ORCID Profile
0000-0001-9460-8743
Current Organisations
University of New South Wales
,
Australian National University
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Life Histories | Ecology | Behavioural Ecology | Animal Behaviour | Evolutionary biology | Population ecology | Evolutionary ecology |
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Biological Sciences | Sparseland, Permanent Grassland and Arid Zone Flora, Fauna and Biodiversity | Climate and Climate Change not elsewhere classified |
Related Links
Publications
Learning outdoors: Male lizards show flexible spatial learning under semi-natural conditions
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.
VLEs, social stories and children with autism: A prototype implementation and evaluation
Publisher: Springer Science and Business Media LLC
Date: 26-05-2015
Plasticity leaves a phenotypic signature during local adaptation
Publisher: Oxford University Press (OUP)
Date: 08-2020
DOI: 10.1002/EVL3.185
Abstract: Phenotypic responses to a novel or extreme environment are initially plastic, only later to be followed by genetic change. Whether or not environmentally induced phenotypes are sufficiently recurrent and fit to leave a signature in adaptive evolution is debated. Here, we analyze multivariate data from 34 plant reciprocal transplant studies to test: (1) if plasticity is an adaptive source of developmental bias that makes locally adapted populations resemble the environmentally induced phenotypes of ancestors and (2) if plasticity, standing phenotypic variation and genetic ergence align during local adaptation. Phenotypic variation increased marginally in foreign environments but, as predicted, the direction of ancestral plasticity was generally well aligned with the phenotypic difference between locally adapted populations, making plasticity appear to "take the lead" in adaptive evolution. Plastic responses were sometimes more extreme than the phenotypes of locally adapted plants, which can give the impression that plasticity and evolutionary adaptation oppose each other however, environmentally induced and locally adapted phenotypes were rarely misaligned. Adaptive fine-tuning of phenotypes—genetic accommodation—did not fall along the main axis of standing phenotypic variation or the direction of plasticity, and local adaptation did not consistently modify the direction or magnitude of plasticity. These results suggest that plasticity is a persistent source of developmental bias that shapes how plant populations adapt to environmental change, even when plasticity does not constrain how populations respond to selection.
Patterns of developmental plasticity in response to incubation temperature in reptiles.
Publisher: Wiley
Date: 04-2018
DOI: 10.1002/JEZ.2181
Abstract: Early life environments shape phenotypic development in important ways that can lead to long-lasting effects on phenotype and fitness. In reptiles, one aspect of the early environment that impacts development is temperature (termed 'thermal developmental plasticity'). Indeed, the thermal environment during incubation is known to influence morphological, physiological, and behavioral traits, some of which have important consequences for many ecological and evolutionary processes. Despite this, few studies have attempted to synthesize and collate data from this expansive and important body of research. Here, we systematically review research into thermal developmental plasticity across reptiles, structured around the key papers and findings that have shaped the field over the past 50 years. From these papers, we introduce a large database (the 'Reptile Development Database') consisting of 9,773 trait means across 300 studies examining thermal developmental plasticity. This dataset encompasses data on a range of phenotypes, including morphological, physiological, behavioral, and performance traits along with growth rate, incubation duration, sex ratio, and survival (e.g., hatching success) across all major reptile clades. Finally, from our literature synthesis and data exploration, we identify key research themes associated with thermal developmental plasticity, important gaps in empirical research, and demonstrate how future progress can be made through targeted empirical, meta-analytic, and comparative work.
Dietary restriction increases variability in longevity
Publisher: The Royal Society
Date: 03-2017
Abstract: Nutritional environments, particularly those experienced during early life, are hypothesized to affect longevity. A recent cross-taxa meta-analysis found that, depending upon circumstance, average longevity may be increased or decreased by early-life dietary restriction. Unstudied are the effects of diet during development on among-in idual variance in longevity. Here, we address this issue using emerging methods for meta-analysis of variance. We found that, in general, standard deviation (s.d.) in longevity is around 8% higher under early-life dietary restriction than a standard diet. The effects became especially profound when dietary insults were experienced prenatally (s.d. increased by 29%) and/or extended into adulthood (s.d. increased by 36.6%). Early-life dietary restriction may generate variance in longevity as a result of increased variance in resource acquisition or allocation, but the mechanisms underlying these largely overlooked patterns clearly warrant elucidation.
Age-dependent social learning in a lizard
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.
Testing domain general learning in an Australian lizard
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.
Reproducible, flexible and high‐throughput data extraction from primary literature: The metaDigitise r package
Publisher: Wiley
Date: 26-11-2019
Meta-analytic approaches and effect sizes to account for ‘nuisance heterogeneity’ in comparative physiology
Publisher: The Company of Biologists
Date: 08-03-2022
DOI: 10.1242/JEB.243225
Abstract: Meta-analysis is a powerful tool used to generate quantitatively informed answers to pressing global challenges. By distilling data from broad sets of research designs and study systems into standardised effect sizes, meta-analyses provide physiologists with opportunities to estimate overall effect sizes and understand the drivers of effect variability. Despite this ambition, research designs in the field of comparative physiology can appear, at the outset, as being vastly different to each other because of ‘nuisance heterogeneity’ (e.g. different temperatures or treatment dosages used across studies). Methodological differences across studies have led many to believe that meta-analysis is an exercise in comparing ‘apples with oranges’. Here, we dispel this myth by showing how standardised effect sizes can be used in conjunction with multilevel meta-regression models to both account for the factors driving differences across studies and make them more comparable. We assess the prevalence of nuisance heterogeneity in the comparative physiology literature – showing it is common and often not accounted for in analyses. We then formalise effect size measures (e.g. the temperature coefficient, Q10) that provide comparative physiologists with a means to remove nuisance heterogeneity without the need to resort to more complex statistical models that may be harder to interpret. We also describe more general approaches that can be applied to a variety of different contexts to derive new effect sizes and s ling variances, opening up new possibilities for quantitative synthesis. By using effect sizes that account for components of effect heterogeneity, in combination with existing meta-analytic models, comparative physiologists can explore exciting new questions while making results from large-scale data sets more accessible, comparable and widely interpretable.
Sex- and performance-based escape behaviour in an Asian agamid lizard, Phrynocephalus vlangalii
Publisher: Springer Science and Business Media LLC
Date: 02-10-2014
Maternal and additive genetic effects contribute to variation in offspring traits in a lizard
Publisher: Oxford University Press (OUP)
Date: 15-03-2014
Publication bias impacts on effect size, statistical power, and magnitude (Type M) and sign (Type S) errors in ecology and evolutionary biology
Publisher: Springer Science and Business Media LLC
Date: 03-04-2023
DOI: 10.1186/S12915-022-01485-Y
Abstract: Collaborative efforts to directly replicate empirical studies in the medical and social sciences have revealed alarmingly low rates of replicability, a phenomenon dubbed the ‘replication crisis’. Poor replicability has spurred cultural changes targeted at improving reliability in these disciplines. Given the absence of equivalent replication projects in ecology and evolutionary biology, two inter-related indicators offer the opportunity to retrospectively assess replicability: publication bias and statistical power. This registered report assesses the prevalence and severity of small-study (i.e., smaller studies reporting larger effect sizes) and decline effects (i.e., effect sizes decreasing over time) across ecology and evolutionary biology using 87 meta-analyses comprising 4,250 primary studies and 17,638 effect sizes. Further, we estimate how publication bias might distort the estimation of effect sizes, statistical power, and errors in magnitude (Type M or exaggeration ratio) and sign (Type S). We show strong evidence for the pervasiveness of both small-study and decline effects in ecology and evolution. There was widespread prevalence of publication bias that resulted in meta-analytic means being over-estimated by (at least) 0.12 standard deviations. The prevalence of publication bias distorted confidence in meta-analytic results, with 66% of initially statistically significant meta-analytic means becoming non-significant after correcting for publication bias. Ecological and evolutionary studies consistently had low statistical power (15%) with a 4-fold exaggeration of effects on average (Type M error rates = 4.4). Notably, publication bias reduced power from 23% to 15% and increased type M error rates from 2.7 to 4.4 because it creates a non-random s le of effect size evidence. The sign errors of effect sizes (Type S error) increased from 5% to 8% because of publication bias. Our research provides clear evidence that many published ecological and evolutionary findings are inflated. Our results highlight the importance of designing high-power empirical studies (e.g., via collaborative team science), promoting and encouraging replication studies, testing and correcting for publication bias in meta-analyses, and adopting open and transparent research practices, such as (pre)registration, data- and code-sharing, and transparent reporting.
Unifying individual differences in personality, predictability and plasticity: A practical guide
Publisher: Wiley
Date: 20-11-2022
Abstract: Organisms use labile traits to respond to different conditions over short time‐scales. When a population experiences the same conditions, we might expect all in iduals to adjust their trait expression to the same, optimal, value, thereby minimising phenotypic variation. Instead, variation abounds. In iduals substantially differ not only from each other, but also from their former selves, with the expression of labile traits varying both predictably and unpredictably over time. A powerful tool for studying the evolution of phenotypic variation in labile traits is the mixed model. Here, we review how mixed models are used to quantify in idual differences in both means and variability, and their between‐in idual correlations. In iduals can differ in their average phenotypes (e.g. behavioural personalities), their variability (known as ‘predictability’ or intra‐in idual variability), and their plastic response to different contexts. We provide detailed descriptions and resources for simultaneously modelling in idual differences in averages, plasticity and predictability. Empiricists can use these methods to quantify how traits covary across in iduals and test theoretical ideas about phenotypic integration. These methods can be extended to incorporate plastic changes in predictability (termed ‘stochastic malleability’). Overall, we showcase the unfulfilled potential of existing statistical tools to test more holistic and nuanced questions about the evolution, function, and maintenance of phenotypic variation, for any trait that is repeatedly expressed.
Spatial and social organization in a burrow-dwelling lizard (Phrynocephalus vlangalii) from China
Publisher: Public Library of Science (PLoS)
Date: 23-07-2012
Timing of maternal exposure to toxic cyanobacteria and offspring fitness in Daphnia magna : Implications for the evolution of anticipatory maternal effects
Publisher: Wiley
Date: 20-11-2018
DOI: 10.1002/ECE3.4700
Species delineation using Bayesian model-based assignment tests: A case study using Chinese toad-headed agamas (genus Phrynocephalus)
Publisher: Springer Science and Business Media LLC
Date: 25-06-2010
Abstract: Species are fundamental units in biology, yet much debate exists surrounding how we should delineate species in nature. Species discovery now requires the use of separate, corroborating datasets to quantify independently evolving lineages and test species criteria. However, the complexity of the speciation process has ushered in a need to infuse studies with new tools capable of aiding in species delineation. We suggest that model-based assignment tests are one such tool. This method circumvents constraints with traditional population genetic analyses and provides a novel means of describing cryptic and complex ersity in natural systems. Using toad-headed agamas of the Phrynocephalus vlangalii complex as a case study, we apply model-based assignment tests to microsatellite DNA data to test whether P. putjatia , a controversial species that closely resembles P. vlangalii morphologically, represents a valid species. Mitochondrial DNA and geographic data are also included to corroborate the assignment test results. Assignment tests revealed two distinct nuclear DNA clusters with 95% (230/243) of the in iduals being assigned to one of the clusters with 90% probability. The nuclear genomes of the two clusters remained distinct in sympatry, particularly at three syntopic sites, suggesting the existence of reproductive isolation between the identified clusters. In addition, a mitochondrial ND2 gene tree revealed two deeply erged clades, which were largely congruent with the two nuclear DNA clusters, with a few exceptions. Historical mitochondrial introgression events between the two groups might explain the disagreement between the mitochondrial and nuclear DNA data. The nuclear DNA clusters and mitochondrial clades corresponded nicely to the hypothesized distributions of P. vlangalii and P. putjatia . These results demonstrate that assignment tests based on microsatellite DNA data can be powerful tools for distinguishing closely related species and support the validity of P. putjatia . Assignment tests have the potential to play a significant role in elucidating bio ersity in the era of DNA data. Nonetheless, important limitations do exist and multiple independent datasets should be used to corroborate results from assignment programs.
An assessment of statistical methods for nonindependent data in ecological meta‐analyses: Comment
Publisher: Wiley
Date: 20-10-2021
DOI: 10.1002/ECY.3490
Sex in unisexual salamanders: Discovery of a new sperm donor with ancient affinities
Publisher: Springer Science and Business Media LLC
Date: 29-07-2009
DOI: 10.1038/HDY.2009.83
Abstract: Although bisexual reproduction has considerable evolutionary benefits, several all-female vertebrates exist. Unisexual salamanders in the genus Ambystoma are common around the Great Lakes region in eastern North America. They originated from a hybridization event that involved a female that shared a common ancestor with Ambystoma barbouri 2.4 to 3.9 million years ago but, unexpectedly, A. barbouri nuclear genomes were unknown in unisexuals. Unisexual salamanders steal sperm from donors of normally bisexual species, so their reproductive mode is described as kleptogenesis. Most known unisexuals are polyploid and they all possess at least one A. laterale genome. One or more other genomes are taken from sperm donors that may include A. jeffersonianum, A. laterale, A. texanum and A. tigrinum. We examined unisexual adults and larvae in a southern Ohio pond where unisexual in iduals coexist with male A. barbouri. This population provided an opportunity to test hypotheses pertaining to the role of A. barbouri in the evolution of the disparate cytoplasmic and nuclear genomes in unisexual salamanders. Microsatellite DNA loci, mitochondrial DNA sequences and genomic in situ hybridization were used to identify the genomic constitution of in iduals. A. barbouri was found to be an acceptable sperm donor for unisexuals but only contributed genomes in ploidy-elevated in iduals. In the absence of A. jeffersonianum, this Ohio population is likely experiencing a recent switch in sperm donors from A. jeffersonianum to A. barbouri and demonstrates the evolutionary flexibility and dynamics of kleptogenesis.
Sex and boldness explain individual differences in spatial learning in a lizard
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.
The orchard plot: Cultivating a forest plot for use in ecology, evolution, and beyond
Publisher: Wiley
Date: 11-06-2020
DOI: 10.1002/JRSM.1424
Sex, androgens, and whole-organism performance in an Australian lizard
Publisher: Oxford University Press (OUP)
Date: 13-03-2014
DOI: 10.1111/BIJ.12252
Transgenerational effects of obesogenic diets in rodents: A meta‐analysis
Publisher: Wiley
Date: 30-09-2022
DOI: 10.1111/OBR.13342
Abstract: Obesity is a major health condition that affects millions worldwide. There is an increased interest in understanding the adverse outcomes associated with obesogenic diets. A multitude of studies have investigated the transgenerational impacts of maternal and parental obesogenic diets on subsequent generations of offspring, but results have largely been mixed. We conducted a systematic review and meta‐analysis on rodent studies to elucidate how obesogenic diets impact the mean and variance of grand‐offspring traits. Our study focused on transgenerational effects (i.e., F2 and F3 generations) in one‐off and multigenerational exposure studies. From 33 included articles, we obtained 407 effect sizes representing pairwise comparisons of control and treatment grand‐offspring groups pertaining to measures of body weight, adiposity, glucose, insulin, leptin, and triglycerides. We found evidence that male and female grand‐offspring descended from grandparents exposed to an obesogenic diet displayed phenotypes consistent with metabolic syndrome, especially in cases where the obesogenic diet was continued across generations. Further, we found stronger evidence for the effects of grand‐maternal than grand‐paternal exposure on grand‐offspring traits. A high‐fat diet in one‐off exposure studies did not seem to impact phenotypic variation, whereas in multigenerational exposure studies it reduced variation in several traits.
A robust and readily implementable method for the meta‐analysis of response ratios with and without missing standard deviations
Publisher: Wiley
Date: 26-12-2023
DOI: 10.1111/ELE.14144
Abstract: The log response ratio, lnRR, is the most frequently used effect size statistic for meta‐analysis in ecology. However, often missing standard deviations (SDs) prevent estimation of the s ling variance of lnRR. We propose new methods to deal with missing SDs via a weighted average coefficient of variation (CV) estimated from studies in the dataset that do report SDs. Across a suite of simulated conditions, we find that using the average CV to estimate s ling variances for all observations, regardless of missingness, performs with minimal bias. Surprisingly, even with missing SDs, this simple method outperforms the conventional approach (basing each effect size on its in idual study‐specific CV) with complete data. This is because the conventional method ultimately yields less precise estimates of the s ling variances than using the pooled CV from multiple studies. Our approach is broadly applicable and can be implemented in all meta‐analyses of lnRR, regardless of ‘missingness’.
Learning in non‐avian reptiles 40 years on: advances and promising new directions
Publisher: Wiley
Date: 19-10-2021
DOI: 10.1111/BRV.12658
Impact of developmental temperatures on thermal plasticity and repeatability of metabolic rate
Publisher: Springer Science and Business Media LLC
Date: 03-2022
DOI: 10.1007/S10682-022-10160-1
Abstract: Phenotypic plasticity is an important mechanism that allows populations to adjust to changing environments. Early life experiences can have lasting impacts on how in iduals respond to environmental variation later in life (i.e., in idual reaction norms), altering the capacity for populations to respond to selection. Here, we incubated lizard embryos ( L ropholis delicata ) at two fluctuating developmental temperatures (cold = 23 ºC + / − 3 ºC, hot = 29 ºC + / − 3 ºC, n cold = 26, n hot = 25) to understand how it affected metabolic plasticity to temperature later in life. We repeatedly measured in idual reaction norms across six temperatures 10 times over ~ 3.5 months (n obs = 3,818) to estimate the repeatability of average metabolic rate (intercept) and thermal plasticity (slope). The intercept and the slope of the population-level reaction norm was not affected by developmental temperature. Repeatability of average metabolic rate was, on average, 10% lower in hot incubated lizards but stable across all temperatures. The slope of the thermal reaction norm was overall moderately repeatable ( R = 0.44, 95% CI = 0.035 – 0.93) suggesting that in idual metabolic rate changed consistently with short-term changes in temperature, although credible intervals were quite broad. Importantly, reaction norm repeatability did not depend on early developmental temperature. Identifying factors affecting among-in idual variation in thermal plasticity will be increasingly more important for terrestrial ectotherms living in changing climate. Our work implies that thermal metabolic plasticity is robust to early developmental temperatures and has the capacity to evolve, despite there being less consistent variation in metabolic rate under hot environments.
Sexual dimorphism in conspicuousness and ornamentation in the enigmatic leaf-nosed lizard Ceratophora tennentii from Sri Lanka
Publisher: Oxford University Press (OUP)
Date: 14-07-2015
DOI: 10.1111/BIJ.12610
A meta‐analysis of sex differences in animal personality: no evidence for the greater male variability hypothesis
Publisher: Wiley
Date: 14-12-2021
DOI: 10.1111/BRV.12818
Abstract: The notion that men are more variable than women has become embedded into scientific thinking. For mental traits like personality, greater male variability has been partly attributed to biology, underpinned by claims that there is generally greater variation among males than females in non‐human animals due to stronger sexual selection on males. However, evidence for greater male variability is limited to morphological traits, and there is little information regarding sex differences in personality‐like behaviours for non‐human animals. Here, we meta‐analysed sex differences in means and variances for over 2100 effects (204 studies) from 220 species (covering five broad taxonomic groups) across five personality traits: boldness, aggression, activity, sociality and exploration. We also tested if sexual size dimorphism, a proxy for sex‐specific sexual selection, explains variation in the magnitude of sex differences in personality. We found no significant differences in personality between the sexes. In addition, sexual size dimorphism did not explain variation in the magnitude of the observed sex differences in the mean or variance in personality for any taxonomic group. In sum, we find no evidence for widespread sex differences in variability in non‐human animal personality.
Spontaneous quantity discrimination in a family-living lizard
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.
Activity predicts male reproductive success in a polygynous lizard
Publisher: Public Library of Science (PLoS)
Date: 11-07-2012
An efficient new assay for measuring zebrafish anxiety: Tall tanks that better characterize between-individual differences
Publisher: Elsevier BV
Date: 05-2021
Maternal behavioural thermoregulation facilitated evolutionary transitions from egg laying to live birth
Publisher: Cold Spring Harbor Laboratory
Date: 08-02-2021
DOI: 10.1101/2021.02.07.430163
Abstract: Live birth is a key innovation that has evolved from egg laying ancestors over 100 times in reptiles. However, egg-laying lizards and snakes often possess preferred body temperatures that are lethal to developing embryos, which should select against egg retention. Here, we demonstrate that thermal mismatches between mothers and offspring are widespread across the squamate phylogeny. This mismatch is resolved by gravid females adjusting their body temperature towards the thermal optimum of embryos. Importantly, phylogenetic reconstructions suggest this thermoregulatory behaviour evolved in egg-laying species prior to the evolution of live birth. Maternal thermoregulatory behaviour therefore bypasses the constraints imposed by a slowly evolving thermal physiology and has likely been a key facilitator in the repeated transitions to live birth.
Sexual selection on performance traits in an Australian lizard with alternative reproductive tactics
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.
Dominance and social information use in a lizard
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.
Advice for improving the reproducibility of data extraction in meta‐analysis
Publisher: Wiley
Date: 11-08-2023
DOI: 10.1002/JRSM.1663
Abstract: Extracting data from studies is the norm in meta‐analyses, enabling researchers to generate effect sizes when raw data are otherwise not available. While there has been a general push for increased reproducibility in meta‐analysis, the transparency and reproducibility of the data extraction phase is still lagging behind. Unfortunately, there is little guidance of how to make this process more transparent and shareable. To address this, we provide several steps to help increase the reproducibility of data extraction in meta‐analysis. We also provide suggestions of R software that can further help with reproducible data policies: the shinyDigitise and juicr packages. Adopting the guiding principles listed here and using the appropriate software will provide a more transparent form of data extraction in meta‐analyses.
Intergenerational effects of overfeeding on aversive learning in zebrafish (Danio rerio)
Publisher: Wiley
Date: 10-2022
DOI: 10.1002/ECE3.9423
Abstract: The obesity epidemic is concerning as obesity appears to negatively impact cognition and behavior. Furthermore, some studies suggest that this negative effect could be carried across generations from both mothers and fathers although evidence is not consistent. Here, we attempt to address how obesogenic diets in the parental generation (F0) can impact offspring's cognition and anxiety intergenerationally (F1) in a zebrafish model. We compare both mean trait values and their variances. Using a multifactorial design, we created a total of four groups: F1T (treatment mothers × treatment fathers) F1M (treatment mothers × control fathers) F1P (treatment fathers × control mothers) and F1C (control mothers × control fathers, F1C) and subjected them to anxiety tank tests and aversive learning assays. When both parents were exposed, offspring (F1T) displayed the poorest aversive learning, while offspring that only had one parent exposed (F1P and F1M) learnt the aversive learning task the best. Zebrafish in all groups displayed no statistically significant differences in anxiety‐associated behaviors. Males and females also performed similarly in both anxiety and aversive learning assays. While all F1 groups had similar levels of fasting blood glucose, variance in glucose levels were reduced in F1P and F1T indicating the importance of investigating heteroskedasticity between groups. Furthermore, anxiety behaviors of these two groups appeared to be less repeatable. To our knowledge, this is the first study to test the intergenerational effects of an obesogenic diet on zebrafish cognition. Our multifactorial design as well as repeated tests also allowed us to disentangle maternal and paternal effects (as well as combined effects) and accurately detect subtle information such as between‐in idual variation.
orchaRd 2.0: An R package for visualising meta‐analyses with orchard plots
Publisher: Wiley
Date: 06-06-2023
Abstract: Although meta‐analysis has become an essential tool in ecology and evolution, reporting of meta‐analytic results can still be much improved. To aid this, we have introduced the orchard plot, which presents not only overall estimates and their confidence intervals, but also shows corresponding heterogeneity (as prediction intervals) and in idual effect sizes. Here, we have added significant enhancements by integrating many new functionalities into orchaRd 2.0 . This updated version allows the visualisation of heteroscedasticity (different variances across levels of a categorical moderator), marginal estimates (e.g. marginalising out effects other than the one visualised), conditional estimates (i.e. estimates of different groups conditioned upon specific values of a continuous variable) and visualisations of all types of interactions between two categorical/continuous moderators. orchaRd 2.0 has additional functions which calculate key statistics from multilevel meta‐analytic models such as I 2 and R 2 . Importantly, orchaRd 2.0 contributes to better reporting by complying with PRISMA‐EcoEvo (preferred reporting items for systematic reviews and meta‐analyses in ecology and evolution). Taken together, orchaRd 2.0 can improve the presentation of meta‐analytic results and facilitate the exploration of previously neglected patterns. In addition, as a part of a literature survey, we found that graphical packages are rarely cited (~3%). We plea that researchers credit developers and maintainers of graphical packages, for ex le, by citations in a figure legend, acknowledging the use of relevant packages.
Developmental environments do not affect thermal physiological traits in reptiles: an experimental test and meta-analysis
Publisher: The Royal Society
Date: 05-2023
Abstract: On a global scale, organisms face significant challenges due to climate change and anthropogenic disturbance. In many ectotherms, developmental and physiological processes are sensitive to changes in temperature and resources. Developmental plasticity in thermal physiology may provide adaptive advantages to environmental extremes if early environmental conditions are predictive of late-life environments. Here, we conducted a laboratory experiment to test how developmental temperature and maternal resource investment influence thermal physiological traits (critical thermal maximum: CT max and thermal preference: T pref ) in a common skink ( L ropholis delicata ). We then compared our experimental findings more broadly across reptiles (snakes, lizards and turtles) using meta-analysis. In both our experimental study and meta-analysis, we did not find evidence that developmental environments influence CT max or T pref . Furthermore, the effects of developmental environments on thermal physiology did not vary by age, taxon or climate zone (temperate/tropical). Overall, the magnitude of developmental plasticity on thermal physiology appears to be limited across reptile taxa suggesting that behavioural or evolutionary processes may be more important. However, there is a paucity of information across most reptile taxa, and a broader focus on thermal performance curves themselves will be critical in understanding the impacts of changing thermal conditions on reptiles in the future.
Nonindependence and sensitivity analyses in ecological and evolutionary meta-analyses
Publisher: Wiley
Date: 09-03-2017
DOI: 10.1111/MEC.14031
Abstract: Meta-analysis is an important tool for synthesizing research on a variety of topics in ecology and evolution, including molecular ecology, but can be susceptible to nonindependence. Nonindependence can affect two major interrelated components of a meta-analysis: (i) the calculation of effect size statistics and (ii) the estimation of overall meta-analytic estimates and their uncertainty. While some solutions to nonindependence exist at the statistical analysis stages, there is little advice on what to do when complex analyses are not possible, or when studies with nonindependent experimental designs exist in the data. Here we argue that exploring the effects of procedural decisions in a meta-analysis (e.g. inclusion of different quality data, choice of effect size) and statistical assumptions (e.g. assuming no phylogenetic covariance) using sensitivity analyses are extremely important in assessing the impact of nonindependence. Sensitivity analyses can provide greater confidence in results and highlight important limitations of empirical work (e.g. impact of study design on overall effects). Despite their importance, sensitivity analyses are seldom applied to problems of nonindependence. To encourage better practice for dealing with nonindependence in meta-analytic studies, we present accessible ex les demonstrating the impact that ignoring nonindependence can have on meta-analytic estimates. We also provide pragmatic solutions for dealing with nonindependent study designs, and for analysing dependent effect sizes. Additionally, we offer reporting guidelines that will facilitate disclosure of the sources of nonindependence in meta-analyses, leading to greater transparency and more robust conclusions.
Baiting in conservation and pest management: A systematic review of its global applications in a changing world
Publisher: Elsevier BV
Date: 08-2023
Sex and Power: sexual dimorphism in trait variability and its eco-evolutionary and statistical implications
Publisher: Cold Spring Harbor Laboratory
Date: 26-05-2020
DOI: 10.1101/2020.05.23.106146
Abstract: Biomedical and clinical sciences are experiencing a renewed interest in the fact that males and females differ in many anatomic, physiological, and behavioral traits. Sex differences in trait variability, however, are yet to receive similar recognition. In medical science, mammalian females are assumed to have higher trait variability due to estrous cycles (the ‘estrus-mediated variability hypothesis’) historically in biomedical research, females have been excluded for this reason. Contrastingly, evolutionary theory and associated data support the ‘greater male variability hypothesis’. Here, we test these competing hypotheses in 218 traits measured in ,900 mice, using meta-analysis methods. Neither hypothesis could universally explain patterns in trait variability. Sex-bias in variability was trait-dependent. While greater male variability was found in morphological traits, females were much more variable in immunological traits. Sex-specific variability has eco-evolutionary ramifications including sex-dependent responses to climate change, as well as statistical implications including power analysis considering sex difference in variance.
The jury is still out regarding the generality of adaptive ‘transgenerational’ effects
Publisher: Wiley
Date: 26-08-2020
DOI: 10.1111/ELE.13479
Behavioral and morphological traits interact to promote the evolution of alternative reproductive tactics in a lizard
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.
Hybridization between two gartersnake species (Thamnophis) of conservation concern: A threat or an important natural interaction?
Publisher: Springer Science and Business Media LLC
Date: 15-01-2012
Individual variation in thermal plasticity and its impact on mass‐scaling
Publisher: Wiley
Date: 29-04-2021
DOI: 10.1111/OIK.08122
Abstract: Physiological processes vary widely across in iduals and can influence how in iduals respond to environmental change. Repeatability in how metabolic rate changes across temperatures (i.e. metabolic thermal plasticity) can influence mass‐scaling exponents in different thermal environments. Moreover, repeatable plastic responses are necessary for reaction norms to respond to selective forces which is important for populations living in fluctuating environments. Nonetheless, only a small number of studies have explicitly quantified repeatability in metabolic plasticity, and fewer have explored how it can impact mass‐scaling. We repeatedly measured standard metabolic rate of n = 42 delicate skinks L ropholis delicata at six temperatures over the course of four months ( N [observations] = 4952). Using hierarchical statistical techniques, we accounted for multi‐level variation and measurement error in our data in order to obtain more precise estimates of reaction norm repeatability and mass‐scaling exponents at different acute temperatures. Our results show that in idual differences in metabolic thermal plasticity were somewhat consistent over time (R slope = 0.25, 95% CI = 2.48 × 10 −8 – 0.67), however estimates were associated with a large degree of error. After accounting for measurement error, which decreased steadily with temperature, we show that among in idual variance remained consistent across all temperatures. Congruently, temperature specific repeatability of average metabolic rate was stable across temperatures. Cross‐temperature correlations were positive but were not uniform across the reaction norm. After taking into account multiple sources of variation, our estimates for mass‐scaling did not change with temperature and were in line with published values for snakes and lizards. This implies that repeatable plastic responses may promote thermal stability of scaling exponents. Our work contributes to understanding how energy expenditure scales with abiotic and biotic factors and the capacity for reaction norms to respond to selection.
Impact of fluctuating developmental temperatures on phenotypic traits in reptiles: a meta-analysis.
Publisher: The Company of Biologists
Date: 08-03-2022
DOI: 10.1242/JEB.243369
Abstract: During the vulnerable stages of early life, most ectothermic animals experience hourly and diel fluctuations in temperature as air temperatures change. While we know a great deal about how different constant temperatures impact the phenotypes of developing ectotherms, we know remarkably little about the impacts of temperature fluctuations on the development of ectotherms. In this study, we used a meta-analytic approach to compare the mean and variance of phenotypic outcomes from constant and fluctuating incubation temperatures across reptile species. We found that fluctuating temperatures provided a small benefit (higher hatching success and shorter incubation durations) at cool mean temperatures compared with constant temperatures, but had a negative effect at warm mean temperatures. In addition, more extreme temperature fluctuations led to greater reductions in embryonic survival compared with moderate temperature fluctuations. Within the limited data available from species with temperature-dependent sex determination, embryos had a higher chance of developing as female when developing in fluctuating temperatures compared with those developing in constant temperatures. With our meta-analytic approach, we identified average mean nest temperatures across all taxa where reptiles switch from receiving benefits to incurring costs when incubation temperatures fluctuate. More broadly, our study indicates that the impact of fluctuating developmental temperature on some phenotypes in ectothermic taxa are likely to be predictable via integration of developmental temperature profiles with thermal performance curves.
Sexual dimorphism in trait variability and its eco-evolutionary and statistical implications
Publisher: eLife Sciences Publications, Ltd
Date: 17-11-2020
DOI: 10.7554/ELIFE.63170
Abstract: Biomedical and clinical sciences are experiencing a renewed interest in the fact that males and females differ in many anatomic, physiological, and behavioural traits. Sex differences in trait variability, however, are yet to receive similar recognition. In medical science, mammalian females are assumed to have higher trait variability due to estrous cycles (the ‘estrus-mediated variability hypothesis’) historically in biomedical research, females have been excluded for this reason. Contrastingly, evolutionary theory and associated data support the ‘greater male variability hypothesis’. Here, we test these competing hypotheses in 218 traits measured in ,900 mice, using meta-analysis methods. Neither hypothesis could universally explain patterns in trait variability. Sex bias in variability was trait-dependent. While greater male variability was found in morphological traits, females were much more variable in immunological traits. Sex-specific variability has eco-evolutionary ramifications, including sex-dependent responses to climate change, as well as statistical implications including power analysis considering sex difference in variance.
Multiple mating in a lizard increases fecundity but provides no evidence for genetic benefits
Publisher: Oxford University Press (OUP)
Date: 09-05-2013
Preferred reporting items for systematic reviews and meta‐analyses in ecology and evolutionary biology: a PRISMA extension
Publisher: Wiley
Date: 07-05-2021
DOI: 10.1111/BRV.12721
Abstract: Since the early 1990s, ecologists and evolutionary biologists have aggregated primary research using meta‐analytic methods to understand ecological and evolutionary phenomena. Meta‐analyses can resolve long‐standing disputes, dispel spurious claims, and generate new research questions. At their worst, however, meta‐analysis publications are wolves in sheep's clothing: subjective with biased conclusions, hidden under coats of objective authority. Conclusions can be rendered unreliable by inappropriate statistical methods, problems with the methods used to select primary research, or problems within the primary research itself. Because of these risks, meta‐analyses are increasingly conducted as part of systematic reviews, which use structured, transparent, and reproducible methods to collate and summarise evidence. For readers to determine whether the conclusions from a systematic review or meta‐analysis should be trusted – and to be able to build upon the review – authors need to report what they did, why they did it, and what they found. Complete, transparent, and reproducible reporting is measured by ‘reporting quality’. To assess perceptions and standards of reporting quality of systematic reviews and meta‐analyses published in ecology and evolutionary biology, we surveyed 208 researchers with relevant experience (as authors, reviewers, or editors), and conducted detailed evaluations of 102 systematic review and meta‐analysis papers published between 2010 and 2019. Reporting quality was far below optimal and approximately normally distributed. Measured reporting quality was lower than what the community perceived, particularly for the systematic review methods required to measure trustworthiness. The minority of assessed papers that referenced a guideline (~16%) showed substantially higher reporting quality than average, and surveyed researchers showed interest in using a reporting guideline to improve reporting quality. The leading guideline for improving reporting quality of systematic reviews is the Preferred Reporting Items for Systematic reviews and Meta‐Analyses (PRISMA) statement. Here we unveil an extension of PRISMA to serve the meta‐analysis community in ecology and evolutionary biology: PRISMA‐EcoEvo (version 1.0). PRISMA‐EcoEvo is a checklist of 27 main items that, when applicable, should be reported in systematic review and meta‐analysis publications summarising primary research in ecology and evolutionary biology. In this explanation and elaboration document, we provide guidance for authors, reviewers, and editors, with explanations for each item on the checklist, including supplementary ex les from published papers. Authors can consult this PRISMA‐EcoEvo guideline both in the planning and writing stages of a systematic review and meta‐analysis, to increase reporting quality of submitted manuscripts. Reviewers and editors can use the checklist to assess reporting quality in the manuscripts they review. Overall, PRISMA‐EcoEvo is a resource for the ecology and evolutionary biology community to facilitate transparent and comprehensively reported systematic reviews and meta‐analyses.
Unisexual salamanders (genus Ambystoma) present a new reproductive mode for eukaryotes
Publisher: Canadian Science Publishing
Date: 02-2007
DOI: 10.1139/G06-152
Abstract: To persist, unisexual and asexual eukaryotes must have reproductive modes that circumvent normal bisexual reproduction. Parthenogenesis, gynogenesis, and hybridogenesis are the modes that have generally been ascribed to various unisexuals. Unisexual Ambystoma are abundant around the Great Lakes region of North America, and have variously been described as having all 3 reproductive modes. Diploid and polyploid unisexuals have nuclear genomes that combine the haploid genomes of 2 to 4 distinct sexual species, but the mtDNA is unlike any of those 4 species and is similar to another species, Ambystoma barbouri . To obtain better resolution of the reproductive mode used by unisexual Ambystoma and to explore the relationship of A. barbouri to the unisexuals, we sequenced the mitochondrial control and highly variable intergenic spacer region of 48 ambystomatids, which included 28 unisexuals, representatives of the 4 sexual species and A. barbouri. The unisexuals have similar sequences over most of their range, and form a close sister group to A. barbouri, with an estimated time of ergence of 2.4–3.9 million years ago. In iduals from the Lake Erie Islands (Kelleys, Pelee, North Bass) have a haplotype that demonstrates an isolation event. We examined highly variable microsatellite loci, and found that the genetic makeup of the unisexuals is highly variable and that unisexual in iduals share microsatellite alleles with sexual in iduals within populations. Although many progeny from the same female had the same genotype for 5 microsatellite DNA loci, there was no indication that any particular genome is consistently inherited in a clonal fashion in a population. The reproductive mode used by unisexual Ambystoma appears to be unique we suggest kleptogenesis as a new unisexual reproductive mode that is used by these salamanders.
Learning simple and compound stimuli in a social lizard (Egernia stokesii).
Publisher: American Psychological Association (APA)
Date: 05-2021
DOI: 10.1037/COM0000260
Author response: Sexual dimorphism in trait variability and its eco-evolutionary and statistical implications
Publisher: eLife Sciences Publications, Ltd
Date: 29-10-2020
The effects of an obesogenic diet on behavior and cognition in zebrafish (Danio rerio): Trait average, variability, repeatability, and behavioral syndromes
Publisher: Wiley
Date: 11-2022
DOI: 10.1002/ECE3.9511
Abstract: The obesity epidemic, largely driven by the accessibility of ultra‐processed high‐energy foods, is one of the most pressing public health challenges of the 21st century. Consequently, there is increasing concern about the impacts of diet‐induced obesity on behavior and cognition. While research on this matter continues, to date, no study has explicitly investigated the effect of obesogenic diet on variance and covariance (correlation) in behavioral traits. Here, we examined how an obesogenic versus control diet impacts means and (co‐)variances of traits associated with body condition, behavior, and cognition in a laboratory population of ~160 adult zebrafish ( Danio rerio ). Overall, an obesogenic diet increased variation in several zebrafish traits. Zebrafish on an obesogenic diet were significantly heavier and displayed higher body weight variability fasting blood glucose levels were similar between control and treatment zebrafish. During behavioral assays, zebrafish on the obesogenic diet displayed more exploratory behavior and were less reactive to video stimuli with conspecifics during a personality test, but these significant differences were sex‐specific. Zebrafish on an obesogenic diet also displayed repeatable responses in aversive learning tests whereas control zebrafish did not, suggesting an obesogenic diet resulted in more consistent, yet impaired, behavioral responses. Where behavioral syndromes existed (inter‐class correlations between personality traits), they did not differ between obesogenic and control zebrafish groups. By integrating a multifaceted, holistic approach that incorporates components of (co‐)variances, future studies will greatly benefit by quantifying neglected dimensions of obesogenic diets on behavioral changes.
Planned missing data designs and methods: Options for strengthening inference, increasing research efficiency and improving animal welfare in ecological and evolutionary research
Publisher: Wiley
Date: 22-07-2021
DOI: 10.1111/EVA.13273
Abstract: Ecological and evolutionary research questions are increasingly requiring the integration of research fields along with larger data sets to address fundamental local‐ and global‐scale problems. Unfortunately, these agendas are often in conflict with limited funding and a need to balance animal welfare concerns. Planned missing data design (PMDD), where data are randomly and deliberately missed during data collection, combined with missing data procedures, can be useful tools when working under greater research constraints. Here, we review how PMDD can be incorporated into existing experimental designs by discussing alternative design approaches and demonstrate with simulated data sets how missing data procedures work with incomplete data. PMDDs can provide researchers with a unique toolkit that can be applied during the experimental design stage. Planning and thinking about missing data early can (1) reduce research costs by allowing for the collection of less expensive measurement variables (2) provide opportunities to distinguish predictions from alternative hypotheses by allowing more measurement variables to be collected and (3) minimize distress caused by experimentation by reducing the reliance on invasive procedures or allowing data to be collected on fewer subjects (or less often on a given subject). PMDDs and missing data methods can even provide statistical benefits under certain situations by improving statistical power relative to a complete case design. The impacts of unplanned missing data, which can cause biases in parameter estimates and their uncertainty, can also be ameliorated using missing data procedures. PMDDs are still in their infancy. We discuss some of the difficulties in their implementation and provide tentative solutions. While PMDDs may not always be the best option, missing data procedures are becoming more sophisticated and more easily implemented and it is likely that PMDDs will be effective tools for a wide range of experimental designs, data types and problems in ecology and evolution.
Heightened among-individual variation in life history but not morphology is related to developmental temperature in reptiles.
Publisher: Wiley
Date: 11-10-2021
DOI: 10.1111/JEB.13938
Abstract: Increases in phenotypic variation under extreme (e.g. novel or stressful) environmental conditions are emerging as a crucial process through which evolutionary adaptation can occur. Lack of prior stabilizing selection, as well as potential instability of developmental processes in these environments, may lead to a release of phenotypic variation that can have important evolutionary consequences. Although such patterns have been shown in model study organisms, we know little about the generality of trait variance across environments for non-model organisms. Here, we test whether extreme developmental temperatures increase the phenotypic variation across erse reptile taxa. We find that the among-in idual variation in a key life-history trait (post-hatching growth) increases at extreme cold and hot temperatures. However, variations in two measures of hatchling morphology and in hatchling performance were not related to developmental temperature. Although extreme developmental temperatures may increase the variation in growth, our results suggest that plastic responses to stressful incubation conditions do not generally make more extreme phenotypes available to selection. We discuss the reasons for the general lack of increased variability at extreme incubation temperatures and the implications this has for local adaptation in hatchling morphology and physiology.
Precocial juvenile lizards show adult level learning and behavioural flexibility
Publisher: Elsevier BV
Date: 08-2019
Context-specific response inhibition and differential impact of a learning bias in a lizard
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.
Integrating Mitochondrial Aerobic Metabolism into Ecology and Evolution.
Publisher: Elsevier BV
Date: 04-2021
Developmental plasticity in thermal tolerance: Ontogenetic variation, persistence, and future directions.
Publisher: Wiley
Date: 25-08-2022
DOI: 10.1111/ELE.14083
Abstract: Understanding the factors affecting thermal tolerance is crucial for predicting the impact climate change will have on ectotherms. However, the role developmental plasticity plays in allowing populations to cope with thermal extremes is poorly understood. Here, we meta-analyse how thermal tolerance is initially and persistently impacted by early (embryonic and juvenile) thermal environments by using data from 150 experimental studies on 138 ectothermic species. Thermal tolerance only increased by 0.13°C per 1°C change in developmental temperature and substantial variation in plasticity (~36%) was the result of shared evolutionary history and species ecology. Aquatic ectotherms were more than three times as plastic as terrestrial ectotherms. Notably, embryos expressed weaker but more heterogenous plasticity than older life stages, with numerous responses appearing as non-adaptive. While developmental temperatures did not have persistent effects on thermal tolerance overall, persistent effects were vastly under-studied, and their direction and magnitude varied with ontogeny. Embryonic stages may represent a critical window of vulnerability to changing environments and we urge researchers to consider early life stages when assessing the climate vulnerability of ectotherms. Overall, our synthesis suggests that developmental changes in thermal tolerance rarely reach levels of perfect compensation and may provide limited benefit in changing environments.
Colour discrimination and associative learning in hatchling lizards incubated at ‘hot’ and ‘cold’ temperatures
Publisher: Springer Science and Business Media LLC
Date: 11-10-2014
Sex-dependent discrimination learning in lizards: A meta-analysis
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.
Early social environment influences the behaviour of a family-living lizard
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.
Beneficial intergenerational effects of exercise on brain and cognition
Publisher: Wiley
Date: 29-03-2021
DOI: 10.1111/BRV.12712
Abstract: Physical exercise not only helps to improve physical health but can also enhance brain development and cognition. Recent reports on parental (both maternal and paternal) effects raise the possibility that parental exercise may provide benefits to offspring through intergenerational inheritance. However, the general magnitude and consistency of parental exercise effects on offspring is still controversial. Additionally, empirical research has long overlooked an important aspect of exercise: its effects on variability in neurodevelopmental and cognitive traits. Here, we compiled data from 52 studies involving 4786 rodents (412 effect sizes) to quantify the intergenerational transmission of exercise effects on brain and cognition. Using a multilevel meta‐analytic approach, we found that, overall, parental exercise showed a tendency for increasing their offspring's brain structure by 12.7% (albeit statistically non‐significant) probably via significantly facilitating neurogenesis (16.5%). Such changes in neural anatomy go in hand with a significant 20.8% improvement in neurobehaviour (improved learning and memory, and reduced anxiety). Moreover, we found parental exercise significantly reduces inter‐in idual differences (i.e. reduced variance in the treatment group) in progeny's neurobehaviour by 10.2% (coefficient of variation ratio, lnCVR), suggesting the existence of an in idual by intervention interaction. The positive effects of exercise are modulated by several covariates (i.e. moderators), such as the exercised parent's sex, offspring's sex, and age, mode of exercise, and exercise timing. In particular, parental forced exercise is more efficient than voluntary exercise at significantly improving offspring neurobehaviour (26.0%) and reducing its variability (14.2%). We observed larger effects when parental exercise started before pregnancy. However, exercising only during pregnancy also had positive effects. Mechanistically, exercise significantly upregulated brain‐derived neurotrophic factor (BDNF) by 28.9%, vascular endothelial growth factor (VEGF) by 35.8%, and significantly decreased hippoc al DNA methylation by 3.5%, suggesting that brain growth factor cascades and epigenetic modifications can moderate the transmission of parental exercise effects. Collectively, by coupling mean with variance effects, our analyses draw a more integrated picture of the benefits that parental exercise has on offspring: not only does it improve offspring brain development and cognitive performance, but it also reduces inter‐in idual differences in cognition‐related traits. We advocate that meta‐analysis of variation together with the mean of a trait provides novel insights for old controversies as well as emerging new questions, opening up a new era for generating variance‐based hypotheses.
Methods for testing publication bias in ecological and evolutionary meta‐analyses
Publisher: Wiley
Date: 10-11-2022
Abstract: Publication bias threatens the validity of quantitative evidence from meta‐analyses as it results in some findings being overrepresented in meta‐analytic datasets because they are published more frequently or sooner (e.g. ‘positive’ results). Unfortunately, methods to test for the presence of publication bias, or assess its impact on meta‐analytic results, are unsuitable for datasets with high heterogeneity and non‐independence, as is common in ecology and evolutionary biology. We first review both classic and emerging publication bias tests (e.g. funnel plots, Egger's regression, cumulative meta‐analysis, fail‐safe N , trim‐and‐fill tests, p ‐curve and selection models), showing that some tests cannot handle heterogeneity, and, more importantly, none of the methods can deal with non‐independence. For each method, we estimate current usage in ecology and evolutionary biology, based on a representative s le of 102 meta‐analyses published in the last 10 years. Then, we propose a new method using multilevel meta‐regression, which can model both heterogeneity and non‐independence, by extending existing regression‐based methods (i.e. Egger's regression). We describe how our multilevel meta‐regression can test not only publication bias, but also time‐lag bias, and how it can be supplemented by residual funnel plots. Overall, we provide ecologists and evolutionary biologists with practical recommendations on which methods are appropriate to employ given independent and non‐independent effect sizes. No method is ideal, and more simulation studies are required to understand how Type 1 and Type 2 error rates are impacted by complex data structures. Still, the limitations of these methods do not justify ignoring publication bias in ecological and evolutionary meta‐analyses.
Population genetic structure of the endangered Butler's Gartersnake (Thamnophis butleri): Does the Short-headed Gartersnake (Thamnophis brachystoma) exist in Canada?
Publisher: Canadian Science Publishing
Date: 11-2013
Abstract: Understanding population genetic structure is fundamental to conservation of endangered species. It is particularly important when working with species that are morphologically conserved because strong genetic isions could represent cryptic species. Butler’s Gartersnake (Thamnophis butleri (Cope, 1889)) is an endangered species in Canada, having a fragmented distribution and being restricted to southwestern Ontario. Furthermore, it is difficult to distinguish morphologically from a closely related species, the Short-headed Gartersnake (Thamnophis brachystoma (Cope, 1892)). We use mitochondrial DNA (mtDNA) and seven microsatellite DNA loci to evaluate the genetic structure of Canadian T. butleri populations and to test for the presence of T. brachystoma in one of these populations. All in iduals had the same mtDNA haplotype, and there was no evidence of multiple, syntopic genetic clusters, thereby rejecting the hypothesis that T. butleri and T. brachystoma co-exist in Canada. Two different model-based assignment tests using microsatellite DNA data suggest that there are four to five genetically distinct clusters of T. butleri (F ST from 0.12 to 0.20). We provide the first population genetic study of T. butleri in Canada and refute the presence of T. brachystoma. Our results may provide guidance on recovery strategies for this species and identify areas to target fine-scale genetic analyses.
Diving in hot water: a meta-analytic review of how diving vertebrate ectotherms will fare in a warmer world
Publisher: The Company of Biologists
Date: 15-02-2021
DOI: 10.1242/JEB.228213
Abstract: Diving ectothermic vertebrates are an important component of many aquatic ecosystems, but the threat of climate warming is particularly salient to this group. Dive durations typically decrease as water temperatures rise yet, we lack an understanding of whether this trend is apparent in all ing ectotherms and how this group will fare under climate warming. We compiled data from 27 studies on 20 ectothermic vertebrate species to quantify the effect of temperature on e durations. Using meta-analytic approaches, we show that, on average, e durations decreased by 11% with every 1°C increase in water temperature. Larger increases in temperature (e.g. +3°C versus +8–9°C) exerted stronger effects on e durations. Although species that respire bimodally are projected to be more resilient to the effects of temperature on e durations than purely aerial breathers, we found no significant difference between these groups. Body mass had a weak impact on mean e durations, with smaller ers being impacted by temperature more strongly. Few studies have examined thermal phenotypic plasticity (N=4) in ing ectotherms, and all report limited plasticity. Average water temperatures in marine and freshwater habitats are projected to increase between 1.5 and 4°C in the next century, and our data suggest that this magnitude of warming could translate to substantial decreases in e durations, by approximately 16–44%. Together, these data shed light on an overlooked threat to ing ectothermic vertebrates and suggest that time available for underwater activities, such as predator avoidance and foraging, may be shortened under future warming.
Plastic responses to novel environments are biased towards phenotype dimensions with high additive genetic variation
Publisher: Proceedings of the National Academy of Sciences
Date: 19-06-2019
Abstract: Environmentally induced phenotypes have been proposed to initiate and bias adaptive evolutionary change toward particular directions. The potential for this to happen depends in part on how well plastic responses are aligned with the additive genetic variance and covariance in traits. Using meta-analysis, we demonstrate that plastic responses to novel environments tend to occur along phenotype dimensions that harbor substantial amounts of additive genetic variation. This suggests that selection for or against environmentally induced phenotypes typically will be effective. One interpretation of the alignment between the direction of plasticity and the main axis of additive genetic variation is that developmental systems tend to respond to environmental novelty as they do to genetic mutation. This makes it challenging to distinguish if the direction of evolution is biased by plasticity or genetic “constraint.” Our results therefore highlight a need for new theoretical and empirical approaches to address the role of plasticity in evolution.
Reproducible research in the study of biological coloration
Publisher: Elsevier BV
Date: 08-2015
Isolation rearing does not constrain social plasticity in a family-living lizard
Publisher: Oxford University Press (OUP)
Date: 07-03-2018
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