Hydroregulation in a tropical dry-skinned ectotherm

Abstract

While temperature effects on species' vulnerability to climate change are well studied, desiccation effects receive comparatively little attention. In addition, we poorly understand the capacity of ectotherms, and especially reptiles, to control water loss rates behaviourally by selecting suitable microhabitats. This study examined water loss rates and behavioural hydroregulation in the tropical rainforest skink Carlia rubrigularis to assess whether this dry-skinned ectotherm actively avoids desiccation and whether trade-offs occur between desiccation avoidance and selection of optimal temperatures, as previously shown in amphibians. Higher temperatures elicited humid refuge choice despite placing individuals in suboptimal thermal conditions, as indicated by preferred substrate temperatures. This finding emphasizes the importance of water loss even for taxa traditionally assumed to be highly desiccation resistant, and highlights this factor's potential influence on vulnerability to climate change by limiting activity times or by restricting individuals to thermally suboptimal microhabitats.

Water restriction induces behavioral fight but impairs thermoregulation in a dry‐skinned ectotherm

“…cool shelters, which are suboptimal for thermoregulation but, on average, half less desiccating than warm ones. This shift suggests that conditions of water restriction can trigger hydroregulation strategies critical for the maintenance of water balance at the expanse of thermoregulation strategies, as suggested by Pintor et al (2016). In natural conditions, we suspect that ecological responses to drought and water restriction will critically depend on the presence and distribution of cold and wet shelters or vegetation in the lizards' habitat (Pirtle et al 2019).…”

“…In the last two decades, a growing number of ecological studies investigated how changes in thermal quality of the environment (Row and Blouin‐Demers , Sears et al ), food availability (Manenti et al , Long et al ), and predation pressures (McGhee et al ) cause shifts in individual behavior that contribute to ecological responses to environmental changes. In comparison, fewer studies have investigated behavioral responses of terrestrial animals to changes in water availability, especially in ectotherms (Pintor et al , Pirtle et al ). The behavioral responses allowing organisms to control water inputs and losses can be viewed as components of the hydroregulation behavior (Pintor et al , Pirtle et al ).…”

“…In comparison, fewer studies have investigated behavioral responses of terrestrial animals to changes in water availability, especially in ectotherms (Pintor et al , Pirtle et al ). The behavioral responses allowing organisms to control water inputs and losses can be viewed as components of the hydroregulation behavior (Pintor et al , Pirtle et al ). Analogous to behavioral thermoregulation (Angilletta ), behavioral hydroregulation must be shaped by a balance between benefits (e.g.…”

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

“…There is indeed great scope to improve our understanding of the behavioral responses of ectotherms to variation in water availability and hydric conditions relative to thermal conditions, and to disentangle temperature and water effects on behavior (Kearney et al, 2018;Pintor et al, 2016;Rozen-Rechels et al, 2018). There is indeed great scope to improve our understanding of the behavioral responses of ectotherms to variation in water availability and hydric conditions relative to thermal conditions, and to disentangle temperature and water effects on behavior (Kearney et al, 2018;Pintor et al, 2016;Rozen-Rechels et al, 2018).…”

“…There is indeed great scope to improve our understanding of the behavioral responses of ectotherms to variation in water availability and hydric conditions relative to thermal conditions, and to disentangle temperature and water effects on behavior (Kearney et al, 2018;Pintor et al, 2016;Rozen-Rechels et al, 2018). Laboratory experiments with shuttle boxes or contrasted microhabitats (Pintor et al, 2016) and field studies of individual movements in habitat landscapes (Bartelt et al, 2010;Sears et al, 2016) will be crucial to make significant progress in this direction and to quantify the potential of behavioral traits to buffer environmental change effects. Laboratory experiments with shuttle boxes or contrasted microhabitats (Pintor et al, 2016) and field studies of individual movements in habitat landscapes (Bartelt et al, 2010;Sears et al, 2016) will be crucial to make significant progress in this direction and to quantify the potential of behavioral traits to buffer environmental change effects.…”