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1.
PLoS One ; 15(1): e0228043, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31978205

RESUMO

This study aims to analyze the thermal biology and climatic vulnerability of two closely related lizard species (Stenocercus festae and S. guentheri) inhabiting the Ecuadorian Andes at high altitudes. Four physiological parameters-body temperature (Tb), preferred temperature (Tpref), critical thermal maximum (CTmax), and critical thermal minimum (CTmin)-were evaluated to analyze the variation of thermophysiological traits among these populations that inhabit different environmental and altitudinal conditions. We also evaluate the availability of operative temperatures, warming tolerance, and thermal safety margin of each population to estimate their possible risks in the face of future raising temperatures. Similar to previous studies, our results suggest that some physiological traits (CTmax and Tb) are influenced by environmental heterogeneity, which brings changes on the thermoregulatory behavior. Other parameters (Tpref and CTmin), may be also influenced by phylogenetic constraints. Moreover, the fluctuating air temperature (Tair) as well as the operative temperatures (Te) showed that these lizards exploit a variety of thermal microenvironments, which may facilitate behavioral thermoregulation. Warming tolerance and thermal safety margin analyses suggest that both species find thermal refugia and remain active without reducing their performance or undergoing thermal stress within their habitats. We suggest that studies on the thermal biology of tropical Andean lizards living at high altitudes are extremely important as these environments exhibit a unique diversity of microclimates, which consequently result on particular thermophysiological adaptations.


Assuntos
Mudança Climática , Lagartos/fisiologia , Temperatura , Clima Tropical , Adaptação Fisiológica , Ar , Animais , Equador
2.
PLoS One ; 15(1): e0226913, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31945104

RESUMO

INTRODUCTION: Fundamental data on the distributions, diversity, and threat status of terrestrial snakes and lizards (hereafter squamates) is limited. This is due to the cryptic nature of species in this faunal group, and to limitations in the effectiveness of the survey methods used to detect these species. Camera-traps are a useful tool for detecting numerous vertebrate species, yet their use for detecting squamates has been limited. Here, we apply recent methodological advancements in camera-trapping and assessed the utility of camera-traps for inventorying a squamate assemblage by comparing camera-trapping survey results with two widely used labour-intensive methods: artificial refuges and pitfall traps. METHODS: We conducted a 74-day survey using camera-traps and, concurrently, four by four-day surveys using labour-intensive methods. Given the duration and three detection methods, we compared seven variants of survey protocol, including using each method alone or all methods simultaneously. We compared both the effectiveness and cost-effectiveness of each survey protocol by estimating the number of species detected at the transect level, and by calculating the costs of conducting those surveys. RESULTS: We found the camera-trapping survey was most cost-effective, costing 687 AUD (CI 534-912) per squamate species detected, compared with the 2975 AUD (CI 2103-4486) per squamate species detected with the labour-intensive methods. Using all methods together was less cost-effective than using camera-traps alone. Additionally, there was a 99% probability that camera-traps would detect more species per transect than the labour-intensive methods examined. DISCUSSION & CONCLUSION: By focusing the analysis at the level of the survey, rather than the level of the device, camera-traps are both a more effective and cost-effective technique for surveying terrestrial squamates. Where circumstances are appropriate, those wildlife researchers and managers currently using camera-traps for non-squamate surveys, can adopt the methods presented to incorporate squamate surveys with little upfront cost. Additionally, researchers currently using traditional techniques can be confident that switching to camera-traps will likely yield improved results. Still, camera-traps are not a panacea and careful consideration into the benefits and usefulness of these techniques in individual circumstances is required.


Assuntos
Lagartos/fisiologia , Serpentes/fisiologia , Gravação em Vídeo/economia , Animais , Conservação dos Recursos Naturais/métodos , Análise Custo-Benefício , Demografia , Inquéritos e Questionários
3.
Gen Comp Endocrinol ; 285: 113288, 2020 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-31557468

RESUMO

Chronic stressors have profound impacts on phenotypes and life history strategies on the short term, but delayed effects of stress experienced late in life remain poorly investigated in wild populations. Here, we used a combined laboratory and field experiment to test if chronic stress late in life has immediate and delayed effects on physiological and demographic traits in the common lizard, Zootoca vivipara. We increased plasma corticosterone levels in adults and yearlings during three weeks of the post-reproductive season. We quantified immediate responses in the laboratory, delayed intra-generational effects in field enclosures one month and one year later during the next reproductive season, and delayed inter-generational effects in the first generation of offspring. Our phenotypic assays included metabolism, immune capacities, lipid metabolism and oxidative stress. Relative to placebos, lizards treated with corticosterone had higher body condition and lower oxidative damages but an increased skin swelling response directly after the manipulation. Delayed responses in field enclosures were of three types. First, we found catch-up growth for body mass such the placebos had similar body conditions one month after the laboratory manipulation. Second, we found persistent differences in oxidative damages during one month but not one year later. Third, during the next reproductive season, corticosterone-treated females had higher levels of plasma triglycerides, whereas corticosterone-treated individuals had a higher skin swelling response. We found no delayed inter-generational effects on demographic traits of offspring. Our study demonstrates the potential for long-lasting physiological consequences of chronic corticosterone enhancement despite no obvious changes in life history.


Assuntos
Glucocorticoides/metabolismo , Estágios do Ciclo de Vida , Lagartos/fisiologia , Animais , Antioxidantes/metabolismo , Corticosterona/metabolismo , Feminino , Masculino , Tamanho da Amostra , Estresse Fisiológico/efeitos dos fármacos
4.
Gen Comp Endocrinol ; 285: 113295, 2020 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-31580883

RESUMO

Life history transitions and hormones are known to interact and influence many aspects of animal physiology and behavior. The South-American tegu lizard (Salvator merianae) exhibits a profound seasonal shift in metabolism and body temperature, characterized by high daily activity during warmer months, including reproductive endothermy in spring, and metabolic suppression during hibernation in winter. This makes S. merianae an interesting subject for studies of interrelationships between endocrinology and seasonal changes in physiology/behavior. We investigated how plasma concentrations of hormones involved in regulation of energy metabolism (thyroid hormones T4 and T3; corticosterone) and reproduction (testosterone in males and estrogen/progesterone in females) correlate with activity and body temperature (Tb) across the annual cycle of captive held S. merianae in semi-natural conditions. In our initial model, thyroid hormones and corticosterone showed a positive relationship with activity and Tb with independent of sex: T3 positively correlated with activity and Tb, while T4 and corticosterone correlated positively with changes in Tb only. This suggests that thyroid hormones and glucocorticoids may be involved in metabolic transitions of annual cycle events. When accounting for sex-steroid hormones, our sex separated models showed a positive relationship between testosterone and Tb in males and progesterone and activity in females. Coupling seasonal endocrine measures with activity and Tb may expand our understanding of the relationship between animal's physiology and its environment. Manipulative experiments are required in order to unveil the directionality of influences existing among abiotic factors and the hormonal signaling of annual cyclicity in physiology/behavior.


Assuntos
Temperatura Corporal , Hormônios/metabolismo , Lagartos/fisiologia , Animais , Corticosterona/sangue , Sistema Endócrino/metabolismo , Metabolismo Energético , Feminino , Glucocorticoides/metabolismo , Masculino , Progesterona/metabolismo , Estações do Ano , Testosterona/metabolismo , Hormônios Tireóideos/metabolismo
5.
PLoS One ; 14(12): e0226399, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31856183

RESUMO

Alterations in thermal niches have been widely associated with the Anthropocene erosion of reptiles' diversity. They entail potential physiological constraints for organisms' performance, which can lead to activity restrictions and impact fitness and demography. Reptiles are ectotherms which rely on seasonal periodicity to maximize the performance of biological functions. Despite it, the ecological implications of shifts in local temperatures are barely explored at the seasonal scale. This study aims to assess how changes in air temperature and substrate temperature affect the activity, body temperature (Tb) and thermoregulation patterns of the sand lizard, Liolaemus arambarensis (an endangered, microendemic species from southern Brazil), throughout a four-year period. Field surveys were conducted monthly on a restricted population in a sand-dune habitat. The annual fluctuations of the seasonal temperatures led to significant changes in the activity and Tb of L. arambarensis and shaped thermoregulation trends, suggesting biological plasticity as a key factor in the face of such variability. Lizards tended to maintain seasonal Tb in mild and harsh seasons through increased warming/cooling efforts. Anomalous winter conditions seemed especially critical for individual performance due to their apparent high impact favouring/constraining activity. Activity and thermoregulation were inhibited in frigid winters, probably due to a vulnerable physiology to intense cold spells determined by higher preferred body temperatures than Tb. Our results warn of a complex sensitivity in lizards to anomalous seasonal temperatures, which are potentially enhanced by climate change. The current work highlights the importance of multiannual biomonitoring to disentangle long-term responses in the thermal biology of reptiles and, thereby, to integrate conservation needs in the scope of global change.


Assuntos
Regulação da Temperatura Corporal , Lagartos/fisiologia , Estações do Ano , Temperatura , Clima Tropical , Animais , Fatores de Tempo
6.
PLoS One ; 14(12): e0226949, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31881075

RESUMO

Morphological convergence is an intensely studied macroevolutionary phenomenon. It refers to the morphological resemblance between phylogenetically distant taxa. Currently available methods to explore evolutionary convergence either: rely on the analysis of the phenotypic resemblance between sister clades as compared to their ancestor, fit different evolutionary regimes to different parts of the tree to see whether the same regime explains phenotypic evolution in phylogenetically distant clades, or assess deviations from the congruence between phylogenetic and phenotypic distances. We introduce a new test for morphological convergence working directly with non-ultrametric (i.e. paleontological) as well as ultrametric phylogenies and multivariate data. The method (developed as the function search.conv within the R package RRphylo) tests whether unrelated clades are morphologically more similar to each other than expected by their phylogenetic distance. It additionally permits using known phenotypes as the most recent common ancestors of clades, taking full advantage of fossil information. We assessed the power of search.conv and the incidence of false positives by means of simulations, and then applied it to three well-known and long-discussed cases of (purported) morphological convergence: the evolution of grazing adaptation in the mandible of ungulates with high-crowned molars, the evolution of mandibular shape in sabertooth cats, and the evolution of discrete ecomorphs among anoles of Caribbean islands. The search.conv method was found to be powerful, correctly identifying simulated cases of convergent morphological evolution in 95% of the cases. Type I error rate is as low as 4-6%. We found search.conv is some three orders of magnitude faster than a competing method for testing convergence.


Assuntos
Evolução Biológica , Algoritmos , Animais , Gatos/anatomia & histologia , Gatos/genética , Gatos/fisiologia , Fósseis , Lagartos/anatomia & histologia , Lagartos/genética , Lagartos/fisiologia , Mandíbula/anatomia & histologia , Mandíbula/fisiologia , Fenótipo , Filogenia , Índias Ocidentais
7.
An Acad Bras Cienc ; 91(4): e20190055, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31778459

RESUMO

The immune state is an essential component of survival as it directly influences physiological performance and health status. Variation in the leukocyte profile, a significantly increase in body temperature, and a detriment of the eco-physiological performance are among the possible consequences of an unhealthy state. In this study we analyse and discuss how field body temperature, preferred body temperature, the speed for sprint and long runs, locomotor stamina, and body condition can be affected by the immunological state (i.e. leukocyte profile) in a wild population of Liolaemus sarmentoi. Juveniles and adult males with a high percentage of eosinophils, basophils, and a low percentage of monocytes preferred higher body temperatures in a thermal gradient, while pregnant females maintained thermal preferences independently of leukocyte profile. Although juveniles with a high percentage of heterophils showed less locomotor stamina, adult males and pregnant females showed no differences in locomotor performance in relation to leukocyte profile. This study represents a starting point in eco-immunology of a wild lizard population of Liolaemus in cold and temperate environments of Patagonia where the southward shift in the geographic ranges of pathogen populations due to global warming represents a threat to resident host populations.


Assuntos
Comportamento Animal/fisiologia , Temperatura Corporal/imunologia , Lagartos/sangue , Lagartos/imunologia , Atividade Motora/imunologia , Aclimatação , Animais , Temperatura Corporal/fisiologia , Feminino , Lagartos/fisiologia , Masculino , Atividade Motora/fisiologia , Gravidez
8.
C R Biol ; 342(9-10): 299-308, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31734081

RESUMO

The Heat Shock Proteins (HSPs) are a superfamily of molecular chaperones that maintain cellular homeostasis under stress. HSP70 represents the major stress-inducible family member, often activated in response to changes in thermal ranges of organisms, and therefore playing an important role enhancing thermal tolerance limits in ectothermic animals. The present study aimed to investigate the presence and the localization of HSP70 through the development of Podarcis siculus, an oviparous lizard inhabiting temperate Mediterranean regions, showing a limited potential to tolerate thermal changes during embryogenesis. Immunohistochemical analysis demonstrated that HSP70 protein is constitutively present in early embryonic stages, abundantly distributed in eye, in encephalic domains (predominantly in ventricular areas and in grey matter), in grey matter of spinal cord, in lung, gut mucosa, hepatic cords and kidney tubules. Interestingly, a severe drop in incubation temperature (5°C for 3 days) does not induce enhancements in HSP70 levels nor changes in tissues localization. These results suggest that the HSP70 found in P. siculus embryos represents a non-inducible, constitutive molecular chaperone that should be better called Heat Shock Cognate 70 (HSC70); the presence of stress-induced members of the HSP family in P. siculus has yet to be proven.


Assuntos
Resposta ao Choque Frio/fisiologia , Proteínas de Choque Térmico HSP70/metabolismo , Lagartos/fisiologia , Animais , Desenvolvimento Embrionário/fisiologia , Temperatura Alta , Temperatura
9.
Naturwissenschaften ; 106(9-10): 55, 2019 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-31612286

RESUMO

Sexual signals serve as an honest indicator of individual quality, reflecting either developmental and/or maintenance costs. A possible underlying physiological mechanism is oxidative stress, which could mediate energy trade-offs between sexual signals and other quality traits. In ectotherms, thermal performance acts as a key indicator of individual quality and influence signal intensity. We investigated how oxidative state is reflected in visual signals of lizards from different thermal habitats. According to our hypothesis, efficient thermoregulation requires different strategies in different thermal environments. In a habitat with predictable temperature changes, animals are less exposed to suboptimal temperature ranges and selection will, therefore, be stronger on the maximum oxidative damage at optimal body temperature. Contrarily, in a habitat with rather stochastic thermal shifts, individuals are often constricted by suboptimal thermal conditions, and oxidative damage can be limiting on a wide temperature range. We used Iberolacerta cyreni and Psammodromus algirus inhabiting stochastic and predictable thermal environments respectively. We examined two aspects of oxidative stress: the level of reactive oxygen metabolites at the preferred temperature (maximal ROM) and the temperature range in which animals produce at least 80% of the maximum level of reactive oxygen metabolites (effective ROM range). In I. cyreni, we found that duller coloration was related to a wider effective ROM range, while expression of coloration in P. algirus was negatively correlated with the maximal ROM. Our results suggest that different thermal constraints affect different aspects of oxidative damage which can indicate individual quality and are, therefore, represented in sexual ornaments.


Assuntos
Ecossistema , Lagartos/fisiologia , Estresse Oxidativo/fisiologia , Pigmentação/fisiologia , Comunicação Animal , Animais , Regulação da Temperatura Corporal , Feminino , Masculino , Espécies Reativas de Oxigênio , Caracteres Sexuais , Temperatura
10.
Physiol Biochem Zool ; 92(6): 573-578, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31584858

RESUMO

When females face adverse environmental conditions, physiological changes, such as elevated corticosterone levels, to cope with the stressors may also impact their offspring. Such maternal effects are often considered adaptive and may "prime" the offspring for the same adverse environment, but maternal corticosterone levels do not always match that of the eggs produced. We examined how diet restriction and increased locomotor activity, via exercise training, affected steroid hormone levels of female green anole lizards, as well as the hormone levels in the yolk of their eggs. Diet restriction did not affect female hormone levels, but training increased corticosterone levels. Despite this, training did not affect yolk steroid levels, but eggs from females with diet restriction had lower corticosterone levels in yolk. This suggests that two common stressors, food shortage and increased locomotor activity, impact female physiology in a way that is not translated to her offspring.


Assuntos
Corticosterona/metabolismo , Gema de Ovo/química , Lagartos/fisiologia , Fenômenos Fisiológicos da Nutrição Materna , Condicionamento Físico Animal/fisiologia , Animais , Corticosterona/sangue , Corticosterona/química , Feminino , Lagartos/sangue , Oviposição
11.
Nat Commun ; 10(1): 4077, 2019 09 09.
Artigo em Inglês | MEDLINE | ID: mdl-31501432

RESUMO

Climatic conditions changing over time and space shape the evolution of organisms at multiple levels, including temperate lizards in the family Lacertidae. Here we reconstruct a dated phylogenetic tree of 262 lacertid species based on a supermatrix relying on novel phylogenomic datasets and fossil calibrations. Diversification of lacertids was accompanied by an increasing disparity among occupied bioclimatic niches, especially in the last 10 Ma, during a period of progressive global cooling. Temperate species also underwent a genome-wide slowdown in molecular substitution rates compared to tropical and desert-adapted lacertids. Evaporative water loss and preferred temperature are correlated with bioclimatic parameters, indicating physiological adaptations to climate. Tropical, but also some populations of cool-adapted species experience maximum temperatures close to their preferred temperatures. We hypothesize these species-specific physiological preferences may constitute a handicap to prevail under rapid global warming, and contribute to explaining local lizard extinctions in cool and humid climates.


Assuntos
Meio Ambiente , Variação Genética , Genoma , Lagartos/genética , Lagartos/fisiologia , Temperatura , Animais , Regulação da Temperatura Corporal/fisiologia , Clima , Evolução Molecular , Filogenia
12.
Zool Res ; 40(5): 358-393, 2019 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-31502426

RESUMO

We provide an integrative taxonomic analysis of the Lipinia vittigera species complex from mainland Southeast Asia. Based on examination of external morphology, color pattern, and 681 base pairs of the cytochrome oxidase subunit I (COI) mitochondrial gene, we demonstrate the presence of four morphologically distinct lineages of Lipinia in Vietnam, Cambodia, Thailand, and Malaysia, showing a sequence divergence ranging 15.5%-20.4%. All discovered lineages are discretely diagnosable from one another by a combination of scalation traits and color patterns. A review of the published distribution data and a re-examination of available type material revealed the following results:(1) distribution of L. vittigera (Boulenger, 1894) sensu stricto is restricted to Sundaland and the Thai-Malay Peninsula south of the Isthmus of Kra; (2) L. microcercus (Boettger, 1901) stat. nov. is elevated to full species rank; the species has a wide distribution from central and southern Vietnam across Cambodia to eastern Thailand; we regard Lygosoma vittigerum kronfanum Smith, 1922 and Leiolopisma pranensis Cochran, 1930 as its junior synonyms; (3) Lipinia trivittata sp. nov. occurs in hilly areas of southern Vietnam, Cambodia, and eastern Thailand; and (4) Lipinia vassilievi sp. nov. is currently known only from a narrow area along the Vietnamese-Cambodian border in the foothills of the central Annamite Mountain Range. We further provide an identification key for Lipinia occurring in mainland Southeast Asia.


Assuntos
Lagartos/genética , Lagartos/fisiologia , Pigmentação , Distribuição Animal , Animais , Indochina , Especificidade da Espécie
13.
Behav Processes ; 169: 103963, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31545992

RESUMO

Mammals and birds are capable of navigating to a goal using learned map-like representations of space (i.e. place learning), but research assessing this navigational strategy in reptiles has produced inconclusive results, in part due to the use of procedures that do not take account of the peculiarities of reptilian behavior and physiology. Here I present a procedure suitable for testing spatial cognition that exploits a naturally evolved, ethologically relevant ability common to many lizards (i.e. refuge seeking behavior). The procedure requires lizards to learn the location of an open refuge inside a rectangular arena containing artificial refuges in every corner, using distal extramaze visual cues and with no local cues marking the location of the open refuge. The procedure probes the lizards' place learning ability and effectively rules out the use of egocentric and response-based strategies. The described procedure was successfully used to demonstrate place learning in a lacertid lizard (Podarcis liolepis). Over the course of two weeks of training both the latency to entering the open refuge and the number of corners visited in each trial decreased gradually, indicating that learning had taken place in over 60% of the lizards tested. These results confirm that, under certain circumstances, lizards are capable of navigating to a goal using a place learning strategy.


Assuntos
Comportamento Animal/fisiologia , Lagartos/fisiologia , Aprendizagem Espacial/fisiologia , Memória Espacial/fisiologia , Animais , Cognição , Sinais (Psicologia) , Inteligência
14.
Naturwissenschaften ; 106(9-10): 53, 2019 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-31549238

RESUMO

Sand swimming behaviour occurs in several lizard clades. Known ecological advantages of sand swimming include reduced predation risk and enhanced thermoregulation. We addressed whether, by way of sand abrasion, sand-swimming reduces ectoparasitism in the lizard Microlophus occipitalis, whose natural habitat includes sandy substrates (beach) and firm soil (dry forest). We hypothesised that, aside from habitat differences in infestation probability, ectoparasite prevalence and load would be lower in the beach than in the forest because of ectoparasite removal caused by sand-swimming. In an experiment with lizards confined in boxes with substrate from both habitats, lizards in beach boxes showed a greater decrease in ectoparasite load compared with lizards in forest boxes. Ectoparasite prevalence and load were much higher in the forest than in the beach across seasons. Larger lizards showed higher ectoparasite loads, and there were no sex differences in ectoparasite infestation. We provide evidence that sand swimming may confer another ecological advantage to lizards: reduced ectoparasitism.


Assuntos
Ecossistema , Ectoparasitoses/veterinária , Lagartos/parasitologia , Doenças Parasitárias em Animais/epidemiologia , 24975 , Natação , Animais , Ectoparasitoses/epidemiologia , Ectoparasitoses/parasitologia , Feminino , Lagartos/fisiologia , Masculino , Doenças Parasitárias em Animais/parasitologia , Prevalência
15.
Environ Sci Pollut Res Int ; 26(31): 31717-31729, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31485938

RESUMO

The Argentine giant tegu, a large lizard native to South America, was first discovered as established in the USA in scrub habitats of west-central Florida in 2006. Invasive populations potentially could occupy an extensive range of habitats and in much of the southern United States and Mexico and threaten many native species. The Argentine giant tegu was recently deemed as having a "highest impact concern" among the invasive reptile species most threatening to Florida ecology. Among the most rewarding research directions identified for this species was "having a reliable and practical method to detect/monitor" them. We address this need by evaluating five methods for monitoring Argentine giant tegus on how well each method detected the species and whether the observations were sufficient to quantitatively assess population abundance using a widely applicable framework for indexing animal populations. Passive tracking plots were the most efficient and effective means for detecting tegus and calculating abundance indices but were best suited for late winter to spring before summer rains compacted tracking substrates. Gopher tortoise burrows are often used by tegus and camera traps on their entrances proved able to obtain data suitable for indexing populations but required more labor and expense than tracking plots. Trapping either at gopher tortoise burrows or along drift fences was ineffective at capturing tegus. Similarly, visual encounter transects were not effective for observing tegus.


Assuntos
Espécies Introduzidas/estatística & dados numéricos , Lagartos/fisiologia , Animais , Ecossistema , Florida , México , Estações do Ano , América do Sul
16.
Integr Comp Biol ; 59(4): 1049-1058, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31392321

RESUMO

Over the past decade, ecologists and physiologists alike have acknowledged the importance of environmental heterogeneity. Meaningful predictions of the responses of organisms to climate will require an explicit understanding of how organismal behavior and physiology are affected by such heterogeneity. Furthermore, the responses of organisms themselves are quite heterogeneous: physiology and behavior vary over different time scales and across different life stages, and because physiological systems do not operate in isolation of one another, they need to be considered in a more integrated fashion. Here, we review case studies from our laboratories to highlight progress that has been made along these fronts and generalizations that might be made to other systems, particularly in the context of predicting responses to climate change.


Assuntos
Meio Ambiente , Lagartos/fisiologia , Animais , Clima , Mudança Climática
17.
Life Sci Space Res (Amst) ; 22: 38-46, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31421847

RESUMO

The object play behavior in thick-toed geckos (Chondrodactylus turneri GRAY 1864) was studied during a 30-day orbital experiment onboard the Bion-M1 biosatellite. The play object for five geckos was a marking collar that one of the geckos in the flight group removed immediately before the launch. The play behavior started when either the gecko observed the approaching floating collar or when the gecko independently approached the stationary collar, followed by manipulation of the collar and subsequent observation of its moving away. While playing with the collar, the individuality of geckos' behavior was manifested in the frequency and number of play episodes, the nature of manipulations, and the duration of interest in play during the flight. We found that thick-toed geckos could play not only with an unknown object (marking collar) but also with familiar molting skins. In weightlessness, the play behavior of geckos with molting skin fragments was similar to the play behavior with the collar and also varied between individuals. It was established that geckos maintained a similar individual level of play activity with different objects (collar and molting skins). It was found that geckos also played with fragments of molting skin under normal gravity conditions. In contrast to weightlessness, play behavior at normal gravity was rare and limited to short durations of object manipulation.


Assuntos
Lagartos/fisiologia , Voo Espacial , Ausência de Peso , Adaptação Fisiológica , Animais , Comportamento Animal , Feminino , Astronave , Gravação em Vídeo
18.
Behav Processes ; 167: 103937, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31400395

RESUMO

Many animals use their excrements to communicate with others. In order to increase signal efficacy, animals often behaviourally select for specific defecation sites that maximize the detectability of their faecal deposits, such as the tip of rocks by some lizard species. However, the field conditions in which these observations are made make it difficult to reject alternative explanations of defecation site preference; rock tips may also provide better opportunities for thermoregulation, foraging, or escaping predators, and not solely for increasing the detectability of excrements. In addition, we still know little on whether lizard defecation behaviour varies within-species. In this laboratory study, we take an experimental approach to test defecation site preference of Podarcis melisellensis lizards in a standardized setting, and assess whether preferences differ between sexes, and among populations. Our findings show that in an environment where all stones provide equal thermoregulatory advantage, prey availability, and predator pressure, lizards still select for the largest stone in their territory as preferred defecation site. Moreover, we demonstrate that lizards' defecation preference is a strong conservative behaviour, showing no significant intraspecific variation. Together, these findings corroborate the idea that lizards may defecate on prominent rocky substrates in order to increase (visual) detectability of the deposited faecal pellets.


Assuntos
Comportamento Animal/fisiologia , Comportamento de Escolha/fisiologia , Defecação/fisiologia , Lagartos/fisiologia , Animais , Regulação da Temperatura Corporal
19.
Zoology (Jena) ; 135: 125690, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31383295

RESUMO

In this study, we investigated the reproductive biology of the small lizard Eurolophosaurus nanuzae based on evidence of sperm storage by females and variations of the renal sexual segment (RSS) in males. We found a remarkable occurrence of crypts containing bundles of sperm and secretions in the epithelium of E. nanuzae oviducts. The chemical composition of the secretions associated with the sperm within the crypts was similar to secretions from the oviductal epithelium, which suggests that females can produce substances involved in the maintenance of stored sperm. Female sperm storage does not occur over the span of years for long-term reproduction; the majority of females with stored sperm occurred during the peak and late periods of the reproductive season. We discuss this result in relation to post-copulatory sexual selection strategies in the context of sperm competition for restricted successful fertilisation. In males, testicular activity was continuous, while RSS activity varied seasonally, in synchrony with female reproductive activity. Throughout the reproductive season, the RSS was hypertrophied, with maximum activity during the peak of the reproductive season. The lowest RSS activity occurred when females were not reproductive (non-reproductive season). Considering that RSS secretions are essential for reproduction, an absence or reduction of these secretions during the non-reproductive season may imply the reduced functionality of sperm during this period. Since sperm production continues throughout the whole reproductive cycle in E. nanuzae males, RSS activity could be an important indicator of reproduction, beyond testicular activity.


Assuntos
Lagartos/anatomia & histologia , Lagartos/fisiologia , Animais , Feminino , Gônadas , Masculino , Oviductos/anatomia & histologia , Reprodução/fisiologia , Comportamento Sexual Animal/fisiologia , Espermatozoides
20.
J Chem Ecol ; 45(8): 673-683, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31407198

RESUMO

Animals modulate intraspecific signal shape and intensity, notably during reproductive periods. Signal variability typically follows a seasonal scheme, traceable through the expression of visual, acoustic, chemical and behavioral patterns. The chemical channel is particularly important in lizards, as demonstrated by well-developed epidermal glands in the cloacal region that secrete lipids and proteins recognized by conspecifics. In males, the seasonal pattern of gland activity is underpinned by variation of circulating androgens. Changes in the composition of lipid secretions convey information about the signaler's quality (e.g., size, immunity). Presumably, individual identity is associated with a protein signature present in the femoral secretions, but this has been poorly investigated. For the first time, we assessed the seasonal variability of the protein signal in relation to plasma testosterone level (T), glandular activity and the concentration of provitamin D3 in the lipid fraction. We sampled 174 male common wall lizards (Podarcis muralis) over the entire activity season. An elevation of T was observed one to two months before the secretion peak of lipids during the mating season; such expected delay between hormonal fluctuation and maximal physiological response fits well with the assumption that provitamin D3 indicates individual quality. One-dimensional electrophoretic analysis of proteins showed that gel bands were preserved over the season with an invariant region; a result in agreement with the hypothesis that proteins are stable identity signals. However, the relative intensity of bands varied markedly, synchronously with that of lipid secretion pattern. These variations of protein secretion suggest additional roles of proteins, an issue that requires further studies.


Assuntos
Glândulas Exócrinas/metabolismo , Lipídeos/análise , Lagartos/fisiologia , Proteínas de Répteis/análise , Animais , Desidrocolesteróis/análise , Eletroforese em Gel de Campo Pulsado , Cromatografia Gasosa-Espectrometria de Massas , Metabolismo dos Lipídeos , Lipídeos/química , Masculino , Análise de Componente Principal , Estações do Ano , Comportamento Sexual Animal , Testosterona/sangue
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