| transcriptome sequencing reveals signatures of positive selection in the spot-tailed earless lizard. | the continual loss of threatened biodiversity is occurring at an accelerated pace. high-throughput sequencing technologies are now providing opportunities to address this issue by aiding in the generation of molecular data for many understudied species of high conservation interest. our overall goal of this study was to begin building the genomic resources to continue investigations and conservation of the spot-tailed earless lizard. here we leverage the power of high-throughput sequencing to ge ... | 2020 | 32542006 |
| plastic sexual ornaments: assessing temperature effects on color metrics in a color-changing reptile. | conspicuous coloration is an important subject in social communication and animal behavior, and it can provide valuable insight into the role of visual signals in social selection. however, animal coloration can be plastic and affected by abiotic factors such as temperature, making its quantification problematic. in such cases, careful consideration is required so that metric choices are consistent across environments and least sensitive to abiotic factors. a detailed assessment of plastic trait ... | 2020 | 32433700 |
| endocrine stress response of eastern fence lizards in fire-disturbed landscapes. | landscape disturbances can alter habitat structure and resource availability, often inducing physiological responses by organisms to cope with the changing conditions. quantifying the endocrine stress response through measurement of glucocorticoids has become an increasingly common method for determining how organisms physiologically respond to challenges imposed by their environment. we tested the hypothesis that eastern fence lizards cope with fire disturbance effects by modulating their secre ... | 2019 | 31857811 |
| obtaining plasma to measure baseline corticosterone concentrations in reptiles: how quick is quick enough? | there is growing interest in the use of glucocorticoid (gc) hormones to understand how wild animals respond to environmental challenges. blood is the best medium for obtaining information about recent gc levels; however, obtaining blood requires restraint and can therefore be stressful and affect gc levels. there is a delay in gcs entering blood, and it is assumed that blood obtained within 3 min of first disturbing an animal reflects a baseline level of gcs, based largely on studies of birds an ... | 2020 | 31733208 |
| gestation alters the gut microbiota of an oviparous lizard. | mammalian pregnancy can alter the diversity, membership and structure of the maternal gut microbiota, but it is unclear whether this phenomenon occurs in vertebrates with different reproductive strategies. we conducted 16s rrna bacterial inventories to investigate whether oviparous lizards exhibit shifts in gut microbiota similar to those observed in mammals. using wild-caught eastern fence lizards from alabama, usa, we collected and extracted fecal dna from gravid and non-gravid individuals ove ... | 2019 | 31210275 |
| contrasting responses of lizards to divergent ecological stressors across biological levels of organization. | it is frequently hypothesized that animals employ a generalized "stress response," largely mediated by glucocorticoid (gc) hormones, such as corticosterone, to combat challenging environmental conditions. under this hypothesis, diverse stressors are predicted to have concordant effects across biological levels of an organism. we tested the generalized stress response hypothesis in two complementary experiments with juvenile and adult male eastern fence lizards (sceloporus undulatus). in both exp ... | 2019 | 31127305 |
| maternal corticosterone increases thermal sensitivity of heart rate in lizard embryos. | while it is well established that maternal stress hormones, such as corticosterone (cort), can induce transgenerational phenotypic plasticity, few studies have addressed the influence of maternal cort on pre-natal life stages. we tested the hypothesis that experimentally increased cort levels of gravid female eastern fence lizards ( sceloporus undulatus) would alter within-egg embryonic phenotype, particularly heart rates. we found that embryos from cort-treated mothers had heart rates that incr ... | 2019 | 30958207 |
| glucocorticoids do not influence a secondary sexual trait or its behavioral expression in eastern fence lizards. | secondary sexual traits and associated behaviors can be influenced by environmental factors such as exposure to stressors. such effects may be mediated by the physiological stress response, which is typified by the release of glucocorticoid hormones. the effects of glucocorticoids on sexual traits such as plumage and display coloration have most commonly been studied in isolation rather than in conjunction with other pertinent aspects of signalling, such as behavior and habitat use, though these ... | 2019 | 30914721 |
| population history with invasive predators predicts innate immune function response to early-life glucocorticoid exposure in lizards. | early-life stress can suppress immune function, but it is unclear whether transgenerational stress exposure modulates the immune consequences of early stress. in populations where, historically, the immune system is frequently activated, e.g. persistent stressors that cause injury, it may be maladaptive to suppress immune function after early-life stress. thus, the relationship between early-life stress and immune function may vary with population-level historical stressor exposure. we collected ... | 2019 | 30659082 |
| presence of an invasive species reverses latitudinal clines of multiple traits in a native species. | understanding the processes driving formation and maintenance of latitudinal clines has become increasingly important in light of accelerating global change. many studies have focused on the role of abiotic factors, especially temperature, in generating clines, but biotic factors, including the introduction of non-native species, may also drive clinal variation. we assessed the impact of invasion by predatory fire ants on latitudinal clines in multiple fitness-relevant traits-morphology, physiol ... | 2019 | 30488524 |
| morphological features of the yolk processing pattern in the eastern fence lizard, sceloporus undulatus (phrynosomatidae). | features of embryonic development in birds traditionally have been assumed to be shared by sauropsids in general. herein, we document a pattern of yolk processing and cellularization in the eastern fence lizard (sceloporus undulatus) that is fundamentally different from that of birds. in the avian pattern, cells of the yolk sac lining phagocytose, and digest yolk material. these cells release products of digestion into underlying blood vessels for transport back to the embryo. in contrast, micro ... | 2018 | 30350360 |
| maternal stress alters the phenotype of the mother, her eggs and her offspring in a wild-caught lizard. | while biomedical researchers have long appreciated the influence of maternally derived glucocorticoids (gcs) on offspring phenotype, ecologists have only recently begun exploring its impact in wild animals. interpreting biomedical findings within an ecological context has posited that maternal stress, mediated by elevations of maternal gcs, may play an adaptive role preparing offspring for a stressful or rigorous environment. yet, the influence of maternal stress on offspring phenotype has been ... | 2018 | 30074248 |
| survival and reproductive costs of repeated acute glucocorticoid elevations in a captive, wild animal. | organisms are continuously encountering both predictable and unpredictable ecological stressors within their environment. the activation of the hypothalamic-pituitaryadrenal (stress) axis is a fundamental process allowing animals to cope with and respond to such encounters. a main consequence of hpa axis activation is the release of glucocorticoid hormones. although short-term glucocorticoid elevations lead to changes in physiological and behavioral processes that are often adaptive, our underst ... | 2018 | 30016628 |
| sex-dependent effects of maternal stress: stressed moms invest less in sons than daughters. | multigenerational effects can have important and sex-dependent effects on offspring. sex allocation theory predicts that females should differentially invest in sons and daughters depending on sex-specific fitness returns and costs of investment. maternal stress-relevant (glucocorticoid) hormones may be one mechanism driving this effect. we investigated how maternal stress hormones differentially affected sons and daughters by manipulating levels of the glucocorticoid, corticosterone (cort), in ... | 2018 | 29992777 |
| epigenetic response to environmental change: dna methylation varies with invasion status. | epigenetic mechanisms may be important for a native species' response to rapid environmental change. red imported fire ants (solenopsis invicta santschi, 1916) were recently introduced to areas occupied by the eastern fence lizard (sceloporus undulatus bosc & daudin, 1801). behavioral, morphological and physiological phenotypes of the eastern fence lizard have changed following invasion, creating a natural biological system to investigate environmentally induced epigenetic changes. we tested for ... | 2016 | 29492288 |
| bergmann's clines in ectotherms: illustrating a life-history perspective with sceloporine lizards. | the generality and causes of bergmann's rule have been debated vigorously in the last few years, but bergmann's clines are rarely explained in the context of life-history theory. we used both traditional and phylogenetic comparative analyses to explore the causes of latitudinal and thermal clines in the body size of the eastern fence lizard (sceloporus undulatus). the proximate mechanism for larger body sizes in colder environments is delayed maturation, which results in a greater fecundity but ... | 2004 | 29641924 |