Variation in cottonmouth (Agkistrodon piscivorus leucostoma) resting metabolic rates

Zaidan, Frederic

doi:10.1016/s1095-6433(02)00344-6

Cited by 29 publications

(15 citation statements)

References 34 publications

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“…Lower Hct may provide significant advantages by reducing vascular resistance. Finally, boids and viperids represent low‐energy specialists (Bedford & Christian, ; Zaidan, ; McCue, 2007b) and these two clades show the lowest Hct on average (Brischoux et al ., : fig. 2).…”

Section: Discussionmentioning

confidence: 99%

Ambush or active life: foraging mode influences haematocrit levels in snakes

Lourdais

Gartner

Brischoux

2014

Biol J Linn Soc Lond

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The rate at which organisms acquire resources is a critical trait and foraging mode can vary from sit-and-wait tactics to being highly mobile and active. Snakes provide a robust opportunity to examine the physiological correlates of contrasted foraging strategies. In this context, haematocrit (Hct), a proxy of blood oxygen carrying capacity, should be a reliable indicator of aerobic activity levels. We used phylogenetically informed models to examine the relationship between foraging mode and Hct in 80 snake species. After accounting for clade and habitat effects, we found a significant relationship of Hct with foraging mode; Hct is lower in snakes that ambush prey compared to active foragers across habitats. Species using both foraging tactics had marginally lower Hct than active foragers. Ambush foraging tactics are widespread in snakes, notably among low-energy specialists that usually display low feeding frequency, as well as limited activity and daily movements. Because Hct influences blood viscosity, low levels may thus be advantageous by reducing maintenance and locomotory costs. Further studies are required to better understand the implication of foraging mode on blood characteristics and other aspects of snake physiology.

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Section: Discussionmentioning

confidence: 99%

Ambush or active life: foraging mode influences haematocrit levels in snakes

Lourdais

Gartner

Brischoux

2014

Biol J Linn Soc Lond

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“…For example, metabolic rate can be temperature insensitive within a range (Aleksiuk, 1971;Seidel and Lindeborg, 1973), be dependent on ecological role (e.g. foraging strategy; Andrews and Pough, 1985;Angilletta, 2001;Beaupre, 1993;Sears, 2005;Taylor and Davies, 1981;Zaidan, 2003;Zari, 2013) or exhibit temperature-dependent scaling with body size (Buikema and Armitage, 1969;Dmi'el, 1972;Gangloff et al, 2015;Vinegar et al, 1970). Both the standard effect of temperature to increase metabolic rate and the capacity of organisms to adjust that relationship (for example, via the effects of glucocorticoids) will determine the energetic cost of high-temperature exposure.…”

Section: Introductionmentioning

confidence: 99%

Hormonal and metabolic responses to upper temperature extremes in divergent life-history ecotypes of a garter snake

Gangloff

Holden

Telemeco

et al. 2016

Journal of Experimental Biology

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Extreme temperatures constrain organismal physiology and impose both acute and chronic effects. Additionally, temperature-induced hormone-mediated stress response pathways and energetic tradeoffs are important drivers of life-history variation. This study employs an integrative approach to quantify acute physiological responses to high temperatures in divergent life-history ecotypes of the western terrestrial garter snake (Thamnophis elegans). Using wild-caught animals, we measured oxygen consumption rate and physiological markers of hormonal stress response, energy availability and anaerobic respiration in blood plasma across five ecologically relevant temperatures (24, 28, 32, 35 and 38°C; 3 h exposure). Corticosterone, insulin and glucose concentrations all increased with temperature, but with different thermal response curves, suggesting that high temperatures differently affect energy-regulation pathways. Additionally, oxygen consumption rate increased without plateau and lactate concentration did not increase with temperature, challenging the recent hypothesis that oxygen limitation sets upper thermal tolerance limits. Finally, animals had similar physiological thermal responses to high-temperature exposure regardless of genetic background, suggesting that local adaptation has not resulted in fixed differences between ecotypes. Together, these results identify some of the mechanisms by which higher temperatures alter hormonal-mediated energy balance in reptiles and potential limits to the flexibility of this response.

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“…Boas and pythons are renowned among squamates for their low metabolic requirements (Bedford 1998;Zaidan 2003), very large lipid storage, and extreme fasting abilities. Reproduction can be sustained without any food intake (Rivas 1999), which results in pure capital-breeding systems.…”

Section: Introductionmentioning

confidence: 99%

Structural and Performance Costs of Reproduction in a Pure Capital Breeder, the Children’s PythonAntaresia childreni

Lourdais¹,

Lorioux²,

DeNardo³

2013

Physiological and Biochemical Zoology

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Females often manage the high energy demands associated with reproduction by accumulating and storing energy in the form of fat before initiating their reproductive effort. However, fat stores cannot satisfy all reproductive resource demands, which include considerable investment of amino acids (e.g., for the production of yolk proteins or gluconeogenesis). Because capital breeders generally do not eat during reproduction, these amino acids must come from internal resources, typically muscle proteins. Although the energetic costs of reproduction have been fairly well studied, there are limited data on structural and performance costs associated with the muscle degradation required to meet amino acid demands. Thus, we examined structural changes (epaxial muscle width) and performance costs (constriction and strength) over the course of reproduction in a pure capital breeder, the children's python (Antaresia childreni). We found that both egg production (i.e., direct resource allocation) and maternal care (egg brooding) induce muscle catabolism and affect performance of the female. Although epaxial muscle loss was minimal in nonreproductive females, it reached up to 22% (in females after oviposition) and 34% (in females after brooding) of initial muscle width. Interestingly, we found that individuals with higher initial muscular condition allocated more of their muscle into reproduction. The amount of muscle loss was significantly linked to clutch mass, underscoring the role of structural protein in egg production. Egg brooding significantly increased proteolysis and epaxial loss despite no direct allocation to the offspring. Muscle loss was linked to a significant reduction in performance in postreproductive females. Overall, these results demonstrate that capital-breeding females experience dramatic costs that consume structural resources and jeopardize performance.

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Variation in cottonmouth (Agkistrodon piscivorus leucostoma) resting metabolic rates

Cited by 29 publications

References 34 publications

Ambush or active life: foraging mode influences haematocrit levels in snakes

Ambush or active life: foraging mode influences haematocrit levels in snakes

Hormonal and metabolic responses to upper temperature extremes in divergent life-history ecotypes of a garter snake

Structural and Performance Costs of Reproduction in a Pure Capital Breeder, the Children’s PythonAntaresia childreni

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