Tiliqua Rugosa Research Articles

Serpentoviruses in Free-Ranging Shingleback Skinks (Tiliqua rugosa) in Western Australia and South Australia, Australia.

Serpentoviruses are strongly associated with upper respiratory tract disease in captive and free-ranging bluetongued skinks (Tiliqua spp.). In Australia, bluetongue serpentoviruses were first reported in shingleback skinks (Tiliqua rugosa) with upper respiratory tract disease that presented to wildlife rehabilitation facilities in Perth, Western Australia. Since then, serpentoviruses have been detected commonly in captive bluetongued skinks from most areas of Australia, yet knowledge about the prevalence and distribution of these viruses in free-ranging bluetongued skinks, and other skink species, remains limited. Oral swabs were collected from 162 shingleback skinks from four areas in Western Australia and neighboring South Australia to screen for bluetongue serpentoviruses by PCR. The proportions of PCR positives were 0% (0/4) for Rottnest Island (a small island west of Perth, Western Australia), 3% (1/32) for the Shire of Kent (∼5,600 km2 in the southwest of Western Australia), 1% (1/91) from an approximately 250,000 km2 area across South Australia and Western Australia, and 0% (0/35) from Mount Mary (∼150 km2 in the mid north of South Australia). Neither of the two PCR-positive shingleback skinks had overt signs of upper respiratory tract disease. These results are consistent with serpentoviruses occurring at a relatively low crude prevalence of 1.4% (95% confidence interval, 0.2-4.9%) across these areas, although the potential bias from sampling active and apparently healthy individuals may mean that this estimate is lower than the true prevalence. This contrasts with the high proportion of PCR positives reported in captive individuals. In the absence of experimental or observational data on viral clearance and recovery, Tiliqua spp. skinks that are intended for release into the wild should be housed with strict biosecurity to prevent interactions with captive individuals and screened to ensure that they are not PCR positive before release.

Resource manipulation reveals interactive phenotype-dependent foraging in free-ranging lizards.

Recent evidence suggests that individuals differ in foraging tactics and this variation is often linked to an individual's behavioural type (BT). Yet, while foraging typically comprises a series of search and handling steps, empirical investigations have rarely considered BT-dependent effects across multiple stages of the foraging process, particularly in natural settings. In our long-term sleepy lizard (Tiliqua rugosa) study system, individuals exhibit behavioural consistency in boldness (measured as an individual's willingness to approach a novel food item in the presence of a threat) and aggressiveness (measured as an individual's response to an 'attack' by a conspecific dummy). These BTs are only weakly correlated and have previously been shown to have interactive effects on lizard space use and movement, suggesting that they could also affect lizard foraging performance, particularly in their search behaviour for food. To investigate how lizards' BTs affect their foraging process in the wild, we supplemented food in 123 patches across a 120-ha study site with three food abundance treatments (high, low and no-food controls). Patches were replenished twice a week over the species' entire spring activity season and feeding behaviours were quantified with camera traps at these patches. We tracked lizards using GPS to determine their home range (HR) size and repeatedly assayed their aggressiveness and boldness in designated assays. We hypothesised that bolder lizards would be more efficient foragers while aggressive ones would be less attentive to the quality of foraging patches. We found an interactive BT effect on overall foraging performance. Individuals that were both bold and aggressive ate the highest number of food items from the foraging array. Further dissection of the foraging process showed that aggressive lizards in general ate the fewest food items in part because they visited foraging patches less regularly, and because they discriminated less between high and low-quality patches when revisiting them. Bolder lizards, in contrast, ate more tomatoes because they visited foraging patches more regularly, and ate a higher proportion of the available tomatoes at patches during visits. Our study demonstrates that BTs can interact to affect different search and handling components of the foraging process, leading to within-population variation in foraging success. Given that individual differences in foraging and movement will influence social and ecological interactions, our results highlight the potential role of BT's in shaping individual fitness strategies and population dynamics.

The parasites of free-ranging terrestrial wildlife from Australia’s south-west

The conservation management of threatened wildlife increasingly relies upon translocations to augment populations. Translocations, however, pose various risks: from the host perspective these include the spread of parasitic disease, whereas from a broader biodiversity perspective translocation may lead to the loss of rare parasites and other dependent fauna. Although Disease Risk Analyses are recommended during translocation planning, knowledge regarding the parasites infecting threatened species or their pathogenicity is often lacking. Between March 2014 and June 2016, woylies (Bettongia penicillata) and sympatric marsupials were screened for the presence of endo- and ectoparasites, during two fauna translocations in south-western Australia. Here, we summarise the parasite taxa identified from B. penicillata, brush-tailed possums (Trichosurus vulpecula hypoleucus) and chuditch (Dasyurus geoffroii), including prevalence data for host, parasite taxon and site. Results from the opportunistic sampling of other species (Isoodon fusciventer, Phascogale tapoatafa wambenger, Tiliqua rugosa and Felis catus) are also presented. New host–parasite records including Hepatozoon spp. from T. v. hypoleucus, Trypanosoma noyesi from T. rugosa, Ixodes australiensis and Ixodes tasmani from D. geoffroii, and I. australiensis and Amblyomma sp. from a P. t. wambenger were identified. This study highlights the importance of monitoring sympatric species, particularly when compiling baseline data of parasite fauna present within translocation sites and enhances our knowledge of parasites infecting terrestrial wildlife within Australia’s south-west, a Global Biodiversity Hotspot.

A field experiment reveals reciprocal effects of host personality and parasitism in wild lizards

Abstract Host behavior and parasite infection reciprocally interact, but this dynamic is rarely studied experimentally in the field with multiple behaviors. We investigated the interplay between parasitism and host behavior via an in situ experimental tick infestation of a wild population of sleepy lizards, Tiliqua rugosa. Using Bayesian models, we assessed the relationship between experimental infestation and lizard aggression and boldness before and after infestation. First, we tested whether lizard aggression and boldness prior to infestation predicted the probability of tick attachment in the infestation experiment. Second, we evaluated whether experimental infestation affected subsequent lizard aggression and boldness. We found that aggression and boldness related interactively with infestation: for unaggressive lizards, higher boldness was associated with reduced experimental infestation success, but the opposite occurred for aggressive individuals. Second, increased tick infestation did not affect post-infestation aggression, but tended to increase boldness. Taken together, these results highlight the potential for feedbacks between parasites and multi-dimensional host behaviors.

Spontaneous quantity discrimination in the Australian sleepy lizard (Tiliqua rugosa)

Abstract Animals employ quantitative abilities to gauge crucial aspects of their environment, such as food or predator density in a given area or the number of eggs in a nest. These quantitative skills hold ecological implications and can impact an animal’s fitness. However, our comprehension of how these abilities intersect with environmental challenges remains limited. We tested for spontaneous quantity discrimination in the sleepy lizard (Tiliqua rugosa), a long-lived species known for forming life-long pair bonds in which pairs come together for the breeding season. We subjected lizards to a Y-maze experiment presenting both discrete (comparisons involving two vs. four, two vs. six, two vs. eight, four vs. six, four vs. eight, and six vs. eight pieces) and equivalent continuous combinations (single pieces differing in size) of pumpkin pieces. Our findings revealed that sleepy lizards exhibited spontaneous quantity discrimination, favoring the larger quantity in three discrete comparisons (eight vs. two, two vs. six, four vs. six) and two continuous comparisons (eight vs. two, eight vs. four). However, low accuracy may be attributable to difficulty in visual acuity exacerbated by difficulty discriminating quantities at small ratios. Furthermore, we found no evidence for a speed-accuracy trade-off in their decision-making process. Our results suggest that sleepy lizards likely employ multiple cues to estimate quantity accurately. Considering these results in the context of previous studies on various lizard species, it becomes apparent that lizards, as a group, offer a valuable model for unraveling the evolution of cognition, given their diverse ecology and sociobiology.

Assessing the impact of habitat and captivity status on volatilome profiles of the illegally traded shingleback, Tiliqua rugosa

Volatilomics is the study of the total biogenic volatile organic compounds (BVOCs) produced by an organism. This field has been used to assess organism and ecosystem health, as well as determine BVOC biomarkers for forensic purposes, including the detection of human remains, ignitable liquid residues and illicit drugs. For volatilomics to be applied in wildlife-victim casework (e.g. the illegal wildlife trade) a large reference database must be collected across each targeted species range. Adequate sample sizes must be collected from different habitats spanning across the species range of the targeted species to evaluate volatilome variability associated with different environmental and dietary characteristics. This will allow for assessment of chemical diversity and the determination of BVOC biomarkers that are relevant to wildlife forensic cases (e.g. detection, species identification, geographic origin assessment). This study collected the first live animal volatilome database, using the highly trafficked and widely distributed Australian shingleback lizard (Tiliqua rugosa). Optimised thermal desorption and analysis methods were used to examine 127 wild shingleback volatilome samples collected from sites across New South Wales, South Australia and Western Australia and 28 volatilome samples from captive shinglebacks. The results demonstrated that volatilome profiles and chemical diversity differed across each sampling region, potentially related to habitat and diet changes. At least 7 volatilome samples were required to capture chemical diversity in a sampling region. Forty-four tentatively identified BVOCs were shared across all sampling regions and captive animals which may aid in detection purposes. Bioregion-specific BVOCs were also identified, which will also aid in geographic assignment of confiscated individuals. This work demonstrates the importance of sample sizes in capturing chemical diversity within Bioregions prior to downstream volatilome analysis for the establishment of wildlife forensic databases and biomarker selection.

Ophidian Serpentoviruses: A Review and Perspective

Ophidian serpentoviruses, initially referred to as nidoviruses, were first documented in captive pythons nearly ten years ago. Since then, much has been learned about these important pathogens, now classified in subfamily Serpentovirinae of family Tobaniviridae and representing an important emerging pathogen that threatens captive snakes. Serpentoviral infections are best characterized in pythons (family Pythonidae), but have also been documented in boas (family Boidae) and colubrids (family Colubridae), as well as shingleback skinks (Tiliqua rugosa), veiled chameleons (Chamaeleo calyptratus), and the Bellinger River snapping turtle (Myuchelys georgesi). Clinical signs include increased oral mucous secretion, oral mucosal reddening, dyspnea, anorexia, and weight loss. Subclinical infections can also occur, and multiple studies report a lack of correlation between clinical signs and presence of serpentoviral nucleic acids in snakes. Lesions associated with serpentoviral infections predominantly occur in the upper respiratory and gastrointestinal tracts but can also extend to the lungs. Microscopically, these lesions may consist of inflammation, epithelial proliferation, and proliferative interstitial pneumonias, which can be complicated by concurrent bacterial bronchopneumonia. The most common method of diagnosis is reverse transcription PCR to detect viral RNA, and oral/choanal swabs are reliable samples for ante- or postmortem diagnosis. Specific treatment protocols have not yet been described, and management is based on supportive care. This manuscript presents a narrative review of all serpentovirus publications to date with perspective from researchers working to further characterize these pathogens, with the goal of serving as a comprehensive clinical and diagnostic overview for clinicians, zoological curatorial staff, wildlife biologists, and hobbyists.

Insights into the Effects of Violating Statistical Assumptions for Dimensionality Reduction for Chemical "-omics" Data with Multiple Explanatory Variables.

Biological volatilome analysis is inherently complex due to the considerable number of compounds (i.e., dimensions) and differences in peak areas by orders of magnitude, between and within compounds found within datasets. Traditional volatilome analysis relies on dimensionality reduction techniques which aid in the selection of compounds that are considered relevant to respective research questions prior to further analysis. Currently, compounds of interest are identified using either supervised or unsupervised statistical methods which assume the data residuals are normally distributed and exhibit linearity. However, biological data often violate the statistical assumptions of these models related to normality and the presence of multiple explanatory variables which are innate to biological samples. In an attempt to address deviations from normality, volatilome data can be log transformed. However, whether the effects of each assessed variable are additive or multiplicative should be considered prior to transformation, as this will impact the effect of each variable on the data. If assumptions of normality and variable effects are not investigated prior to dimensionality reduction, ineffective or erroneous compound dimensionality reduction can impact downstream analyses. It is the aim of this manuscript to assess the impact of single and multivariable statistical models with and without the log transformation to volatilome dimensionality reduction prior to any supervised or unsupervised classification analysis. As a proof of concept, Shingleback lizard (Tiliqua rugosa) volatilomes were collected across their species distribution and from captivity and were assessed. Shingleback volatilomes are suspected to be influenced by multiple explanatory variables related to habitat (Bioregion), sex, parasite presence, total body volume, and captive status. This work determined that the exclusion of relevant multiple explanatory variables from analysis overestimates the effect of Bioregion and the identification of significant compounds. The log transformation increased the number of compounds that were identified as significant, as did analyses that assumed that residuals were normally distributed. Among the methods considered in this work, the most conservative form of dimensionality reduction was achieved through analyzing untransformed data using Monte Carlo tests with multiple explanatory variables.

Predation attempt by a Southern Heath Monitor, Varanus rosenbergi (Varanidae), on a Western Shingleback Lizard, Tiliqua rugosa (Scincidae), in Southwest Australia

Predation attempt by a Southern Heath Monitor, Varanus rosenbergi (Varanidae), on a Western Shingleback Lizard, Tiliqua rugosa (Scincidae), in Southwest Australia

Biomechanical behaviour of lizard osteoderms and skin under external loading.

Many species of lizards are partially enveloped by a dermal armour made of ossified units called osteoderms. Lizard osteoderms demonstrate considerable species-specific variation in morphology and histology. Although a physical/protective role (against predators, prey, conspecifics and impact loading during falls) is frequently advanced, empirical data on the biomechanics of lizard osteoderms are scarce, limiting our understanding of form-function relationships. Here, we report deformation recorded at the surface of temporal osteoderms during controlled external loading of preserved specimens of 11 lizard species (Tiliqua rugosa, Tiliqua scincoides, Corucia zebrata, Pseudopus apodus, Timon lepidus, Matobosaurus validus, Broadleysaurus major, Tribolonotus gracilis, Tribolonotus novaeguineae, Heloderma horridum and Heloderma suspectum). Based on the strain recorded in situ and from isolated osteoderms, the skin of the species investigated can be ranked along a marked stiffness gradient that mostly reflects the features of the osteoderms. Some species such as T. rugosa and the two Heloderma species had very stiff osteoderms and skin while others such as T. lepidus and P. apodus were at the other end of the spectrum. Histological sections of the osteoderms suggest that fused (versus compound) osteoderms with a thick layer of capping tissue are found in species with a stiff skin. In most cases, loading neighbouring osteoderms induced a large strain in the instrumented osteoderm, attesting that, in most species, lizard osteoderms are tightly interconnected. These data empirically confirm that the morphological diversity observed in lizard osteoderms is matched by variability in biomechanical properties.

A forensically validated genetic toolkit for the species and lineage identification of the highly trafficked shingleback lizard (Tiliqua rugosa)

Shingleback lizards (Tiliqua rugosa) are among the most trafficked native fauna from Australia in the illegal pet trade. There are four morphologically recognised subspecies of shinglebacks, all with differing overseas market values. Shinglebacks from different geographic locales are often trafficked and housed together, which may complicate identifying the State jurisdiction where the poaching event occurred. Additionally, shinglebacks can be housed and trafficked with other species within the same genus, which may complicate DNA analysis, especially in scenarios where indirect evidence (e.g. swabs, faeces) is taken for analysis. In this study, a forensic genetic toolkit was designed and validated to target shingleback DNA for species identification and geographic origin. To do this, field sampling across Australia was conducted to expand the phylogeographic sampling of shinglebacks across their species range and include populations suspected to be poaching hotspots. A commonly used universal reptile primer set (ND4/LEU) was then validated for use in forensic casework related to the genus Tiliqua. Two additional ND4 primer sets were designed and validated. The first primer set was designed and demonstrated to preferentially amplify an ∼510 bp region of the genus Tiliqua over other reptiles and builds on existing data to expand the available phylogeographic database. The second primer set was designed and demonstrated to solely amplify an ∼220 bp region of T. rugosa ND4 over any other reptile species. Through the validation process, all primers were demonstrated to amplify T. rugosa DNA from a variety of sample types (e.g. degraded, low quality and mixed). Two of the primer sets were able to distinguish the genetic lineage of T. rugosa from the phylogeographic database. This work provides the first forensically validated toolkit and phylogeographic genetic database for Squatmate lizards.

No UV vision for trend-bucking blue-tongued skinks

Squaring up to an adversary is always risky; you could break a limb, suffer damaged skin, or lose scales if you're a lizard. However, blue-tongued skinks may have a less confrontational strategy for diffusing conflict: they waggle their tongues at each other. But these are no ordinary tongues. As the lizard's name suggests, they are blue. But what exactly does a blue-tongued skink opponent see when a rival flashes its tongue? Well, that depends on the light-sensing photoreceptors at the back of the lizard's eye and which shades the receptors are tuned to, yet no one had taken a close look at blue tongued skinks’ eyes to find out how the reptiles see colour. So, Nicolas Nagloo and Jan Hemmi from the University of Western Australia and colleagues decided to take a close look at the back of one blue-tongued skink's eyes – the sleepy lizard, Tiliqua rugosa – to begin to understand what the animals see when a threatening rival waggles its tongue.It turns out that the reptile's eyes are more sensitive to shades of blue than other lizards and when the team checked for the essential light-sensitive proteins (photopigments) that specifically tune light-sensitive photoreceptors to certain shades of colour (wavelengths of light), they discovered that the sleepy lizard's eye has five types of photopigment: two tuned to shades of blue, two to shades of green and a fifth that picks up yellowy shades of green. Yet, when the team measured the electrical signals produced by the sleepy lizards’ retina, the blue-tongued skinks were barely able to see ultraviolet wavelengths, which are clearly sensed by other lizards that see ultraviolet light beyond the rainbow we know.However, the team is still a long way from understanding what the lizards truly see when another sleepy lizard shoots out its tongue. It is not clear which shades the blue-sensitive photopigments in the eye are precisely tuned to and how natural light filters formed by oil drops in the retina might modify the lizard's colour vision. But it is clear that the blue-tongued skinks see colours in a very different way from other lizards, which have a visual pallet that extends into the ultraviolet. Whether the sleepy lizard's lurid tongue or restricted colour vision range came first is also not apparent, but it is clear that various factors have moulded the blue-tongued skink's vision to be distinctly different from that of other lizards.

Enhanced short-wavelength sensitivity in the blue-tongued skink Tiliqua rugosa.

ABSTRACTDespite lizards using a wide range of colour signals, the limited variation in photoreceptor spectral sensitivities across lizards suggests only weak selection for species-specific, spectral tuning of photoreceptors. Some species, however, have enhanced short-wavelength sensitivity, which probably helps with the detection of signals rich in ultraviolet and short wavelengths. In this study, we examined the visual system of Tiliqua rugosa, which has an ultraviolet/blue tongue, to gain insight into this species' visual ecology. We used electroretinograms, opsin sequencing and immunohistochemical labelling to characterize whole-eye spectral sensitivity and the elements that shape it. Our findings reveal that T. rugosa expresses all five opsins typically found in lizards (SWS1, SWS2, RH1, RH2 and LWS) but possesses greatly enhanced short-wavelength sensitivity compared with other diurnal lizards. This enhanced short-wavelength sensitivity is characterized by a broadening of the spectral sensitivity curve of the eye towards shorter wavelengths while the peak sensitivity of the eye at longer wavelengths (560 nm) remains similar to that of other diurnal lizards. While an increased abundance of SWS1 photoreceptors is thought to mediate elevated ultraviolet sensitivity in a couple of other lizard species, SWS1 photoreceptor abundance remains low in this species. Instead, our findings suggest that short-wavelength sensitivity is driven by multiple factors which include a potentially red-shifted SWS1 photoreceptor and the absence of short-wavelength-absorbing oil droplets. Examining the coincidence of enhanced short-wavelength sensitivity with blue tongues among lizards of this genus will provide further insight into the co-evolution of conspecific signals and whole-eye spectral sensitivity.

Intrinsic traits, social context, and local environment shape home range size and fidelity of sleepy lizards

AbstractHome ranges (HRs), the regions within which animals interact with their environment, constitute a fundamental aspect of their ecology. HR sizes and locations commonly reflect costs and benefits associated with diverse social, biotic, and abiotic factors. Less is known, however, about how these factors affect intraspecific variation in HR size or fidelity (the individual's tendency to maintain the same HR location over time) or whether variation in these features emerge from consistent differences among individuals or among the sites they occupy. To address this knowledge gap, we used an extensive GPS‐tracking data set of a long‐lived lizard, the sleepy lizard (Tiliqua rugosa), which included repeated observations of multiple individuals across years. We tested how three categories of predictors—(1) lizard characteristics (sex, aggressiveness, and parasitic tick counts), (2) environmental characteristics (precipitation, food, and refuge quality), and (3) social conditions (conspecific overlap and number of neighbors)—affected HR size and fidelity. We found that individuals differed consistently in the size and fidelity of annual HRs (with a repeatability of 0.58 and 0.33, respectively), and that all three categories of predictors affected both HR size and fidelity. For example, HRs were smaller in areas with more food, and males had larger HRs than females. In addition, more aggressive lizards tended to have larger HRs. Conspecific overlap and number of individuals that a lizard interacted with (social network degree) had an interactive effect on HR size where individuals whose HRs overlapped more with neighbors had larger HRs, and this effect was particularly strong for individuals that interacted with more neighbors. HR fidelity declined over time (HR locations drifted from year to year), but individuals differed consistently in this rate of drift. The fact that HR size was consistent despite drifting locations suggests that lizard HRs reflect individual traits (e.g., habitat choice criteria that differ among individuals), rather than simple heterogeneity among sites. Overall, these findings demonstrate (1) both strong, long‐term, within‐individual consistency and between‐individual differences in space use and (2) combined effects of individual traits, social conditions, and environmental characteristics on animal HRs, with implications for diverse ecological processes.

Vegetation cover and configuration drive reptile species distributions in a fragmented landscape

Context Habitat loss and fragmentation are key drivers of biodiversity loss worldwide, yet the influence of landscape structure on species distributions is unknown. Globally, reptiles are thought to be especially sensitive to landscape modification due to their limited capacity for dispersal and reliance on native vegetation. New knowledge of how landscape structure influences species distributions is needed to inform conservation strategies. Aims Our principal aim was to examine the influence of landscape structure on the distributions of 40 terrestrial reptile species in Victoria, southeast Australia. Methods We obtained species occurrence records from the Victorian Biodiversity Atlas, and used MaxEnt to model the distributions of reptile species within Victoria using biophysical and landscape structure variables. A moving window analysis was applied to a land cover map to derive five landscape structure metrics; two metrics represented landscape cover and three represented landscape configuration. Key results Climate variables were generally found to be the strongest drivers of species distributions, although 80% of reptile species were also influenced by landscape structure (permutation importance ≥5%). Of the five landscape structure variables, extent of native vegetation had the greatest influence (30 of 40 species), followed by habitat shape. For Lerista bougainvillii and Tiliqua rugosa, native vegetation cover had a greater influence on their distributions than climate variables. Most species responded positively to native vegetation extent, whereas responses to other landscape structure variables were varied. Conclusions Although most studies of reptile distributions only use biophysical variables in modelling, our research shows that at the scale of our study area, reptile species distributions were also influenced by landscape structure; extent of native vegetation was an important predictor for most species. Integrating landscape structure in modelling has the potential to improve our ability to predict species distributions. Implications Because species distributions are likely to shift due to climate change, knowledge of the influence of landscape structure on distributions will help land managers to facilitate successful range expansions in fragmented landscapes. Our findings indicate that management focused on increasing the extent of native vegetation is likely to provide benefit to most reptile species.

Revealing mechanisms of infectious disease spread through empirical contact networks.

The spread of pathogens fundamentally depends on the underlying contacts between individuals. Modeling the dynamics of infectious disease spread through contact networks, however, can be challenging due to limited knowledge of how an infectious disease spreads and its transmission rate. We developed a novel statistical tool, INoDS (Identifying contact Networks of infectious Disease Spread) that estimates the transmission rate of an infectious disease outbreak, establishes epidemiological relevance of a contact network in explaining the observed pattern of infectious disease spread and enables model comparison between different contact network hypotheses. We show that our tool is robust to incomplete data and can be easily applied to datasets where infection timings of individuals are unknown. We tested the reliability of INoDS using simulation experiments of disease spread on a synthetic contact network and find that it is robust to incomplete data and is reliable under different settings of network dynamics and disease contagiousness compared with previous approaches. We demonstrate the applicability of our method in two host-pathogen systems: Crithidia bombi in bumblebee colonies and Salmonella in wild Australian sleepy lizard populations. INoDS thus provides a novel and reliable statistical tool for identifying transmission pathways of infectious disease spread. In addition, application of INoDS extends to understanding the spread of novel or emerging infectious disease, an alternative approach to laboratory transmission experiments, and overcoming common data-collection constraints.

Personality, spatiotemporal ecological variation and resident/explorer movement syndromes in the sleepy lizard.

Individual variation in movement is profoundly important for fitness and offers key insights into the spatial and temporal dynamics of populations and communities. Nonetheless, individual variation in fine-scale movement behaviours is rarely examined even though animal tracking devices offer the long-term, high-resolution, repeatable data in natural conditions that are ideal for studying this variation. Furthermore, of the few studies that consider individual variation in movement, even fewer also consider the internal traits and environmental factors that drive movement behaviour which are necessary for contextualising individual differences in movement patterns. In this study, we GPS tracked a free-ranging population of sleepy lizards Tiliqua rugosa, each Austral spring over 5years to examine consistent among-individual variation in movement patterns, as well as how these differences were mediated by key internal and ecological factors. We found that individuals consistently differed in a suite of weekly movement traits, and that these traits strongly covaried among-individuals, forming movement syndromes. Lizards fell on a primary movement continuum, from 'residents' that spent extended periods of time residing within smaller core areas of their home range, to 'explorers' that moved greater distances and explored vaster areas of the environment. Importantly, we also found that these consistent differences in lizard movement were related to two ecologically important animal personality traits (boldness and aggression), their sex, key features of the environment (including food availability, and a key water resource), habitat type and seasonal variation (cool/moist vs. hot/drier) in environmental conditions. Broadly, these movement specialisations likely reflect variation in life-history tactics including foraging and mating tactics that ultimately underlie key differences in space use. Such information can be used to connect phenotypic population structure to key ecological and evolutionary processes, for example social networks and disease-transmission pathways, further highlighting the value of examining individual variation in movement behaviour.

A mammal tick with a taste for lizard blood: Parasitism by the kangaroo soft tick, (Ornithodoros gurneyi) on sleepy lizards (Tiliqua rugosa)

The kangaroo soft tick (Ornithodoros gurneyi) inhabits xeric habitats of Australia and, as a result, little is known about the natural hosts of the different life stages of this tick. Large macropods are inferred as the kangaroo soft tick's principal hosts since all life stages inhabit the loose soil of kangaroo wallows. These ticks have been reported to parasitize bearded dragons (Pogona barbata) and sleepy lizards (Tiliqua rugosa), however it is not known whether these lizards are competent hosts of this tick. In this study the prevalence and intensity of O. gurneyi parasitism on T. rugosa was examined by sampling lizards at a long-term study site spanning a precipitation-induced ecological gradient. The competence of T. rugosa as a host for O. gurneyi was explored by keeping larvae and nymphs of O. gurneyi, that had fed on T. rugosa, in captivity to determine if they will survive and moult. We found that O. gurneyi occurs throughout the study site, but that they were seldom recorded to parasitise T. rugosa. Still, it was noted that T. rugosa is a competent host of O. gurneyi. The results of this study indicate that kangaroos are not the only competent hosts of O. gurneyi and raises the question of whether T. rugosa and other lizards may play a role in the dispersal of these ticks.

Behavioural ecology of the Sleepy Lizard

Behavioural ecology of the Sleepy Lizard

Strengthening protection of endemic wildlife threatened by the international pet trade: The case of the Australian shingleback lizard

AbstractUnsustainable wildlife trade threatens an increasing number of species globally. Australia has a particularly rich and endemic herpetofauna, which is coveted on the international pet market. While Australia implements domestic protection of most of its native species, there is little to no regulation of international trade once live animals have been smuggled out of the country. This is a threat for a variety of rare, unique and/or range‐restricted species, subspecies and locality morphs. One of these species is the shingleback lizard (Tiliqua rugosa).We compiled Australian seizure data and international online trade data pertaining to shinglebacks. We found all four subspecies in trade across Asia, Europe and North America. Here we provide evidence that all four shingleback subspecies are illegally extracted from the wild in Australia and smuggled to international destinations, where they are sold and distributed globally.While shinglebacks are a protected species in Australia and can only be exported legally under a federal permit, their import into, and trade between, other countries is often not illegal, even in the absence of such a permit. These contradictory legal frameworks apply to the majority of nationally protected native fauna and must be addressed by each importing country on an individual basis; that is, by changing their legislation to cover and protect species that are nationally protected in their native range. Meanwhile, however, we argue that listingT. rugosain Appendix III of the Convention on International Trade in Endangered Species of Wild Fauna and Flora is a meaningful way to provide other countries with the legal means to confiscate illegally exported shinglebacks from Australia. Our findings and recommendations are directly relevant for potential future Appendix III consideration of other nationally protected species that are found in international trade.