Thermoregulation in Nocturnal Ecthotherms: Seasonal and Intraspecific Variation in the Mediterranean Gecko (Hemidactylus turcicus)

Hitchcock, Michael A.; McBrayer, Lance D.

doi:10.1670/233-04a.1

Cited by 45 publications

(36 citation statements)

References 39 publications

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“…These data provided preliminary evidence that leaf-toed geckos achieved a regulated body temperature during the day, when hiding inside retreat sites. High body temperatures may be obtained by retreat-site selection or postural adjustments as demonstrated in the Australian gecko Christinus marmoratus (Kearney and Predavec 2000) and in other temperate species such as Eublepharis macularius (Autumn and De Nardo 1995) and Hemidactylus turcicus (Hitchcock and McBrayer 2006).…”

Section: Discussionmentioning

confidence: 99%

“…Moreover, solar radiation in kJ/m 2 measured during the gecko active season (April-October) was used. This variable could influence thermoregulation efficiency of geckos (Hitchcock and McBrayer 2006) particularly of gravid females (Rock et al 2002). Local climate data were obtained from Genova University weather station (www.diam.unige.it) about 2 km from the study site.…”

Section: Study Species Site and Climatic Variablesmentioning

confidence: 99%

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Density regulation in the Mediterranean leaf‐toed gecko Euleptes europaea

Salvidio

Oneto

2008

Ecological Research

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Isolated populations are particularly prone to extinction, and understanding their temporal dynamics is relevant for conservation and management. In this study, the abundance of a population of the nocturnal leaf-toed gecko Euleptes europaea was estimated by mark-recapture over a 12-year period in northwest Italy. Simulation tests showed the presence of density-dependence, and autoregressive analyses indicated that direct density dependence was responsible for a large part of the variation in population growth rates. Density-dependent recruitment was suggested as the main demographic mechanism controlling population dynamics, which was also affected by solar radiation measured during the active gecko season. These results may contribute to implement conservation strategies in other small and isolated leaf-toed gecko populations.

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Section: Discussionmentioning

confidence: 99%

Section: Study Species Site and Climatic Variablesmentioning

confidence: 99%

Density regulation in the Mediterranean leaf‐toed gecko Euleptes europaea

Salvidio

Oneto

2008

Ecological Research

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“…Species of this genus has been used as model organisms to design a methodology to characterize thermoregulatory strategy in reptiles (Hertz et al, 1993); a protocol widely used since then (Díaz & Cabezas-Díaz, 2004;Blouin-Demers & Nadeau, 2005;Hitchcock & McBrayer, 2006;Row & BlouinDemers, 2006;Herczeg et al, 2008). Studies on Anolis have showed that thermoregulatory strategy varies among species, elevations and seasons, revealing high behavioral and physiological plasticity for dealing with the challenges imposed by the environment (Huey & Webster, 1975;Hertz & Huey, 1981;Hertz, 1981;Hertz et al, 1993;Muñoz et al, 2014).…”

Section: Palabras-clavementioning

confidence: 99%

Thermoregulation in the Andean lizard Anolis heterodermus (Squamata: Dactyloidae) at high elevation in the Eastern Cordillera of Colombia.

Méndez-Galeano

Calderón‐Espinosa

2017

Iheringia, Sér. Zool.

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ABSTRACT. Low thermal quality environments, such extreme latitudes or high elevation regions, are highly expensive for reptiles in terms of thermoregulation. Thus, physiological adaptations or behavioral adjustments to live in these habitats have evolved in some species. Anolis heterodermus (Duméril, 1851) is an anole lizard that lives at high elevations in the Andes region. In this paper, we attempted to elucidate the thermoregulation strategy of a population of this species from the eastern cordillera of Colombia during wet and dry seasons. We measured body temperatures (T b ), operative temperatures (T e ) and preferred temperatures (T pref ). Based on these data, we obtained accuracy (d̄b), environmental thermal quality (d̄e) and effi ciency of thermoregulation (E) indexes. There were no signifi cant diff erences of T b or d̄b between seasons, sexes, ages, and for T pref between sexes or ages, but we found diff erences in T e and d̄e between seasons. The indexes suggested high thermoregulatory accuracy, low thermal environment quality and indicated that A. heterodermus was an active thermoregulator in both seasons. Broad ranges of T b and the species association with microhabitats with high solar radiation suggest eurythermy and heliothermy. Anolis heterodermus lives in a low thermal quality habitat, using exposed perches, which seems the most effi cient thermal microhabitats. We concluded that A. heterodermus performed behavioral adjustment for compensating seasonal variation in the environmental thermal costs.KEYWORDS. Thermal quality, thermoregulatory accuracy, seasonal variation, heliothermy.RESUMEN. Termorregulación en el lagarto andino Anolis heterodermus (Squamata: Dactyloidae) a una alta elevación en la Cordillera Oriental de Colombia. Ambientes con baja calidad térmica, tales como las latitudes extremas o regiones en altas elevaciones, son altamente costosos para los reptiles en términos de termorregulación, por lo cual algunas especies han adquirido adaptaciones fi siológicas o ajustes conductuales para habitar estos ambientes. Anolis heterodermus (Duméril, 1851) es un lagarto que habita a altas elevaciones en la región andina. En el presente trabajo se evaluó la termorregulación de una población de esta especie en la cordillera oriental de Colombia durante las épocas húmeda y seca. Se midieron temperaturas corporales (T b ), operativas (T e ) y de preferencia (T pref ). Con base en estas variables, se obtuvieron los índices de calidad térmica ambiental (d̄e), exactitud (d̄b) y efi ciencia (E) de la termorregulación. No hubo diferencias signifi cativas entre la T b o d̄b entre épocas, sexos o edades y tampoco de la T pref entre sexos o edades, pero encontramos diferencias de T e y d̄e entre épocas. Los índices sugieren alta exactitud termorreguladora y baja calidad térmica del ambiente, por lo tanto indican que A. heterodermus es un termorregulador activo para ambas épocas. El amplio intervalo de T b y la asociación de la especie a microhábitats con alta radiación solar sugieren euritérmia y heliot...

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“…frenatus and closely related species have found that although nocturnal they have a high preferred body temperature and therefore perform at sub-optimal levels due to reduced temperatures during activity times and little ability to thermoregulate Hitchcock and McBrayer, 2006). However, some gecko species thermoregulate during the day when a more variable thermal environment exists (Hitchcock and McBrayer, 2006).…”

Section: Study Speciesmentioning

confidence: 99%

“…However, some gecko species thermoregulate during the day when a more variable thermal environment exists (Hitchcock and McBrayer, 2006).…”

Section: Study Speciesmentioning

confidence: 99%

Sex-specific variation in morphology and performance in the Asian house gecko

Cameron¹

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Ever since Darwin's theory of sexual selection was first published, understanding the evolutionary mechanisms that lead to sex-specific traits and quantifying patterns therein has been a large focus of evolutionary ecologists. Sexual variation in phenotypes in form and function is ubiquitous in nature, and its extent varies widely, within closely related groups and even species. Understanding patterns and the circumstances under which sexually divergent phenotypes evolve requires an understanding of both the proximate and evolutionary mechanisms involved. While studies have primarily focused on sex-specific morphological traits such as size and secondary trait dimorphism, less attention has been given to the functional differences between the sexes. From an evolutionary perspective, sexspecific traits result from many factors that act differentially on each sex, modifying phenotypic and behavioural components that influence the capacity of fulfilling reproductive roles. Therefore, sexual selection alone does not define the magnitude of phenotypic divergence between the sexes, but it is rather the interplay between sexual and natural selection and their interactions with the environment. Intraspecific studies investigating associations between form and function of sexspecific traits provide a useful tool to understand the fundamental mechanisms that lead to the evolution of complex traits in males and females. The overall aim of this thesis was to gain a better understanding of the evolutionary mechanisms that drive patterns in sex-specific phenotypes, using a territorial gecko species (Hemidactylus frenatus) distributed over a large latitudinal cline.The first aim of this thesis was to examine the potential trade-offs between performance functions associated with reproductive success and to test whether compensatory mechanisms may obscure the detection of such costs (Chapter 2). Fighting capacity and escape performance of male H. frenatus are likely to pose conflicting demands on the optimum phenotype for each task. Highly territorial and aggressive males may require greater investment in head size/strength but such an enhancement may reduce overall escape performance. To test this idea, the second aim (also in Chapter 2) was to determine the role of morphological and functional traits in determining the outcome of male-male combat (reproductive success) and prey-capture ability (survivorship).Among male geckos, I found that larger head size resulted in greater biting capacity, but at a cost of reduced spring performance. Females, however, showed no evidence of this trade-off. The sex specificity of this trade-off suggests that the sexes differ in their optimal strategies for dealing with the conflicting requirements of bite force and sprint speed. Unlike males, female H. frenatus had a positive association between hind-limb length and head size, suggesting that they have utilised a compensatory mechanism to alleviate the possible locomotor costs of larger head sizes. It appears that there is greater sel...

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Thermoregulation in Nocturnal Ecthotherms: Seasonal and Intraspecific Variation in the Mediterranean Gecko (Hemidactylus turcicus)

Cited by 45 publications

References 39 publications

Density regulation in the Mediterranean leaf‐toed gecko Euleptes europaea

Density regulation in the Mediterranean leaf‐toed gecko Euleptes europaea

Thermoregulation in the Andean lizard Anolis heterodermus (Squamata: Dactyloidae) at high elevation in the Eastern Cordillera of Colombia.

Sex-specific variation in morphology and performance in the Asian house gecko

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