Microbial communities are thermally more sensitive in warm-climate lizards compared with their cold-climate counterparts.

Environmental temperature affects the composition, structure, and function of the gut microbial communities in host animals. To elucidate the role of gut microbiota in thermal adaptation, we designed a 2 species × 3 temperatures experiment, whereby we acclimated adult males of two agamid lizard species (warm-climate Leiolepis reevesii and cold-climate Phrynocephalus przewalskii) to 20, 28, and 36°C for 2 weeks and then collected their fecal and small-intestinal samples to analyze and compare the microbiota using 16S rRNA gene amplicon sequencing technology. The fecal microbiota displayed more pronounced interspecific differences in microbial community than the small-intestinal microbiota in the two species occurring in thermally different regions. The response of fecal and small-intestinal microbiota to temperature increase or decrease differed between the two species, with more bacterial taxa affected by acclimation temperature in L. reevesii than in P. przewalskii. Both species, the warm-climate species in particular, could cope with temperature change by adjusting the relative abundance of functional categories associated with metabolism and environmental information processing. Functional genes associated with carbohydrate metabolism were enhanced in P. przewalskii, suggesting the contribution of the fecal microbiota to cold-climate adaptation in P. przewalskii. Taken together, our results validate the two hypotheses tested, of which one suggests that the gut microbiota should help lizards adapt to thermal environments in which they live, and the other suggests that microbial communities should be thermally more sensitive in warm-climate lizards than in cold-climate lizards.

Genome-wide characterization of the TGF-ß gene family and their expression in different tissues during tail regeneration in the Schlegel's Japanese gecko Gekko japonicus.

The transforming growth factor-ß (TGF-ß) gene family is unique to animals and is involved in various important processes including tissue regeneration. Here, we identified 52 TGF-ß family genes based on genome sequences of the gecko (Gekko japonicus), compared TGF-ß genes between G. japonicus and other four reptilian species, and evaluated the expression of 14 randomly selected genes in muscle, kidney, liver, heart, and brain during tail regeneration to investigate whether their expression was tissue-dependent. We detected 23 conserved domains, 13 in the TGF-ß ligand subfamily, and 10 in the receptor subfamily. The pattern of higher genetic variation in the ligand subfamily than in the receptor subfamily in vertebrates might result from the precise localization of agonists and antagonists in the cell surface and intracellular compartment. TGF-ß genes were unevenly distributed across 15 chromosomes in G. japonicus, presumably resulting from gene losses and gains during evolution. Genes in the TGF-ß receptor subfamily (ACVR2A, ACVR2B, ACVR1, BMPR1A, ACVRL1, BMPR2 and TGFBR1) played a vital role in the TGF-ß signal pathway. The expression of all 14 randomly selected TGF-ß genes was tissue-specific. Our study supports the speculation that some TGF-ß family genes are involved in the early stages of tail regeneration.

Genomic insights into local adaptation in the Asiatic toad Bufo gargarizans, and its genomic offset to climate warming.

Genomic signatures of local adaptation have been identified in many species but remain sparsely studied in amphibians. Here, we explored genome-wide divergence within the Asiatic toad, Bufo gargarizans, to study local adaptation and genomic offset (i.e., the mismatch between current and future genotype-environment relationships) under climate warming scenarios. We obtained high-quality SNP data for 94 Asiatic toads from 21 populations in China to study spatial patterns of genomic variation, local adaptation, and genomic offset to warming in this wide-ranging species. Population structure and genetic diversity analysis based on high-quality SNPs revealed three clusters of B. gargarizans in the western, central-eastern, and northeastern portions of the species' range in China. Populations generally dispersed along two migration routes, one from the west to the central-east and one from the central-east to the northeast. Both genetic diversity and pairwise F ST were climatically correlated, and pairwise F ST was also correlated with geographic distance. Spatial genomic patterns in B. gargarizans were determined by the local environment and geographic distance. Global warming will increase the extirpation risk of B. gargarizans.

The functional significance of residual yolk in lizards.

Residual yolk is assumed to be an important source of energy and nutrients during early life in nonmammalian amniotes. Available data show that the mean size of residual yolk is far smaller in lizards than in turtles, snakes, crocodiles, and birds, raising a question of whether residual yolk is of functional significance in lizards. Here, we compared data from 26 lizard species with those from other nonmammalian amniotes to test the hypothesis that residual yolk is functionally less significant in species producing more fully developed offspring. In our sample, species mean offspring water contents ranged from 73% to 84% of body wet mass; species mean proportions of carcass dry mass, fat-body dry mass, and residual yolk dry mass to offspring dry mass ranged from 84% to 99%, 0% to 5.0%, and 0% to 14.4%, respectively. Lizards are, on average, more fully developed at hatching or birth than snakes, as revealed by the fact that the mean proportion of carcass dry mass to body dry mass and offspring water contents were both higher in lizards than in snakes. We conclude that the functional significance of residual yolk during early life is generally less evident in lizards. Even in the lizards where residual yolk is of potential functional significance, this portion of yolk contributes little, if any, to postembryonic growth. Future work could usefully collect data across a wider spectrum of reptile taxa to establish a precocial-altricial continuum and test the hypothesis that species with a smaller amount of residual yolk are closer to the precocial end of the continuum.

Dietary and Sexual Correlates of Gut Microbiota in the Japanese Gecko, Gekko japonicus (Schlegel, 1836).

Numerous studies have demonstrated that multiple intrinsic and extrinsic factors shape the structure and composition of gut microbiota in a host. The disorder of the gut microbiota may trigger various host diseases. Here, we collected fecal samples from wild-caught Japanese geckos (Gekko japonicus) and captive conspecifics fed with mealworms (mealworm-fed geckos) and fruit flies (fly-fed geckos), aiming to examine the dietary and sexual correlates of the gut microbiota. We used 16S rRNA gene sequencing technology to determine the composition of the gut microbiota. The dominant phyla with a mean relative abundance higher than 10% were Verrucomicrobiota, Bacteroidota, and Firmicutes. Gut microbial community richness and diversity were higher in mealworm-fed geckos than in wild geckos. Neither community evenness nor beta diversity of gut microbiota differed among wild, mealworm-fed, and fly-fed geckos. The beta rather than alpha diversity of gut microbiota was sex dependent. Based on the relative abundance of gut bacteria and their gene functions, we concluded that gut microbiota contributed more significantly to the host's metabolic and immune functions. A higher diversity of gut microbiota in mealworm-fed geckos could result from higher chitin content in insects of the order Coleoptera. This study not only provides basic information about the gut microbiota of G. japonicus but also shows that gut microbiota correlates with dietary habits and sex in the species.

Gut microbiota differs between two cold-climate lizards distributed in thermally different regions.

BACKGROUND: The metabolic cold-climate adaption hypothesis predicts that animals from cold environments have relatively high metabolic rates compared with their warm-climate counterparts. However, studies testing this hypothesis are sparse. Here, we compared gut microbes between two cold-climate lizard species of the genus Phrynocephalus to see if gut microbiota could help lizards adapt to cold environments by promoting metabolism. We conducted a 2 species (P. erythrurus and P. przewalskii) × 2 temperatures (24 and 30 °C) factorial design experiment, whereby we kept lizards of two Phrynocephalus species at 24 and 30 °C for 25 d and then collected their fecal samples to analyze and compare the microbiota based on 16S rRNA gene sequencing technology. RESULTS: The gut microbiota was mainly composed of bacteria of the phyla Proteobacteria, Firmicutes, Bacteroidetes, and Verrucomicrobia in both species (Proteobacteria > Firmicutes > Verrucomicrobiota in P. erythrurus, and Bacteroidetes > Proteobacteria > Firmicutes in P. przewalskii). Further analysis revealed that the gut microbiota promoted thermal adaptation in both lizard species, but with differences in the relative abundance of the contributory bacteria between the two species. An analysis based on the Kyoto Encyclopedia of Genes and Genomes revealed that the gut microbiota played important roles in metabolism, genetic information processing, cellular processes, and environmental information processing in both species. Furthermore, genes related to metabolism were more abundant in P. erythrurus at 24 °C than in other species ⋅ temperature combinations. CONCLUSION: Our study provides evidence that gut microbiota promotes thermal adaptation in both species but more evidently in P. erythrurus using colder habitats than P. przewalskii all year round, thus confirming the role of gut microbiota in cold-climate adaptation in lizards.

Single-cell transcriptomes from turtle livers reveal sensitivity of hepatic immune cells to bacteria-infection.

The liver is important in the synthesis, metabolism and storage of nutrients, detoxification and immune response of the body, and the liver immune response against exogenous pathogens from the intestinal tract plays a key role in the immune activities. However, the cellular composition of the liver immune atlas remains sparsely studied in reptiles. We used single-cell RNA sequencing to identify the cellular profile of the liver of the Chinese soft-shelled turtle (Pelodiscus sinensis). We obtained the transcriptional landscape based on 9938 cells from the fractionation of fresh hepatic tissues from two individuals, uninfected and infected with bacteria (Aeromonas hydrophila). We identified seven hepatic immune cell subsets, including plasma, erythroid, T/NK, B, endothelial, dendritic and Kupffer cells. Bacteria-infection altered the number of liver immune cells, as revealed by the fact that the infected turtle had more plasma, endothelial and Kupffer cells and fewer T/NK, dendritic and erythroid cells than did the uninfected turtle. Our study is the first to provide a comprehensive view of the hepatic immune landscape of P. sinensis at the single-cell resolution that outlines the characteristics of immune cells in the turtle liver and provides a liver transcriptome baseline for turtle immunology.

Measuring Annual Variation in Reproductive Output Reveals a Key Role of Maternal Body Condition in Determining the Size of Eggs in Snakes.

Long-term studies are especially suited for disentangling the effects of extrinsic and intrinsic factors on both total reproductive investment and reproductive allocation in offspring number versus offspring size. Female reproductive traits of the red-banded wolf snake (Lycodon rufozonatus) from Zhejiang, East China were studied in four years between 1999 and 2014. Egg-laying dates overall extended from late June to late July, and varied among years. Postpartum body mass, clutch size, clutch mass, and egg size were positively related to female size (snout vent length, SVL) in each year. Postpartum body mass, clutch mass, and egg size differed among years after accounting for female SVL, whereas clutch size did not. Setting female SVL at the same level, postpartum body mass was greater in 2010 than in 2014, clutch mass was greater in 2010 than in 2011 and 2014, and egg size was greater in 2010 than in the other three years. Females did not trade off egg size against number. Egg size was positively related to postpartum body condition in each year. Females laid larger eggs in 2010 than in other three years after removing the influence of maternal body condition. Our study provides evidence for the traditional view that reproductive output is highly linked to maternal body size in snakes, but not following Smith and Fretwell's (1974) classic prediction that females with different amounts of resources to invest in reproduction should give priority to adjusting the number rather than size of their offspring. Maternal body size and condition both are important sources of variation in egg size, but factors other than these two variables may also affect the size of eggs produced by female L. rufozonatus.

Comparative study on gut microbiota in three Anura frogs from a mountain stream.

Composition and diversity in gut microbiota are impacted by a wide variety of factors. The similarity of gut microbiota in related or sympatric species has been gaining recent traction. Here, 16S rRNA gene sequencing technology was employed to study the gut microbiota of three sympatric frog species, namely Odorrana tormota, O. graminea, and Amolops wuyiensis. In these three frog species, the most abundant phylum was Proteobacteria, followed by Bacteroidetes, Verrucomicrobia, and Firmicutes. The most abundant family was Burkholderiaceae in three species. The most dominant genera were Burkholderia, Caballeronia, and Paraburkholderia with the highest relative abundance in O. tormota, O. graminea, and A. wuyiensis, respectively. No differences were observed in alpha diversity indexes among the three frog species. However, bacterial similarity of gut microbiota was significantly different between O. tormota and A. wuyiensis and between O. graminea and A. wuyiensis. Metabolism-related gene function was predominantly enriched in the gut microbiota of the three evaluated frog species. From these findings, that the relative abundance of the gut microbiota and predicted gene functions differed in three species, we conclude that there were significant differences in the gut microbiota of the three species. Similar alpha diversity and interspecific bacterial similarity in the gut might be related to bacterial transmission among the three Anura frogs evaluated in this study.

Geological and climatic influences on population differentiation of the Phrynocephalus vlangalii species complex (Sauria: Agamidae) in the northern Qinghai-Tibet Plateau.

Extremely heterogeneous topography and complex paleoclimatic history of the Qinghai-Tibet Plateau (QTP) have a key role in promoting genetic divergence among populations and lineage/species formation. Here, we sequenced one nuclear and three mitochondrial markers of 532 individuals from the entire range of the Phrynocephalus vlangalii species complex including two species, P. putjatai and P. vlangalii, endemic to the northern QTP. We integrated multilocus phylogeny, demographic analysis and geographic barrier detection to evaluate the population structure and dynamics. We found a new mitochondrial clade (PV-I) in the Gonghe County population of P. vlangalii, partial mitochondrial DNA replacement within P. vlangalii and complete mitochondrial DNA replacement between P. putjatai and P. vlangalii. Neutrality test, mismatch distribution analysis and Extended Bayesian Skyline Plot (EBSP) analysis all supported a significant expansion of the Qaidam Basin population of P. vlangalii (PV-II-2) from 0.091 to 0.026 Ma after Penultimate Glaciation. The uplift of the Arjin and Anyemanqen Mountains during the Kunhuang Movement (∼1.2 Ma) split populations of P. vlangalii in Akesai, Qaidam Basin and source of the Yellow River. The uplift of the Elashan Mountains during the second phase of the Qingzang Movement (∼2.5 Ma) contributed to the divergence of the Gonghe County population of P. vlangalii from other conspecific populations. The third phase of the Qingzang Movement (∼1.7 Ma) contributed to the divergence of the Xinghai population of P. vlangalii from P. putjatai and to the divergence of the northern populations of P. putjatai from the southern conspecific populations. Our data support the idea that the geological and climatic changes following the orogeny of the QTP may have promoted population differentiation and shaped the current population patterns of the P. vlangalii species complex in the northeastern QTP.

Large-scale evolution of body temperatures in land vertebrates.

Body temperature is a crucial variable in animals that affects nearly every aspect of their lives. Here we analyze for the first time largescale patterns in the evolution of body temperatures across terrestrial vertebrates (tetrapods: including amphibians, mammals, birds and other reptiles). Despite the traditional view that endotherms (birds and mammals) have higher body temperatures than ectotherms, we find they are not significantly different. However, rates of body-temperature evolution are significantly different, with lower rates in endotherms than ectotherms, and the highest rates in amphibians. We find that body temperatures show strong phylogenetic signal and conservatism over 350 million years of evolutionary history in tetrapods, and some lineages appear to have retained similar body temperatures over time for hundreds of millions of years. Although body temperatures are often unrelated to climate in tetrapods, we find that body temperatures are significantly related to day-night activity patterns. Specifically, body temperatures are generally higher in diurnal species than nocturnal species, both across ectotherms and, surprisingly, across endotherms also. Overall, our results suggest that body temperatures are significantly linked to phylogeny and diel-activity patterns within and among tetrapod groups, rather than just climate and the endotherm-ectotherm divide.

Venom of the Annulated Sea Snake Hydrophis cyanocinctus: A Biochemically Simple but Genetically Complex Weapon.

Given that the venom system in sea snakes has a role in enhancing their secondary adaption to the marine environment, it follows that elucidating the diversity and function of venom toxins will help to understand the adaptive radiation of sea snakes. We performed proteomic and de novo NGS analyses to explore the diversity of venom toxins in the annulated sea snake (Hydrophis cyanocinctus) and estimated the adaptive molecular evolution of the toxin-coding unigenes and the toxicity of the major components. We found three-finger toxins (3-FTxs), phospholipase A2 (PLA2) and cysteine-rich secretory protein (CRISP) in the venom proteome and 59 toxin-coding unigenes belonging to 24 protein families in the venom-gland transcriptome; 3-FTx and PLA2 were the most abundant families. Nearly half of the toxin-coding unigenes had undergone positive selection. The short- (i.p. 0.09 µg/g) and long-chain neurotoxin (i.p. 0.14 µg/g) presented fairly high toxicity, whereas both basic and acidic PLA2s expressed low toxicity. The toxicity of H. cyanocinctus venom was largely determined by the 3-FTxs. Our data show the venom is used by H. cyanocinctus as a biochemically simple but genetically complex weapon and venom evolution in H. cyanocinctus is presumably driven by natural selection to deal with fast-moving prey and enemies in the marine environment.

Climate warming will increase chances of hybridization and introgression between two Takydromus lizards (Lacertidae).

Coexisting species may experience population and range changes alone or jointly in response to environmental change. Here, we used six climate variables and ten modeling algorithms to predict the distribution of two Takydromus species (T. septentrionalis and T. sexlineatus) in China. We identified the sympatric and allopatric areas by comparing projections between the two species based on habitat suitability under present and future climate scenarios. We constructed the hypervolumes of six climate variables for the two species and then evaluated overlaps between hypervolumes. From this study, we know the following. First, minimum temperature of coldest month contributes the most to the prediction of habitat suitability. Second, habitats suitable for the two species will shift northward in response to climate warming. Third, the range of T. sexlineatus will expand across the four future time intervals before 2,100, namely the 2021-2040, 2041-2060, 2061-2080, and 2081-2100 intervals, under both Shared socioeconomic pathway (SSP) 245 and SSP585 scenarios, and the range of T. septentrionalis will also expand in the future except at the 2081-2100 interval under the SSP585 scenario. Fourth, the sympatric areas will contract or expand under the SSP245 scenario and expand across the four future time intervals before 2,100 under the SSP585 scenario. Fifth, the niche hypervolumes of the two species partially overlapped, and the differences in niche centroid show some degree of niche differentiation between the two species. These results allow to conclude that climate warming will not only drive the northward drift of sympatric areas but also increase the size of these areas if nothing is done to limit the emission of greenhouse gases. Given the existence of hybridization and introgression between T. septentrionalis and T. sexlineatus in the field where they coexist, we also conclude that climate warming will increase chances of hybridization and introgression between the two species.

Looking at the past to infer into the future: Thermal traits track environmental change in Liolaemidae.

The diversity of habitats generated by the Andes uplift resulted a mosaic of heterogeneous environments in South America for species to evolve a variety of ecological and physiological specializations. Species in the lizard family Liolaemidae occupy a myriad of habitats in the Andes. Here, we analyze the tempo and mode of evolution in the thermal biology of liolaemids. We assessed whether there is evidence of local adaptation (lability) or conservatism (stasis) in thermal traits. We tested the hypothesis that abiotic factors (e.g., geography, climate) rather than intrinsic factors (egg-laying [oviparous] or live-bearing [viviparous], substrate affinity) explain variation in field active body temperature (Tb ), preferred temperature (Tp ), hours of restriction of activity, and potential hours of activity. Although most traits exhibited high phylogenetic signal, we found variation in thermal biology was shaped by geography, climate, and ecological diversity. Ancestral character reconstruction showed shifts in Tb tracked environmental change in the past ∼20,000 years. Thermal preference is 3°C higher than Tb , yet exhibited a lower rate of evolution than Tb and air temperature. Viviparous Liolaemus have lower Tb s than oviparous species, whereas Tp is high for both modes of reproduction, a key difference that results in a thermal buffer for viviparous species to cope with global warming. The rapid increase in environmental temperatures expected in the next 50-80 years in combination with anthropogenic loss of habitats are projected to cause extirpations and extinctions in oviparous species.

The adaptor protein GIPC1 stabilizes the scavenger receptor SR-B1 and increases its cholesterol uptake.

The scavenger receptor class B type 1 (SR-B1), a high-density lipoprotein (HDL) receptor, is a membrane glycoprotein that mediates selective uptake of HDL-cholesterol and cholesterol ester (CE) into cells. SR-B1 is subject to posttranslational regulation; however, the underlying mechanisms still remain obscure. Here, we identified a novel SR-B1-interacting protein, GIPC1 (GAIP-interacting protein, C terminus 1) that interacts with SR-B1 and stabilizes SR-B1 by negative regulation of its proteasomal and lysosomal degradation pathways. The physiological interaction between SR-B1 and GIPC1 was supported by co-immunoprecipitation of wild-type and mutant GIPC1 constructs in SR-B1 ± GIPC1 overexpressing cells, in native liver cells, and in mouse liver tissues. Overexpression of GIPC1 increased endogenous SR-B1 protein levels, subsequently increasing selective HDL-cholesterol/CE uptake and cellular triglyceride (TG) and total cholesterol (TC) levels, whereas silencing of GIPC1 in the mouse liver was associated with blunted hepatic SR-B1 levels, elevated plasma TG and TC, and attenuated hepatic TG and TC content. A positive correlation was identified between GIPC1 and SR-B1 expression, and both expressions of GIPC1 and SR-B1 from human liver samples were inversely correlated with body mass index (BMI) from human subjects. We therefore conclude that GIPC1 plays a key role in the stability and function of SR-B1 and can also effectively regulate hepatic lipid and cholesterol metabolism. These findings expand our knowledge of the regulatory roles of GIPC1 and suggest that GIPC1 exerts a major effect on cell surface receptors such as SR-B1 and its associated hepatic lipid and cholesterol metabolic processes.

Dietary Correlates of Oral and Gut Microbiota in the Water Monitor Lizard, Varanus salvator (Laurenti, 1768).

Numerous studies have demonstrated that food shapes the structure and composition of the host's oral and gut microbiota. The disorder of oral and gut microbiota may trigger various host diseases. Here, we collected oral and gut samples from wild water monitor lizards (Varanus salvator) and their captive conspecifics fed with bullfrogs, eggs, and depilated chicken, aiming to examine dietary correlates of oral and gut microbiota. We used the 16S rRNA gene sequencing technology to analyze the composition of the microbiota. Proteobacteria and Bacteroidota were the dominant phyla in the oral microbiota, and so were in the gut microbiota. The alpha diversity of microbiota was significantly higher in the gut than in the oral cavity, and the alpha diversity of oral microbiota was higher in captive lizards than in wild conspecifics. Comparing the relative abundance of oral and gut bacteria and their gene functions, differences among different animal groups presumably resulted from human contact in artificial breeding environments and complex food processing. Differences in gene function might be related to the absolute number and/or the taxonomic abundance of oral and gut microorganisms in the wild and the water environment. This study provides not only basic information about the oral and gut microbiota of captive and wild water monitor lizards, but also an inference that feeding on frogs and aquatic products and reducing human exposure help water monitor lizards maintain a microbiota similar to that in the wild environment.

The invasive red-eared slider turtle is more successful than the native Chinese three-keeled pond turtle: evidence from the gut microbiota.

BACKGROUND: The mutualistic symbiosis between the gut microbial communities (microbiota) and their host animals has attracted much attention. Many factors potentially affect the gut microbiota, which also varies among host animals. The native Chinese three-keeled pond turtle (Chinemys reevesii) and the invasive red-eared slider turtle (Trachemys scripta elegans) are two common farm-raised species in China, with the latter generally considered a more successful species. However, supporting evidence from the gut microbiota has yet to be collected. METHODS: We collected feces samples from these two turtle species raised in a farm under identical conditions, and analyzed the composition and relative abundance of the gut microbes using bacterial 16S rRNA sequencing on the Roach/454 platform. RESULTS: The gut microbiota was mainly composed of Bacteroidetes and Firmicutes at the phylum level, and Porphyromonadaceae, Bacteroidaceae and Lachnospiraceae at the family level in both species. The relative abundance of the microbes and gene functions in the gut microbiota differed between the two species, whereas alpha or beta diversity did not. Microbes of the families Bacteroidaceae, Clostridiaceae and Lachnospiraceae were comparatively more abundant in C. reevesii, whereas those of the families Porphyromonadaceae and Fusobacteriaceae were comparatively more abundant in T. s. elegans. In both species the gut microbiota had functional roles in enhancing metabolism, genetic information processing and environmental information processing according to the Kyoto Encyclopedia of Genes and Genomes database. The potential to gain mass is greater in T. s. elegans than in C. reevesii, as revealed by the fact that the Firmicutes/Bacteroidetes ratio was lower in the former species. The percentage of human disease-related functional genes was lower in T. s. elegans than in C. reevesii, presumably suggesting an enhanced potential to colonize new habitats in the former species.

Female northern grass lizards judge mates by body shape to reinforce local adaptation.

BACKGROUND: Identifying the factors that contribute to divergence among populations in mate preferences is important for understanding of the manner in which premating reproductive isolation might arise and how this isolation may in turn contribute to the evolutionary process of population divergence. Here, we offered female northern grass lizards (Takydromus septentrionalis) a choice of males between their own population and another four populations to test whether the preferences that females display in the mating trials correlate with phenotypic adaptation to local environments, or to the neutral genetic distance measured by divergence of mitochondrial DNA sequence loci. RESULTS: Females showed a strong preference for native over foreign males. Females that mated with native versus foreign males did not differ from each other in mating latency, or copulation duration. From results of the structural equation modelling we knew that: 1) geographical distance directly contributed to genetic differentiation and environmental dissimilarity; 2) genetic differentiation and environmental dissimilarity indirectly contributed to female mate preference, largely through their effects on morphological divergence; and 3) females judged mates by body shape (appearance) and discriminated more strongly against morphologically less familiar allopatric males. CONCLUSIONS: Local adaptation rather than neutral genetic distance influences female mate preference in T. septentrionalis. The tendency to avoid mating with foreign males may indicate that, in T. septentrionalis, local adaptations are more valuable than genetic novelties. Our results highlight the importance of comprehensive studies integrating ecological, molecular and behavioral approaches to understand population divergence in female mate preferences as the consequence of local adaptations.

Higher temperatures lower rates of physiological and niche evolution.

Understanding rates and patterns of change in physiological and climatic-niche variables is of urgent importance as many species are increasingly threatened by rising global temperatures. Here, we broadly test several fundamental hypotheses about physiological and niche evolution for the first time (with appropriate phylogenetic methods), using published data from 2059 vertebrate species. Our main results show that: (i) physiological tolerances to heat evolve more slowly than those to cold, (ii) the hottest climatic-niche temperatures change more slowly than the coldest climatic-niche temperatures, and (iii) physiological tolerances to heat and cold evolve more slowly than the corresponding climatic-niche variables. Physiological tolerances are significantly and positively related to the corresponding climatic-niche variables, but species often occur in climates outside the range of these tolerances. However, mismatches between climate and physiology do not necessarily mean that the climatic-niche data are misleading. Instead, some standard physiological variables used in vertebrates (i.e. critical thermal maxima and minima) may reflect when species are active (daily, seasonally) and their local-scale microhabitats (sun versus shade), rather than their large-scale climatic distributions.

Captivity affects diversity, abundance, and functional pathways of gut microbiota in the northern grass lizard Takydromus septentrionalis.

Animals in captivity undergo a range of environmental changes from wild animals. An increasing number of studies show that captivity significantly affects the abundance and community structure of gut microbiota. The northern grass lizard (Takydromus septentrionalis) is an extensively studied lacertid lizard and has a distributional range covering the central and southeastern parts of China. Nonetheless, little is known about the gut microbiota of this species, which may play a certain role in nutrient and energy metabolism as well as immune homeostasis. Here, we examined the differences in the gut microbiota between two groups (wild and captive) of lizards through 16S rRNA sequencing using the Illumina HiSeq platform. The results demonstrated that the dominant microbial components in both groups consisted of Proteobacteria, Firmicutes, and Tenericutes. The two groups did not differ in the abundance of these three phyla. Citrobacter was the most dominant genus in wild lizards, while Morganella was the most dominant genus in captive lizards. Moreover, gene function predictions showed that genes at the KEGG pathway levels2 were more abundant in wild lizards than in captive lizards but, at the KEGG pathway levels1, the differences in gene abundances between wild and captive lizards were not significant. In summary, captivity exerted a significant impact on the gut microbial community structure and diversity in T. septentrionalis, and future work could usefully investigate the causes of these changes using a comparative approach.