Adaptations of the Amphibian, Scaphiopus couchi, to Desert Conditions

Mayhew, Wilbur W.

doi:10.2307/2423123

Cited by 80 publications

(48 citation statements)

References 14 publications

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“…In comparison, the Couch's spadefoot toad (Scaphiopus couchii) uses its clawed hindlegs to burrow into sandy substrate (Mayhew, 1965). Wood frogs, without claws, may rotate instead of dig as the soil likely requires less effort for the wood frog to compact than displace.…”

Section: Discussionmentioning

confidence: 99%

Wood frog adaptations to overwintering in Alaska: New limits to freezing tolerance

Larson

Middle

et al. 2014

Journal of Experimental Biology

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We investigated the ecological physiology and behavior of free-living wood frogs [Lithobates (Rana) sylvaticus] overwintering in Interior Alaska by tracking animals into natural hibernacula, recording microclimate, and determining frog survival in spring. We measured cryoprotectant (glucose) concentrations and identified the presence of antifreeze glycolipids in tissues from subsamples of naturally freezing frogs. We also recorded the behavior of wood frogs preparing to freeze in artificial hibernacula, and tissue glucose concentrations in captive wood frogs frozen in the laboratory to −2.5°C. Wood frogs in natural hibernacula remained frozen for 193±11 consecutive days and experienced average (October-May) temperatures of −6.3°C and average minimum temperatures of -14.6±2.8°C (range −8.9 to −18.1°C) with 100% survival (N=18). Mean glucose concentrations were 13-fold higher in muscle, 10-fold higher in heart and 3.3-fold higher in liver in naturally freezing compared with laboratory frozen frogs. Antifreeze glycolipid was present in extracts from muscle and internal organs, but not skin, of frozen frogs. Wood frogs in Interior Alaska survive freezing to extreme limits and durations compared with those described in animals collected in southern Canada or the Midwestern United States. We hypothesize that this enhancement of freeze tolerance in Alaskan wood frogs is due to higher cryoprotectant levels that are produced by repeated freezing and thawing cycles experienced under natural conditions during early autumn.

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Section: Discussionmentioning

confidence: 99%

Wood frog adaptations to overwintering in Alaska: New limits to freezing tolerance

Larson

Middle

et al. 2014

Journal of Experimental Biology

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“…First, there are no reliable estimates of intensities of natural selection on the traits measured in this study. No data exist on selection on head width in tree frogs, and although strong directional selection on growth rate and larval period has been demonstrated in temporary-pond-breeding species (Mayhew, 1965;Tevis, 1966;Brodie and Formanowicz, 1983;Smith, 1983;Travis, 1983;Travis et al, 1985), it would be risky to extrapolate to a permanent-pond species such as Hyla cinerea. Second, genetic correlations sometimes do not accurately predict correlated response for more than a few generations (e.g., Clayton et al, 1957;Bohren et al, 1966;Frankham et al, 1968).…”

Section: Correlations Between Morphometric Andmentioning

confidence: 99%

GENETIC CORRELATIONS AMONG MORPHOMETRIC TRAITS AND RATES OF GROWTH AND DIFFERENTIATION IN THE GREEN TREE FROG,HYLA CINEREA

Blouin

1992

Evolution

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Abstract. -It is often proposed that the morphometric shape ofanimals often evolves as a correlated response to selection on life-history traits such as whole-body growth and differentiation rates. However, there exists little empirical information on whether selection on rates of growth or differentiation in animals could generate correlated response in morphometric shape beyond that owing to the correlation between these rates and body size. In this study genetic correlations were estimated among growth rate, differentiation rate, and body-size-adjusted head width in the green tree frog, Hyla cinerea. Head width was adjusted for size by using the residuals from log-log regressions of head width on snout-vent length. Size-adjusted head width at metamorphosis was positively genetically correlated with larval period length. Thus, size-independent shape might evolve as a correlated response to selection on a larval life-history trait. Larval growth rate was not significantly genetically correlated with size-adjusted head width. An additional morphometric trait, size-adjusted tibiofibula length, had a non normal distribution of breeding values, and so was not included in the analysis of genetic correlations (offspring from one sire had unusually short legs). This result is interesting because, although using genetic covariance matrices to predict longterm multivariate response to selection depends on the assumption that all loci follow a multivariate Gaussian distribution of allelic effects, few data are available on the distribution of breeding values for traits in wild populations. Size at metamorphosis was positively genetically correlated with larval period and larval growth rate. Quickly growing larvae that delay metamorphosis therefore emerge at a large size. The genetic correlation between larval growth rate andjuvenile (postmetamorphic) growth rate was near zero. Growth rate may therefore be an example of a fitness-related trait that is free to evolve in one stage of a complex life cycle without pleiotropic constraints on the same trait expressed in the other stage. Gould (1977) argued that morphometric shape in animals often evolves as a correlated response to selection on life-history traits such as whole-body rates ofgrowth or differentiation. This scenario is true by definition for shape variation that scales nonisometrically with overall body size (because if development rate variation causes size variation at the age or stage at which measurements are taken, then development rate is necessarily correlated with shape). It is not clear whether morphometric shape is genetically correlated with growth or differentiation rate independent ofbody size. Such a correlation would arise if the allometric relationship between shape and size is not constant, but is a function of development rate (e.g., changes in overall growth rate do not affect the growth rate of all body parts , Present address: Department of Biology, Sonoma State University, 180 I East Cotati Ave., Rohnert Park, CA 94928 USA.proportionately; ...

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“…A seleção de microhábitats é essencial para a sobrevivência de muitos anuros estivadores, mas certas espécies estivam em microhábitats que não parecem minimizar os desafios fisiológicos relacionados à potencial perda de água ou a exposição a temperaturas extremas durante a estivação (MAYHEW, 1965;KOBELT et al, 1995). Contudo, na maior parte das espécies estivadoras o hábito de se enterrar é importante para minimizar os efeitos causados pela seca e altas temperaturas a que estariam sujeitos na superfície (CARTLEDGE et al, 2006a;BENTLEY, 1966;BOOTH, 2006;MAYHEW, 1965;SEYMOUR, 1973a).…”

Section: Desafios Comportamentais E Ecofisiológicos De Anuros Estivadunclassified

“…Contudo, na maior parte das espécies estivadoras o hábito de se enterrar é importante para minimizar os efeitos causados pela seca e altas temperaturas a que estariam sujeitos na superfície (CARTLEDGE et al, 2006a;BENTLEY, 1966;BOOTH, 2006;MAYHEW, 1965;SEYMOUR, 1973a). A combinação entre o hábito de se enterrar e a diminuição da taxa metabólica durante a estivação leva os animais a pouparem seus estoques energéticos e reduzirem a perda de água (WITHERS & THOMPSON, 2000).…”

Section: Desafios Comportamentais E Ecofisiológicos De Anuros Estivadunclassified

“…Parece que P. diplolistris escolhe abrigos com disponibilidade aparentemente maior de água e com menores variações de temperatura durante a estação seca, como reportado para S. couchii (MAYHEW, 1965). Mais ainda, Scaphiopus hammondii, é encontrado em solo arenoso durante o inverno, enquanto no verão, que correspondente à estação chuvosa, é encontrado em solo argiloso próximo a corpos de água (SEYMOUR, 1973b (HUDSON & FRANKLIN, 2002b;HUDSON et.…”

Section: Taxa Metabólica De Repouso E Durante O Exercíciounclassified

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Aspectos fisiológicos e ecológicos da estivação em Pleurodema diplolistris (Leiuperidae/Anura)

Pereira¹

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AGRADECIMENTOSAgradeço primeiramente a Deus por ter me dado forças para chegar até aqui. Por ter me guiado e sustentado durante essa trajetória.Agradeço ao Professor Doutor Carlos Navas pela dedicação, apoio e por todas as oportunidades que me ofereceu. Por ter acreditado no meu trabalho e me orientado.Agradeço ao Professor Doutor José Eduardo de Carvalho por ter me ajudado e orientado com muita paciência em todos os momentos. Finalmente, quero agradecer à minha família. Agradeço muito à minha mãe, Angelita por ter costurado durante muitas madrugadas para me ajudar, ao meu pai, Zeca, por ter passado tanto tempo sem dormir para auxiliar-me e agradeço também a minha irmã, Sandra, pelo auxílio. Agradeço muito por terem acreditado em mim e apoiado-me sempre. Agradeço ao Professores

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Adaptations of the Amphibian, Scaphiopus couchi, to Desert Conditions

Cited by 80 publications

References 14 publications

Wood frog adaptations to overwintering in Alaska: New limits to freezing tolerance

Wood frog adaptations to overwintering in Alaska: New limits to freezing tolerance

GENETIC CORRELATIONS AMONG MORPHOMETRIC TRAITS AND RATES OF GROWTH AND DIFFERENTIATION IN THE GREEN TREE FROG,HYLA CINEREA

Aspectos fisiológicos e ecológicos da estivação em Pleurodema diplolistris (Leiuperidae/Anura)

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