuals in a population of the Australian lizard, Egernia frerei

Publisher: Wiley

Date: 04-03-2005

DOI: 10.1111/J.1365-294X.2005.02478.X

Developmental stages and molecular phylogeny of Hepatozoon tuatarae, a parasite infecting the New Zealand tuatara, Sphenodon punctatus and the tick, Amblyomma sphenodonti

Publisher: Elsevier BV

Date: 09-2010

DOI: 10.1016/J.IJPARA.2010.03.018

Abstract: The developmental stages of Hepatozoon tuatarae were elucidated in both the tuatara host, Sphenodon punctatus and the tick, Amblyomma sphenodonti. PCR licons from A. sphenodonti s les identified DNA matching H. tuatarae. Dissection of tick s les showed oogenesis and sporogony occurring in the haemocoel of A. sphenodonti with the average mature oocyst size being 236 x 228 microm. Partial sequence data of the parasite's small subunit ribosomal gene, obtained by PCR, was used for phylogenetic comparison. Characterisation of the H. tuatarae lifecycle will help in conservation management of the tuatara.

Human disturbance and stride frequency in the sleepy lizard (Tiliqua rugosa): implications for behaviour studies

Publisher: Society for the Study of Amphibians and Reptiles

Date: 12-2004

DOI: 10.1670/13-04A

Seasonal and spatial dynamics of ectoparasite infestation of a threatened reptile, the tuatara (Sphenodon punctatus)

Publisher: Wiley

Date: 21-11-2008

DOI: 10.1111/J.1365-2915.2008.00751.X

Abstract: The conservation of threatened vertebrate species and their threatened parasites requires an understanding of the factors influencing their distribution and dynamics. This is particularly important for species maintained in conservation reserves at high densities, where increased contact among hosts could lead to increased rates of parasitism. The tuatara (Sphenodon punctatus) (Reptilia: Sphenodontia) is a threatened reptile that persists at high densities in forests (approximately 2700 tuatara/ha) and lower densities in pastures and shrubland (< 200 tuatara/ha) on Stephens Island, New Zealand. We investigated the lifecycles and seasonal dynamics of infestation of two ectoparasites (the tuatara tick, Amblyomma sphenodonti, and trombiculid mites, Neotrombicula sp.) in a mark-recapture study in three forest study plots from November 2004 to March 2007, and compared infestation levels among habitat types in March 2006. Tick loads were lowest over summer and peaked from late autumn (May) until early spring (September). Mating and engorgement of female ticks was highest over spring, and larval tick loads subsequently increased in early autumn (March). Nymphal tick loads increased in September, and adult tick loads increased in May. Our findings suggest the tuatara tick has a 2- or 3-year lifecycle. Mite loads were highest over summer and autumn, and peaked in March. Prevalences (proportion of hosts infected) and densities (estimated number of parasites per hectare) of ticks were similar among habitats, but tick loads (parasites per host) were higher in pastures than in forests and shrub. The prevalence and density of mites was higher in forests than in pasture or shrub, but mite loads were similar among habitats. We suggest that a higher density of tuatara in forests may reduce the ectoparasite loads of in iduals through a dilution effect. Understanding host-parasite dynamics will help in the conservation management of both the host and its parasites.

The influence of refuge sharing on social behaviour in the lizard Tiliqua rugosa

Publisher: Springer Science and Business Media LLC

Date: 03-11-2010

DOI: 10.1007/S00265-010-1087-9

Behavioural changes in an endangered grassland lizard resulting from simulated agricultural activities

Publisher: Elsevier BV

Date: 02-2015

DOI: 10.1016/J.JARIDENV.2014.10.004

Substructure within Salmonella enterica subsp. enterica Isolates from Australian Wildlife

Publisher: American Society for Microbiology

Date: 05-2011

DOI: 10.1128/AEM.02764-10

Abstract: Multilocus sequence typing of 56 Salmonella enterica subsp. enterica strains isolated from Australian wildlife hosts was performed. The results of population assignment algorithms revealed that the 56 strains could be sub ided into two distinct clades. Strains belonging to the two clades were further distinguished phenotypically, genotypically, and with respect to host distribution.

Short-Term Dispersal Response of an Endangered Australian Lizard Varies with Time of Year

Publisher: Public Library of Science (PLoS)

Date: 22-08-2014

DOI: 10.1371/JOURNAL.PONE.0106002

Post-fire succession affects abundance and survival but not detectability in a knob-tailed gecko

Publisher: Elsevier BV

Date: 2012

DOI: 10.1016/J.BIOCON.2011.10.023

Food supplementation reduces post-release dispersal during simulated translocation of the Endangered pygmy bluetongue lizard Tiliqua adelaidensis 

Publisher: Inter-Research Science Center

Date: 16-08-2012

DOI: 10.3354/ESR00446

Network structure and parasite transmission in a group living lizard, the gidgee skink, Egernia stokesii

Publisher: Springer Science and Business Media LLC

Date: 02-04-2009

DOI: 10.1007/S00265-009-0730-9

Isolation of microsatellite loci from a social lizard, Egernia stokesii, using a modified enrichment procedure

Publisher: Oxford University Press (OUP)

Date: 03-1999

DOI: 10.1093/JHERED/90.2.301

Minimizing the cost of translocation failure with decision‐tree models that predict species’ behavioral response in translocation sites

Publisher: Wiley

Date: 03-03-2015

DOI: 10.1111/COBI.12479

Abstract: The high number of failures is one reason why translocation is often not recommended. Considering how behavior changes during translocations may improve translocation success. To derive decision‐tree models for species’ translocation, we used data on the short‐term responses of an endangered Australian skink in 5 simulated translocations with different release conditions. We used 4 different decision‐tree algorithms (decision tree, decision‐tree parallel, decision stump, and random forest) with 4 different criteria (gain ratio, information gain, gini index, and accuracy) to investigate how environmental and behavioral parameters may affect the success of a translocation. We assumed behavioral changes that increased dispersal away from a release site would reduce translocation success. The trees became more complex when we included all behavioral parameters as attributes, but these trees yielded more detailed information about why and how dispersal occurred. According to these complex trees, there were positive associations between some behavioral parameters, such as fight and dispersal, that showed there was a higher chance, for ex le, of dispersal among lizards that fought than among those that did not fight. Decision trees based on parameters related to release conditions were easier to understand and could be used by managers to make translocation decisions under different circumstances. Minimizar el Costo del Fracaso de la Reubicación con Modelos de Árboles de Decisión que Predigan la Respuesta Conductual de la Especie en los Sitios de Reubicación

High levels of genetic monogamy in the group-living Australian lizard Egernia stokesii

Publisher: Wiley

Date: 09-2002

DOI: 10.1046/J.1365-294X.2002.01552.X

Abstract: The Australian lizard Egernia stokesii lives in spatially and temporally stable groups of up to 17 in iduals. We have recently shown that these groups are comprised of breeding partners, their offspring and, in some cases, highly related adults, providing the first genetic evidence of a family structure in any lizard species. Here we investigated the mating system of E. stokesii using data from up to eight polymorphic microsatellite loci and tested the hypothesis that breeding partners are monogamous both within and between mating seasons. Among 16 laboratory-born litters from field collected gravid females from two sites in South Australia, 75% had a single male parent and no male contributed to more than one litter, indicating a high level of genetic monogamy within a season. Additional analyses of field caught in iduals, captured between 1994 and 1998, enabled assignment of parentage for 70 juveniles and subadults. These data showed that most young (88.6%) had both parents from within the same group and that high proportions of males (88.9%) and females (63.6%) have multiple cohorts of offspring only with the same partner. Our results suggest that monogamy both within and between seasons is a common mating strategy of E. stokesii and that breeding partners maintain stable associations together and with multiple cohorts of their offspring over periods of up to at least 5 years.

A contact-based social network of lizards is defined by low genetic relatedness among strongly connected individuals

Publisher: Elsevier BV

Date: 11-2014

DOI: 10.1016/J.ANBEHAV.2014.08.019

Molecular genetic data provide support for a model of transmission dynamics in an Australian reptile tick, Bothriocroton hydrosauri

Publisher: Wiley

Date: 2009

DOI: 10.1111/J.1365-294X.2008.04023.X

Larger lizards live longer in the group-living Egernia stokesii

Publisher: CSIRO Publishing

Date: 2016

DOI: 10.1071/ZO16024

Abstract: Animal space use has implications for gene flow, disease dynamics, mating systems and the evolution of sociality. Given recent attention to sociality in reptiles, lizards are an important group for expanding our understanding of animal space use. Lizard space use is commonly investigated within one population over a short period and limited attention has been given to potential predictors of site fidelity. This study evaluated site fidelity in three populations of group-living Egernia stokesii (gidgee skink) between two field surveys separated by almost a decade. Of 43 recaptured lizards, 28 (65%) occupied their original space, and 15 (36%) of those shared their space with the same other lizard or lizards in both surveys. This confirmed long-term site and social bond fidelity in E. stokesii. We found that larger lizards were more likely to be recaptured. Neither body size, in idual genetic heterozygosity, nor the availability of refuges strongly predicted whether lizards were recaptured in the same or a different place. The reasons why some lizards stayed in the same space while others moved are yet to be resolved.

Artificial Water Point for Livestock Influences Spatial Ecology of a Native Lizard Species

Publisher: Public Library of Science (PLoS)

Date: 22-01-2016

DOI: 10.1371/JOURNAL.PONE.0147433

Environment modulates population social structure: experimental evidence from replicated social networks of wild lizards

Publisher: Elsevier BV

Date: 2016

DOI: 10.1016/J.ANBEHAV.2015.10.001

Lizard movement tracks: variation in path re-use behaviour is consistent with a scent-marking function

Publisher: PeerJ

Date: 22-03-2016

DOI: 10.7717/PEERJ.1844

Abstract: In idual movement influences the spatial and social structuring of a population. Animals regularly use the same paths to move efficiently to familiar places, or to patrol and mark home ranges. We found that Australian sleepy lizards ( Tiliqua rugosa ), a monogamous species with stable pair-bonds, repeatedly used the same paths within their home ranges and investigated whether path re-use functions as a scent-marking behaviour, or whether it is influenced by site familiarity. Lizards can leave scent trails on the substrate when moving through the environment and have a well-developed vomeronasal system to detect and respond to those scents. Path re-use would allow sleepy lizards to concentrate scent marks along these well-used trails, advertising their presence. Hypotheses of mate attraction and mating competition predict that sleepy lizard males, which experience greater intra-sexual competition, mark more strongly. Consistent with those hypotheses, males re-used their paths more than females, and lizards that showed pairing behaviour with in iduals of the opposite sex re-used paths more than unpaired lizards, particularly among females. Hinterland marking is most economic when home ranges are large and mobility is low, as is the case in the sleepy lizard. Consistent with this strategy, re-used paths were predominantly located in the inner 50% home range areas. Together, our detailed movement analyses suggest that path re-use is a scent marking behaviour in the sleepy lizard. We also investigated but found less support for alternative explanations of path re-use behaviour, such as site familiarity and spatial knowledge. Lizards established the same number of paths, and used them as often, whether they had occupied their home ranges for one or for more years. We discuss our findings in relation to maintenance of the monogamous mating system of this species, and the spatial and social structuring of the population.

Primers for novel microsatellite markers in “fire-specialist” lizards (Amphibolurus norrisi, Ctenotus atlas and Nephrurus stellatus) and their performance across multiple populations

Publisher: Springer Science and Business Media LLC

Date: 16-12-2010

DOI: 10.1007/S12686-010-9359-2

Phylogeography of the prehensile-tailed skink Corucia zebrata on the Solomon Archipelago

Publisher: Wiley

Date: 17-05-2012

DOI: 10.1002/ECE3.84

MHC genotyping from next-generation sequencing: detailed methodology for the gidgee skink, Egernia stokesii

Publisher: Informa UK Limited

Date: 02-07-2016

DOI: 10.1080/03721426.2016.1216735

Linkage Projects - Grant ID: LP110100066

Start Date: 11-2011

End Date: 12-2014

Amount: $132,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0883495

Start Date: 09-2008

End Date: 02-2012

Amount: $215,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0450472

Start Date: 2004

End Date: 06-2007

Amount: $225,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0562240

Start Date: 08-2005

End Date: 02-2009

Amount: $105,444.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0344618

Start Date: 2003

End Date: 12-2005

Amount: $126,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP110200105

Start Date: 12-2011

End Date: 12-2015

Amount: $296,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP1094894

Start Date: 2010

End Date: 12-2012

Amount: $375,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0877384

Start Date: 07-2008

End Date: 12-2011

Amount: $240,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP130100145

Start Date: 2013

End Date: 12-2016

Amount: $535,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0664408

Start Date: 02-2006

End Date: 12-2009

Amount: $220,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0776604

Start Date: 07-2007

End Date: 12-2012

Amount: $431,052.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE130100065

Start Date: 2013

End Date: 12-2014

Amount: $370,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP110103852

Start Date: 2011

End Date: 12-2014

Amount: $455,000.00

Funder: Australian Research Council