Aim Species with temperature‐dependent sex determination (TSD) are particularly vulnerable to climate change because a resultant skew in population sex ratio can have severe demographic consequences and increase vulnerability to local extinction. The Australian central bearded dragon (Pogona vitticeps) has a thermosensitive ZZ male/ZW female system of genetic sex determination (GSD). High incubation temperatures cause reversal of the ZZ genotype to a viable female phenotype. Nest temperatures in the wild are predicted to vary on a scale likely to produce heterogeneity in the occurrence of sex reversal, and so we predict that sex reversal will correlate positively with inferred incubation conditions. Location Mainland Australia. Methods Wild‐caught specimens of P. vitticeps vouchered in museum collections and collected during targeted field trips were genotypically and phenotypically sexed to determine the distribution of sex reversal across the species range. To determine whether environmental conditions or genetic structure can explain this distribution, we infer the incubation conditions experienced by each individual and apply a multi‐model inference approach to determine which conditions associate with sex reversal. Further, we conduct reduced representation sequencing on a subset of specimens to characterize the population structure of this broadly distributed species. Results Here we show that sex reversal in this widespread Australian dragon lizard is spatially restricted to the eastern part of the species range. Neither climatic variables during the inferred incubation period nor geographic population genetic structure explain this disjunct distribution of sex reversal. The main source of genetic variation arose from isolation by distance across the species range. Main conclusions We propose that local genetic adaptation in the temperature threshold for sex reversal can counteract the sex‐reversing influence of high incubation temperatures in P. vitticeps. Our study demonstrates that complex evolutionary processes need to be incorporated into modelling biological responses to future climate scenarios.

Assessment of non-target impacts of pesticides used widely in agriculture and pest management rarely considers reptiles. Despite their integral role in all ecosystems, particularly arid ecosystems, reptiles are not included in risk assessments. Two pesticides used in agricultural pest management are fipronil and fenitrothion. Here, we used a field-based BACI design experiment in semi-arid Australia to investigate the impact of these pesticides on basic physiological and behavioural parameters of a common arid-zone lizard species, Pogona vitticeps. Fipronil and fenitrothion were applied at ecologically relevant doses via oral gavage. Before and after dosing, blood, physical activity and body condition parameters were assessed. We found that temperature significantly influenced lizard activity in the morning period of movement; however, fipronil-treated individuals moved at least 49% less than fenitrothion-treated and control lizards from 7 days after dosing through to the end of the experiment. Physiological measures did not change significantly before or after exposure to both pesticides; however, other indicators showed evidence of exposure, which remained for the entirety of our monitoring period. On average, cholinesterase inhibition was still >30% compared with control lizards at the end of 4 weeks, and fipronil sulfone blood residues remained at 0.219 μg/ml. Our study provides novel insights into the impacts that common pesticides have on widespread lizard species. We show that an ecologically relevant low dose of fipronil alters the behaviour of P. vitticeps, which has the potential to impact longer-term survivability. Persistence of both pesticides in the blood of all treatment lizards throughout the experiment indicates they are unable to clear these toxins within a month of being exposed. This may be significant for compounding exposure and latent toxicity. These findings highlight the susceptibility that reptiles have to a selection of common pesticides and the inherent need for higher prominence in wildlife ecotoxicological research.

Context Quantifying the space use and movement patterns of animals is important to understand other aspects of a species ecology, such as habitat use and social systems. However, basic data on space use and movement patterns, and how they are influenced by biotic or abiotic factors, are lacking for many species. Aims We identified the space use and movement patterns of the central bearded dragon (Pogona vitticeps), and assessed how external factors (environmental conditions) and internal factors (sex and morphology) shape these patterns. Methods We tracked 36 P. vitticeps individuals over three seasons from 2017 to 2018. Animals carried tags with a Global Positioning Systems (GPS) device to collect spatial data and an accelerometer to collect movement data in far western New South Wales, Australia. Measurements of body morphology were taken for each individual and ambient temperatures were recorded. Space use was analysed by calculating minimum convex polygons (MCPs) and kernel density estimates (KDEs) using the spatial data. Movement data were analysed to determine whether dragons had moved during 10-min periods. Results Twenty-three out of 36 individuals held defined activity areas. Males with wider tails were most likely to be floaters (i.e. not restricted to specific areas). Evidence of floater behaviour was shown by 45% of females and 20% of males, though both sexes often roamed over distances greater than 1 km. Air temperatures strongly influenced movement rates in both sexes. Movement rate was significantly higher for males than females during late-spring, but not mid-summer, and was inversely related to head sizes and body mass during mid-summer. Interestingly, although there was no correlation observed between daily movement rates and size of MCPs calculated, the movement rates of residents were significantly different from floaters for each season. Conclusions These results confirm that wild P. vitticeps movement patterns are driven by temperature, though space-use patterns vary from previously studied agamids, with high rates of nomadism, possibly due to drought conditions. Individuals varied widely in their space-use tactics, which seem unrelated to size, a potential proxy for social status or age. Implications Our study provides baseline information on a common arid zone agamid that is lacking research in the wild. More complex studies on the ecology of P. vitticeps can build on the findings of this study.

The relationship between sublethal pesticide exposure and oxidative stress in an ecologically relevant field setting is relatively unknown for reptiles. Oxidative stress is a multi-faceted concept that dictates key survival and fitness parameters in any organism. Fipronil and fenitrothion are two pesticides widely used globally for agricultural pest management. Using a field-based, BACI designed experiment we investigated the impact of sublethal pesticide exposure on oxidative stress biomarkers protein carbonyl and DNA damage (8-OHdG), in an arid-zone lizard species, Pogona vitticeps. A single ecologically relevant dose of pesticide was applied via oral gavage to treatment animals. Lizard condition, activity measures, and blood biomarkers were measured at relevant sampling intervals. Cholinesterase (ChE) and acetylcholinesterase (AChE) enzymatic biomarkers were measured in response to fenitrothion, and fipronil blood residues were measured for fipronil-treated lizards. Results suggested no significant treatment effect of either pesticide on parameters measured, however, 8-OHdG levels decreased by ≥ 45% for both pesticide treatment groups and not controls. Protein carbonyl levels showed a high degree of individual variation that proved more influential than pesticide exposure. Building our understanding of the macromolecular impacts of sublethal pesticide exposure on wild lizard populations is an integral step in addressing the current gap in literature and management practices. Our study has also highlighted the complex nature of studying oxidative stress in the field and the sheer necessity of future study.