Morphological and Physiological Changes during Reproduction and Their Relationships to Reproductive Performance in a Capital Breeder

Self Cite

Resource availability can impact immune function, with the majority of studies of such influences focusing on the allocation of energy investment into immune versus other physiological functions. When energy is a limited resource, performance trade-offs can result, compromising immunity. Dehydration is also considered a physiological challenge resulting from the limitation of a vital resource, yet previous research has found a positive relationship between dehydration and innate immune performance. However, these studies did not examine the effects of dehydration on immunity when there was another concurrent, substantial physiological challenge. Thus, we examined the impact of reproduction and water deprivation, individually and in combination, on immune performance in Children's pythons (Antaresia childreni). We collected blood samples from free-ranging A. childreni to evaluate osmolality and innate immune function (lysis, agglutination, bacterial growth inhibition) during the austral dry season, when water availability is limited and this species is typically reproducing. To examine how reproduction and water imbalance, both separately and combined, impact immune function, we used a laboratory-based 2 × 2 experiment. Our results demonstrate that A. childreni experience significant dehydration during the dry season and that, overall, osmolality, regardless of the underlying cause (seasonal rainfall, water deprivation, or reproduction), is positively correlated with increased innate immune performance.

Section: Discussionmentioning

confidence: 73%

Reproduction Alters Hydration State but Does Not Impact the Positive Effects of Dehydration on Innate Immune Function in Children’s Pythons (Antaresia childreni)

Brusch

Billy

Blattman

et al. 2017

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“…The aspic viper Vipera aspis is a small, viviparous snake of the western Paleartic region, and the thermal and reproductive physiology of this species has been intensely studied (Saint Girons 1952;Bonnet et al 2001;Lourdais et al 2002; q3 Dupoué and Lourdais 2014). Gestation begins in early June (Naulleau 1981), and pregnant females have a higher preferred body temperature and bask more than nonreproductive females (Lorioux et al 2013;Stahlschmidt et al 2013). Parturition occurs in late August to early September (Lourdais et al 2004b).…”

Section: Study Speciesmentioning

confidence: 99%

Hydric “Costs” of Reproduction: Pregnancy Increases Evaporative Water Loss in the SnakeVipera aspis

Lourdais

Dupoué

Guillon

et al. 2017

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Water constraints can mediate evolutionary conflict either among individuals (e.g., parent-offspring conflict, sexual conflict) or within an individual (e.g., cost of reproduction). During pregnancy, water is of particular importance because the female provides all water needed for embryonic development and experiences important maternal shifts in behavior and physiology that, together, can compromise female water balance if water availability is limited. We examined the effect of pregnancy on evaporative water loss and microhabitat selection in a viviparous snake, the aspic viper. We found that both physiological (increased metabolism and body temperature) and morphological (body distension) changes contribute to an increased evaporative water loss in pregnant females. We also found that pregnant females in the wild select warmer and moister basking locations than nonreproductive females, likely to mitigate the conflict between thermal needs and water loss. Water resources likely induce significant reproductive constraints across diverse taxa and thus warrant further consideration in ecological research. From an evolutionary perspective, water constraints during reproduction may contribute to shaping reproductive effort.

“…Although snakes from temperate regions exhibit variation in metrics of oxidative stress and immune function because of a range of variables (e.g., reproduction, feeding, restraint stress, and sex; Stahlschmidt et al 2013;Neuman-Lee et al 2015;Butler et al 2016;Luoma et al 2016), the lability of TPCs for these physiological metrics is unknown. Also, temperate snakes may actually experience population-and individual-level benefits from warming (Sperry et al 2010;Weatherhead et al 2012;Huang et al 2013;Stahlschmidt et al 2015b).…”

Section: Introductionmentioning

confidence: 99%

A Simulated Heat Wave Has Diverse Effects on Immune Function and Oxidative Physiology in the Corn Snake (Pantherophis guttatus)

Stahlschmidt

French

Ahn

et al. 2017

Animals will continue to encounter increasingly warm environments, including more frequent and intense heat waves. Yet the physiological consequences of heat waves remain equivocal, potentially because of variation in adaptive plasticity (reversible acclimation) and/or aspects of experimental design. Thus, we measured a suite of physiological variables in the corn snake (Pantherophis guttatus) after exposure to field-parameterized, fluctuating temperature regimes (moderate temperature and heat wave treatments) to address two hypotheses: (1) a heat wave causes physiological stress, and (2) thermal performance of immune function exhibits adaptive plasticity in response to a heat wave. We found little support for our first hypothesis because a simulated heat wave had a negative effect on body mass, but it also reduced oxidative damage and did not affect peak performance of three immune metrics. Likewise, we found only partial support for our second hypothesis. After exposure to a simulated heat wave, P. guttatus exhibited greater performance breadth and reduced temperature specialization (the standardized difference between peak performance and performance breadth) for only one of three immune metrics and did so in a sex-dependent manner. Further, a simulated heat wave did not elicit greater performance of any immune metric at higher temperatures. Yet a heat wave likely reduced innate immune function in P. guttatus because each metric of innate immune performance in this species (as in most vertebrates) was lower at elevated temperatures. Together with previous research, our study indicates that a heat wave may have complex, modest, and even positive physiological effects in some taxa.