Most cited article - PubMed ID 28082616
Economic thermoregulatory response explains mismatch between thermal physiology and behaviour in newts
Many ectothermic organisms counter harsh abiotic conditions by seeking refuge in underground retreats. Variations in soil hydrothermal properties within these retreats may impact their energy budget, survival and population dynamics. This makes retreat site choice a critical yet understudied component of their strategies for coping with climate change. We used a mechanistic modelling approach to explore the implications of behavioural adjustments and seasonal acclimation of metabolic rate on retreat depth and the energy budget of ectotherms, considering both current and future climate conditions. We used a temperate amphibian, the alpine newt (Ichthyosaura alpestris), as a model species. Our simulations predict an interactive influence of different thermo- and hydroregulatory strategies on the vertical positioning of individuals in underground refuges. The adoption of a particular strategy largely determines the impact of climate change on retreat site choice. Additionally, we found that, given the behavioural thermoregulation/hydroregulation and metabolic acclimation patterns considered, behaviour within the retreat has a greater impact on ectotherm energetics than acclimation of metabolic rate under different climate change scenarios. We conclude that further empirical research aimed at determining ectotherm behavioural strategies during both surface activity and inactivity is needed to understand their population dynamics and species viability under climate change.
- Keywords
- energy budget, hydroregulation, mechanistic niche modelling, retreat site choice, thermoregulation,
- MeSH
- Acclimatization * MeSH
- Behavior, Animal physiology MeSH
- Climate Change * MeSH
- Humans MeSH
- Soil MeSH
- Temperature MeSH
- Body Temperature Regulation MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Soil MeSH
The energy costs of self-maintenance (standard metabolic rate, SMR) vary substantially among individuals within a population. Despite the importance of SMR for understanding life history strategies, ecological sources of SMR variation remain only partially understood. Stress-mediated increases in SMR are common in subordinate individuals within a population, while the direction and magnitude of the SMR shift induced by interspecific competitive interactions is largely unknown. Using laboratory experiments, we examined the influence of con- and heterospecific pairing on SMR, spontaneous activity, and somatic growth rates in the sympatrically living juvenile newts Ichthyosaura alpestris and Lissotriton vulgaris. The experimental pairing had little influence on SMR and growth rates in the smaller species, L. vulgaris. Individuals exposed to con- and heterospecific interactions were more active than individually reared newts. In the larger species, I. alpestris, heterospecific interactions induced SMR to increase beyond values of individually reared counterparts. Individuals from heterospecific pairs and larger conspecifics grew faster than did newts in other groups. The plastic shift in SMR was independent of the variation in growth rate and activity level. These results reveal a new source of individual SMR variation and potential costs of co-occurrence in ecologically similar taxa.
