Lizard Anolis Carolinensis Research Articles

Stable isotopes reveal sex- and context-dependent amino acid routing in green anole lizards (Anolis carolinensis).

Allocation of acquired resources to phenotypic traits is affected by resource availability and current selective context. While differential investment in traits is well documented, the mechanisms driving investment at lower levels of biological organization, which are not directly related to fitness, remain poorly understood. We supplemented adult male and female Anolis carolinensis lizards with an isotopically labelled essential amino acid (13C-leucine) to track routing in four tissues (muscle, liver, gonads, and spleen) under different combinations of resource availability (high and low-calorie diets) and exercise training (sprint training and endurance capacity). We predicted sprint training should drive routing to muscle, and endurance training to liver and spleen, and that investment in gonads should be of lower priority in each of the cases of energetic stress. We found complex interactions between training regime, diet, and tissue type in females, and between tissue type and training and tissue type and diet in males, suggesting that males and females adjust their 13C-leucine routing strategies differently in response to similar environmental challenges. Importantly, our data show evidence of increased 13C-leucine routing in training contexts not to muscle as we expected, but to the spleen, which turns over blood cells, and to the liver, which supports metabolism under differing energetic scenarios. Our results reveal the context-specific nature of long-term tradeoffs associated with increased chronic activity. They also illustrate the importance of considering the costs of locomotion in studies of life history strategies.

Sex-specific effects of immune challenges on green anole lizard metabolism.

Immune responses can increase survival, but they can also incur a variety of costs that may lead to phenotypic trade-offs. The nature of trade-offs between immune activity and other components of the phenotype can vary and depend on the type and magnitude of immune challenge, as well as the energetic costs of simultaneously expressing other traits. There may also be sex-specific differences in both immune activity and trade-offs, particularly with regard to energy expenditure that might differ between males and females during the breeding season. Females are generally expected to invest less in nonspecific immune responses compared to males due to differences in the allocation of resources to reproduction, which may lead to sex differences in the metabolic costs of immunity. We tested for sex-specific differences in metabolic costs of different types of immune challenges in Anolis carolinensis lizards, including lipopolysaccharide (LPS) injection and wounding. We also tested for differences in immune prioritization by measuring bacterial killing ability (BKA). We predicted males would show a greater increase in metabolism after immune challenges, with combined immune challenges eliciting the greatest response. Furthermore, we predicted that metabolic costs would result in decreased BKA. LPS injection increased the resting metabolic rate (RMR) of males but not females. Wounding did not affect RMR of either sex. However, there was an inverse relationship between BKA and wound healing in LPS-injected lizards, suggesting dynamic tradeoffs among metabolism and components of the immune system.

How does mitochondria function contribute to aerobic performance enhancement in lizards?

Aims: Aerobic exercise typically enhances endurance across vertebrates so that chronically high energy demands can be met. Some known mechanisms of doing this include increases in red blood cell numbers, angiogenesis, muscle fiber adaptions, mitochondria biogenesis, and changes to cellular metabolism and oxidative phosphorylation. We used green anole lizards (Anolis carolinensis) to test for an effect of aerobic exercise on metabolism, mitochondria densities, and mitochondrial function. Methods: We first tested the response of green anoles to endurance training and pyrroloquinoline quinone (PQQ) supplementation, which has been shown to increase mitochondria biogenesis. We also conducted a mitochondrial stress test to determine how training affected mitochondrial function in skeletal muscle fibers. Results: Aerobic exercise led to increased endurance and decreased standard metabolic rate (SMR), while PQQ did not affect endurance and increased SMR. In a second experiment, aerobic exercise increased endurance and decreased resting metabolic rate (RMR) in both male and female green anoles. Higher counts of mitochondrial gene copies in trained lizards suggested additional mitochondria adaptations to achieve increased endurance and decreased metabolism. A mitochondrial stress test revealed no effect on baseline oxygen consumption rates of muscle fibers, but untrained lizards had higher maximal oxygen consumption rates with the addition of metabolic fuel. Conclusion: It is likely that trained lizards exhibited lower maximal oxygen consumption rates by developing higher mitochondria efficiency. This adaptation allows for high ATP demand to be met by making more ATP per oxygen molecule consumed. On the other hand, it is possible that untrained lizards prioritized limiting reactive oxygen species (ROS) production at rest, while sacrificing higher levels of proton leak and higher oxygen consumption rates when working to meet high ATP demand.

Rapid introgression of non-native alleles following hybridization between a native Anolis lizard species and acryptic invader across an urban landscape.

Invasive species can impact native populations through competition, predation, habitat alteration, and disease transmission, but also genetically through hybridization. Potential outcomes of hybridization span the continuum from extinction to hybrid speciation and can be further complicated by anthropogenic habitat disturbance. Hybridization between the native green anole lizard (Anolis carolinensis) and a morphologically similar invader (A. porcatus) in south Florida provides an ideal opportunity to study interspecific admixture across a heterogeneous landscape. We used reduced-representation sequencing to describe introgression in this hybrid system and to test for a relationship between urbanization and non-native ancestry. Our findings indicate that hybridization between green anole lineages was probably a limited, historic event, producing a hybrid population characterized by a diverse continuum of ancestry proportions. Genomic cline analyses revealed rapid introgression and disproportionate representation of non-native alleles at many loci and no evidence for reproductive isolation between parental species. Three loci were associated with urban habitat characteristics; urbanization and non-native ancestry were positively correlated, although this relationship did not remain significant when accounting for spatial nonindependence. Ultimately, our study demonstrates the persistence of non-native genetic material even in the absence of ongoing immigration, indicating that selection favouring non-native alleles can override the demographic limitation of low propagule pressure. We also note that not all outcomes of admixture between native and non-native species should be considered intrinsically negative. Hybridization with ecologically robust invaders can lead to adaptive introgression, which may facilitate the long-term survival of native populations otherwise unable to adapt to anthropogenically mediated global change.

The maternal energetic environment affects both egg and offspring phenotypes in green anole lizards (Anolis carolinensis).

Animals exist in dynamic environments that may affect both their own fitness and that of their offspring. Maternal effects might allow mothers to prepare their offspring for the environment in which they will be born via several mechanisms, not all of which are well understood. Resource scarcity and forced resource allocation are two scenarios that could affect maternal investment by altering the amount and type of resources available for investment in offspring, albeit in potentially different ways. We tested the hypothesis that maternal dietary restriction and sprint training have different consequences for the offspring phenotype in an oviparous lizard (Anolis carolinensis). To do this, we collected and reared eggs from adult diet-manipulated females (low-diet [LD] or high-diet [HD]) and sprint-trained females (sprint trained [ST] or untrained [UT]) and measured both egg characteristics and hatchling morphology. ST and LD mothers laid both the fewest and heaviest eggs, and ST, UT, and LD eggs also had significantly longer incubation periods than the HD group. Hatchlings from the diet experiment (LD and HD offspring) were the heaviest overall. Furthermore, both body mass of the mother at oviposition and change in maternal body mass over the course of the experiment had significant and sometimes different effects on egg and offspring phenotypes, highlighting the importance of maternal energetic state to the allocation of maternal resources.

Climate shapes patterns of sexual size and shape dimorphism across the native range of the green anole lizard,Anolis carolinensis(Squamata: Dactyloidae)

AbstractGeographical variation in sexual size dimorphism (SSD) can result from the combined effects of environmental and sexual selection. To understand the determinants of SSD across geographical landscapes, we tested for relationships between SSD and climatic variables in the widespread lizard Anolis carolinensis. To distinguish alternative hypotheses for observed patterns of variation in SSD, we also examined sex-specific patterns of body size evolution and asked whether SSD was associated with certain patterns of sexual shape dimorphism. We found strong evidence for Rensch’s rule (an increase in male-biased SSD with average body size) in A. carolinensis and evidence for the reversed version of Bergmann’s rule (an increase in body size towards warmer environments) in males. Across populations, SSD was positively related to temperature; however, female body size was not related to any climatic variable, suggesting that the latitudinal gradient of SSD might be driven by a gradient in the intensity of sexual selection acting on males. Sexual size dimorphism was positively correlated with sexual dimorphism in head shape and negatively correlated with limb length dimorphism, suggesting that sexual selection in males might drive the evolution of SSD and that differences in size and limb shape between sexes might represent alternative strategies to avoid competition for the same resources.

Endurance training does not affect maximum exertion/distance capacity in Anolis carolinensis lizards.

Locomotor performance abilities are key predictors of survival and reproductive success in animals and understanding how selection targets them can provide insights into how morphology and physiology relate to fitness. But despite the large body of work on performance traits, along with well-established protocols to measure them, performance can be challenging to measure. Endurance, for instance, is commonly measured by recording how long an animal can run at a set pace until exhaustion, which is time consuming and requires dedicated equipment. Consequently, exertion or distance capacity, measured as distance run until exhaustion when chased, is often used as a proxy for endurance, but the relationship between these two metrics has never been assessed even though they likely rely on different underlying physiological mechanisms. We tested experimentally for a relationship between endurance and exertion by training green anole lizards for sprinting and endurance and measuring whether exertion capacity responds to either type of training. Prior to training and across treatments, males displayed a mean (±s.d.) exertion capacity of 14.08±0.29 m and females 12.03±3.52 m; after training, this was 14.78±3.57 m and 12.19±2.21 m, respectively. We found that exertion capacity was unaffected by either type of training in green anoles. We also show that a positive relationship between endurance and exertion capacity pre-training exists only in females and that this relationship is inconsistent among studies. Exertion should be studied as a locomotor trait in its own right and not as a proxy for endurance.

Artificial light at night alters diurnal and nocturnal behavior and physiology in green anole lizards

Artificial light at night (ALAN) disrupts biological rhythms across widely diverse organisms. To determine how energy is allocated by animals in different light environments, we investigated the impacts of ALAN on behavior and physiology of diurnal green anole lizards (Anolis carolinensis). Two groups of 24 adult lizards (half males, half females) were maintained in a controlled lab setting for six weeks. One group was exposed to a simulated natural summer light-dark cycle; the other was exposed to ALAN that simulated urban, nocturnal light exposure. After an acclimation period, we conducted four behavioral trials. One trial examined behavioral time allocation over two 24 h periods, and three others were conducted during mid-day and mid-night: open field tests, to examine exploratory behavior; foraging trials, to examine prey consumption; and social interaction trials, to examine same-sex interactions. We then measured each lizard's snout-vent length and mass of its body, abdominal fat pads, liver, and, for males, testes. Lizards exposed to ALAN were more likely to be awake at night, using nocturnal light to explore, forage, and display to conspecifics. However, during the day, ALAN lizards were less likely to be awake, slower to move, and females displayed less frequently. ALAN lizards had heavier fat pads and testes, but ALAN did not impact body mass, liver mass, or snout-vent length. In sum, ALAN appears to cause a broad shift towards increased nocturnal activity and may alter metabolic and reproductive processes. Future work should examine the fitness consequences of these behavioral and physiological changes.

ECOLOGICAL RELEASE ANALYZED AMONG INDIVIDUALS, ACROSS TWO GENERATIONS, AND ALONG MULTIPLE NICHE AXES IN ANOLIS CAROLINENSIS

A population freed from a constraining interspecific interaction (e.g., competition or predation) may experience niche shifts and expansions. This phenomenon, termed ecological release, is an eco-evolutionary process driven by individual behaviors and interindividual interactions. However, empirical studies of these interactions seldom observe them directly, instead inferring process from pattern. Here, we set up experimental conditions for ecological release of the lizard Anolis carolinensis (green anole) from constraining interactions with its congener, Anolis sagrei (brown anole), by constituting populations of lizards on small islands. We monitored individual and population habitat use along three niche axes (perch height, perch diameter, and lateral movement between perches) on one experimental (one-species) and one control (two-species) island, for three time periods: 1) preremoval, when both islands had both species; 2) postremoval, shortly after A. sagrei were cleared from the experimental island; and 3) delayed postremoval, 7 months later, when long-lived lizards were joined by a second generation born in the intervening months. We found that green anole perch height decreased on the one-species island and increased on the two-species island. These shifts did not occur during postremoval but were evident by delayed postremoval, when both generations on the one-species island were perching nearly 130 cm lower than their counterparts on the two-species island. We also documented correlated changes in perch diameter at both the individual and population level but no changes in the extent of individuals' lateral movement. Lastly, changes in population-level niche width (i.e., perch height and diameter variances) occurred without detectable changes in niche overlap among individuals. Our results demonstrate that that the dynamics of ecological release in nature need not be inferred, because experiments can observe them directly in individuals, across generations, and along multiple niche axes.

Lizard Blastema Organoid Model Recapitulates Regenerated Tail Chondrogenesis.

(1) Background: Lizard tail regeneration provides a unique model of blastema-based tissue regeneration for large-scale appendage replacement in amniotes. Green anole lizard (Anolis carolinensis) blastemas contain fibroblastic connective tissue cells (FCTCs), which respond to hedgehog signaling to create cartilage in vivo. However, an in vitro model of the blastema has not previously been achieved in culture. (2) Methods: By testing two adapted tissue dissociation protocols and two optimized media formulations, lizard tail FCTCs were pelleted in vitro and grown in a micromass blastema organoid culture. Pellets were analyzed by histology and in situ hybridization for FCTC and cartilage markers alongside staged original and regenerating lizard tails. (3) Results: Using an optimized serum-free media and a trypsin- and collagenase II-based dissociation protocol, micromass blastema organoids were formed. Organoid cultures expressed FCTC marker CDH11 and produced cartilage in response to hedgehog signaling in vitro, mimicking in vivo blastema and tail regeneration. (4) Conclusions: Lizard tail blastema regeneration can be modeled in vitro using micromass organoid culture, recapitulating in vivo FCTC marker expression patterns and chondrogenic potential.

Aggressive but not reproductive boldness in male green anole lizards correlates with baseline vasopressin activity

Across species, individuals within a population differ in their level of boldness in social encounters with conspecifics. This boldness phenotype is often stable across both time and social context (e.g., reproductive versus agonistic encounters). Various neural and hormonal mechanisms have been suggested as underlying these stable phenotypic differences, which are often also described as syndromes, personalities, and coping styles. Most studies examining the neuroendocrine mechanisms associated with boldness examine subjects after they have engaged in a social interaction, whereas baseline neural activity that may predispose behavioral variation is understudied. The present study tests the hypotheses that physical characteristics, steroid hormone levels, and baseline variation in Ile3-vasopressin (VP, a.k.a., Arg8-vasotocin) signaling predispose boldness during social encounters. Boldness in agonistic and reproductive contexts was extensively quantified in male green anole lizards (Anolis carolinensis), an established research organism for social behavior research that provides a crucial comparison group to investigations of birds and mammals. We found high stability of boldness across time, and between agonistic and reproductive contexts. Next, immunofluorescence was used to colocalize VP neurons with phosphorylated ribosomal protein S6 (pS6), a proxy marker of neural activity. Vasopressin-pS6 colocalization within the paraventricular and supraoptic nuclei of the hypothalamus was inversely correlated with boldness of aggressive behaviors, but not of reproductive behaviors. Our findings suggest that baseline vasopressin release, rather than solely context-dependent release, plays a role in predisposing individuals toward stable levels of displayed aggression toward conspecifics by inhibiting behavioral output in these contexts.

Characterizing seasonal transitions: Breeding-like morphology and behavior during the late non-breeding season in green anole lizards

Seasonally breeding animals, such as green anole lizards (Anolis carolinensis), allow for the examination of the control of reproduction during different reproductive states. During the breeding season, the gonads are large and reproductively active. Following the breeding season, gonads regress and become less active, and the lizards enter a refractory period where breeding is inhibited. After this stage, a post-refractory period occurs during which the lizards are still in a non-breeding state, but environmental changes can trigger the onset of breeding. However, it is unclear what causes these changes in reproductive state and we hypothesized that this may be due to alterations in gonadotropin-releasing hormone (GnRH) signaling. The present study aimed to identify morphological and behavioral differences in GnRH- and saline-injected refractory and post-refractory male anoles when housed under the same non-breeding environmental conditions. We found that post-refractory anoles had increased testicular weight, recrudescence, sperm presence, and reproductive behavior, with no impact of GnRH injection. Renal sex segment size and steroidogenic acute regulatory protein (StAR) mRNA levels did not differ among groups, indicating that testosterone levels likely had not increased in post-refractory lizards. Post-refractory anoles in this study were beginning to transition towards a breeding state without exposure to changing environmental conditions, and GnRH was not necessary for these changes. These data reveal a complex interaction between the activation of breeding, changing environmental conditions, and the underlying physiology regulating reproduction in seasonally breeding lizards. Future studies are needed to further elucidate the mechanisms that regulate this relationship.

Immunolocalization of the EDWM-Protein Indicates a Matrix Role in Cornification of Lizard Epidermis

During epidermal differentiation in the scales of lizards and snakes, from the basal layer beta- and later alpha-keratinocytes are generated to form beta-and alpha-corneous layers. In the lizard Anolis carolinensis, minor proteins derived from the EDC (Epidermal Differentiation Complex) are added to the main constituent proteins, IFKs (Intermediate Filament Keratins) and CBPs (Corneous Beta Proteins, formerly indicated as beta keratins). One of these proteins that previous studies showed to be exclusively expressed in the skin, EDWM (EDC protein containing high GSRC amino acids) is rich in cysteine and arginine, amino acids that form numerous –S–S– and electro-static chemical bonds in the corneous material. Light and electron microscopy immunolbeling for EDWM show a diffuse localization in differentiating beta-cells and in some alpha-cells, in particular those of the clear-layer, involved in epidermal shedding. The study suggests that EDWM may function as a matrix protein that binds to IFKs and CBPs, contributing to the formation of the specific corneous material present in beta- and alpha-corneous layers. In particular, its higher immunolocalization in the maturing clear layer indicates that this protein is important for its differentiation and epidermal shedding in A. carolinensis and likely also in other lepidosaurian reptiles.

Social boldness correlates with brain gene expression in male green anoles

Within populations, some individuals tend to exhibit a bold or shy social behavior phenotype relative to the mean. The neural underpinnings of these differing phenotypes – also described as syndromes, personalities, and coping styles – is an area of ongoing investigation. Although a social decision-making network has been described across vertebrate taxa, most studies examining activity within this network do so in relation to exhibited differences in behavioral expression. Our study instead focuses on constitutive gene expression in bold and shy individuals by isolating baseline gene expression profiles that influence social boldness predisposition, rather than those reflecting the results of social interaction and behavioral execution. We performed this study on male green anole lizards (Anolis carolinensis), an established model organism for behavioral research, which provides a crucial comparison group to investigations of birds and mammals. After identifying subjects as bold or shy through repeated reproductive and agonistic behavior testing, we used RNA sequencing to compare gene expression profiles between these groups within various forebrain, midbrain, and hindbrain regions. The ventromedial hypothalamus had the largest group differences in gene expression, with bold males having increased expression of neuroendocrine and neurotransmitter receptor and calcium channel genes compared to shy males. Conversely, shy males express more integrin alpha-10 in the majority of examined regions. There were no significant group differences in physiology or hormone levels. Our results highlight the ventromedial hypothalamus as an important center of behavioral differences across individuals and provide novel candidates for investigations into the regulation of individual variation in social behavior phenotype.

The Effect of Long Term Captivity on Stress Levels in Anolis carolinensis Lizards

ABSTRACT The effect of long term captivity is a factor that is important for all research utilizing wild caught animals. Despite the fact that it can be considered to be one of the most fundamental potential sources of stress in captivity, it has received a low amount of interest in recent research on lizards. Given the wide variety in ecology and life history among lizards species, it would make sense to investigate the effect of long term captivity on wild caught lizards on a broader scale. In this study we investigated the effect of long term captivity (four months) on the physiology and behavior of male and female Anolis carolinensis lizards. Our results showed no negative effects of four months of captivity on physiological and behavioral measurements in male A carolinensis lizards. Similar results for females were found for all measurements except body mass and tail width. Here our results indicated a potential negative effect of four months of captivity on body mass and tail width in females.

Immune activation affects whole-organism performance in male but not female green anole lizards (Anolis carolinensis).

Immune responses are intuitively beneficial, but they can incur a variety of costs, many of which are poorly understood. The nature and extent of trade-offs between immune activity and other components of the integrated phenotype can vary, and depend on the type of immune challenge, as well as the energetic costs of simultaneously expressing other traits. There may also be sex differences in both immune activity and immunity-induced trade-offs, particularly in the case of trade-offs involving functional traits such as whole-organism performance capacities that might be of different fitness value to males and females. We tested the response of three performance traits (sprinting, endurance, and biting) to two different immune challenges (LPS injection and wound healing) in both male and female Anolis carolinensis lizards. We found clear differences in how male and female performance capacities were affected by immune activation. LPS injection and wound healing had interactive effects on all three performance traits in males, but immune activation did not affect female performance. We also found that the degree of wound healing exhibited complex interactive effects involving sex and type of immune activation that varied depending on the performance trait in question. These results demonstrate that male and female green anoles experience different consequences of immune responses, and also that the type and extent of that activation can drive trait-specific performance trade-offs.

Heat hardening in a pair of Anolis lizards: constraints, dynamics and ecological consequences.

Heat tolerance plasticity is predicted to be an important buffer against global warming. Nonetheless, basal heat tolerance often correlates negatively with tolerance plasticity ('trade-off hypothesis'), a constraint that could limit plasticity benefits. We tested the trade-off hypothesis at the individual level with respect to heat hardening in two lizard species, Anolis carolinensis and Anolis sagrei. Heat hardening is a rapid increase in heat tolerance after heat shock that is rarely measured in reptiles but is generally considered to be a first line of physiological defense against heat. We also employed a biophysical model of operative habitat temperatures to estimate the performance consequences of hardening under ecologically relevant conditions. Anolis carolinensis hardened by 2h post-heat shock and maintained hardening for several hours. However, A. sagrei did not harden. Biophysical models showed that hardening in A. carolinensis reduces their overheating risk in the field. Therefore, while not all lizards heat harden, hardening has benefits for species that can. We initially found a negative relationship between basal tolerance and hardening within both species, consistent with the trade-off hypothesis. However, permutation analyses showed that the apparent trade-offs could not be differentiated from statistical artifact. We found the same result when we re-analyzed published data supporting the trade-off hypothesis in another lizard species. Our results show that false positives may be common when testing the trade-off hypothesis. Statistical approaches that account for this are critical to ensure that the hypothesis, which has broad implications for thermal adaptation and responses to warming, is assessed appropriately.

Neural and endocrine responses to social stress differ during actual and virtual aggressive interactions or physiological sign stimuli

Neural and endocrine responses provide quantitative measures that can be used for discriminating behavioral output analyses. Experimental design differences often make it difficult to compare results with respect to the mechanisms producing behavioral actions. We hypothesize that comparisons of distinctive behavioral paradigms or modification of social signals can aid in teasing apart the subtle differences in animal responses to social stress. Eyespots are a unique sympathetically activated sign stimulus of the lizard Anolis carolinensis that influence aggression and social dominance. Eyespot formation along with measurements of central and plasma monoamines enable comparison of paired male aggressive interactions with those provoked by a mirror image. The results suggest that experiments employing artificial application of sign stimuli in dyadic interactions amplify behavioral, neural and endocrine responses, and foreshorten behavioral interactions compared to those that develop among pairs naturally. While the use of mirrors to induce aggressive behavior produces simulated interactions that appear normal, some behavioral, neural, and endocrine responses are amplified in these experiments as well. In contrast, mirror image interactions also limit the level of certain behavioral and neuroendocrine responses. As true social communication does not occur during interaction with mirror images, rank relationships can never be established. Multiple experimental approaches, such as combining naturalistic social interactions with virtual exchanges and/or manipulation of sign stimuli, can often provide added depth to understanding the motivation, context, and mechanisms that produce specific behaviors. The addition of endocrine and neural measurements helps identify the contributions of specific behavioral elements to the social processes proceeding.

Arginine vasotocin impacts chemosensory behavior during social interactions of Anolis carolinensis lizards

In reptiles, arginine vasotocin (AVT) impacts the performance of and response to visual social signals, but whether AVT also operates within the chemosensory system as arginine vasopressin (AVP) does in mammals is unknown, despite social odors being potent modifiers of competitive and appetitive behavior in reptiles. Here, we ask whether elevated levels of exogenous AVT impact rates of chemical display behavior (e.g. tongue flicks) in adult males, and whether conspecific males or females can chemically discriminate between competitor males based on differing levels of exogenous AVT in green anoles (Anolis carolinensis). We injected wild-caught green anole males with either AVT (AVT-Males) or a vehicle control (CON-Males) solution, then presented treated males with a conspecific stimulus (Intruder-Male or Intruder-Female) and filmed 30-minute interactions. We found that AVT-Males were faster than CON-Males to perform a tongue flick to conspecifics, and faster to chemically display toward Intruder-Females, suggesting AVT increased male interest in available chemical information during social encounters. Intruders performed more lip smack behavior when interacting with AVT-Males than with CON-Males, and Intruder-Males performed more tongue flick behavior when interacting with AVT-Males than with CON-Males, suggesting anoles can discriminate between conspecifics based on exogenous AVT levels. We also found a reduction in Intruder movement behavior when Intruders were paired with AVT-Males. This study provides empirical support for AVT-mediated chemosensory behavior in reptilian social interactions, in a microsmatic lizard species, suggesting the mechanism by which mammalian AVP and non-mammalian AVT mediate chemosensory behavior during social interactions may be evolutionarily conserved.

Post-hurricane shifts in the morphology of island lizards

AbstractHurricanes are expected to increase in both frequency and intensity as a result of climate change, but the impacts of these disturbances on the evolutionary trajectories of the species they affect are not yet well understood. In this project, we investigated population-level changes in morphology in the lizard Anolis carolinensis after Hurricane Irma in 2017. We found that anole populations were morphologically distinct after the hurricane, exhibiting significantly longer forelimbs and hindlimbs compared with pre-hurricane measurements. These morphological changes were consistent across two replicate islands and between males and females. The observed morphological shifts were potentially driven by positive selection from Hurricane Irma on clinging capacity. In this opportunistic study, we documented post-hurricane changes in the morphology of island lizards and suggest the potential for increasingly frequent and intense hurricanes to play an important role in natural selection and anole evolution.