Oxidative stress in aspic vipers facing pregnancy and water constraints

Abstract

The physiological mechanisms underlying the 'cost of reproduction' remain under debate, though oxidative stress has emerged as a potential candidate. The 'oxidative cost of reproduction' has received considerable attention with regards to food and antioxidant availability; however, the limitation of water availability has thus far been neglected. In this study, we experimentally examined the combined effect of pregnancy and water deprivation on oxidative status in a viviparous snake (Vipera aspis), a species naturally exposed to periods of water and food deprivation. We predicted a cumulative effect of pregnancy and dehydration on oxidative stress levels. Our results support the occurrence of an oxidative cost of reproduction as we found higher oxidative damage levels in pregnant females than in non-reproductive individuals, despite an upregulation of antioxidant defences. Surprisingly, water deprivation was associated with an up-regulation of antioxidant defences, and did not increase oxidative damage, either alone or in combination with reproduction.

Water availability and temperature induce changes in oxidative status during pregnancy in a viviparous lizard

“…However in both our cross‐sectional and experimental analyses, an increase in antioxidants was obviously not sufficient to fully shield the increase in oxidative damage. Based on our combined approach, our results followed the prediction that temperature and water may modulate such changes in oxidative status during reproduction (Stier et al, ). As an heliothermic ectotherm with affinities for relatively wet habitats, the common lizard has a strong dependence on basking opportunities and water availability for individual maintenance and annual reproduction (Bleu et al, ; Lorenzon et al, ; Marquis et al, ).…”

“…Notably, given the dual requirement of mother and embryos for free water, restriction of water during pregnancy in viviparous species may exacerbate costs of reproduction (Lourdais et al, ) and intergenerational conflicts (Dupoué et al, ; Dupoué, Le Galliard, et al, ). Understanding the proximate mechanism of reproductive trade‐offs induced by oxidative status remains elusive [but see (Stier et al, )]. Given the lack of data, there is a critical need to examine the relationships between oxidative status and fitness outcomes, such as long‐term survival or future reproduction (Speakman et al, ).…”

When water interacts with temperature: Ecological and evolutionary implications of thermo‐hydroregulation in terrestrial ectotherms

“…The shape of the whole-organism hydric performance curves has been little examined relative to thermal performance curves, but there is a strong indication from most published studies for an optimal hydration state that is a critical homeostatic target (Figure 2b). To reach this optimal water balance, hydroregulation involves three major mechanisms: (a) water conservation processes such as physiological changes in skin resistance and panting (Tattersall, Cadena, & Skinner, 2006;Wegener, Gartner, & Losos, 2014), behavioral changes in activity and posture (Chown, Sørensen, & Terblanche, 2011;Pintor, Schwarzkopf, & Krockenberger, 2016;Pough, Taigen, Stewart, & Brussard, 1983), and regulation of urine and feces production (Cain, Krausman, Rosenstock, & Turner, 2006) (b) mechanisms to regulate water intake through habitat selection and drinking behavior (i.e., free-standing water intake, Davis & DeNardo, 2007), as well as foraging behavior (i.e., dietary water intake, Lillywhite, 2017), and (c) metabolic water production (Chown, 2002;Stier et al, 2017). Some species are also capable of storing water and can thus use alternative sources of water (such as the bladder of desert species, Davis & DeNardo, 2009).…”

Water restriction causes an intergenerational trade‐off and delayed mother–offspring conflict in a viviparous lizard

“…dehydration) usually results in lower locomotor performances (i.e. endurance, jumping speed) (Prates, Angilleta, Wilson, Niehaus, & Navas, 2013) and reduced activity (Davis & DeNardo, 2009;Lorenzon, Clobert, Oppliger, & John-Alder, 1999), although positive effects may also occur such as increased immune defences (Brusch & DeNardo, 2017;Moeller, Butler, & DeNardo, 2013) or a boost of antioxidant defences (Stier et al, 2017). During reproduction, water is essential for both the mother and embryos (e.g.…”