Maternal investment and early thermal conditions affect performance and antipredator responses

Exposure to increased temperatures during early development can lead to
phenotypic plasticity in morphology, physiology, and behaviour across a
range of ectothermic animals. In addition, maternal effects are known to
be important contributors to phenotypic variation in offspring. Whether
the two factors interact to shape offspring morphology and behaviour has
been barely explored. This is critical since climate change is expected to
impact both incubation temperature and maternal resource allocation and
stress levels. Using a fully factorial design, and Bayesian multivariate
mixed models, we explored how the manipulation of early thermal
environment and yolk-quantity in eggs affected the morphology, performance
and antipredator behaviour of two sympatric Australian skink species
(Lampropholis delicata and L. guichenoti). We found that juveniles from
the hot treatment were larger than those on the cold treatment in L.
guichenoti but not L. delicata. Using repeated behavioural measures for
individual lizards, we found an interaction between incubation temperature
and maternal investment in performance, with running speed being affected
in a species-specific way by the treatment. We predicted that changes in
performance should influence antipredator responses. In support of this
prediction, we found that maternal investment impacted antipredator
behaviour, with animals from the yolk-reduced and cold treatment resuming
activity faster after a simulated predatory attack in L. delicata.
However, the prediction was not supported in L. guichenoti. Our results
highlight the importance of exploring the multifaceted role that
environments play across generations to understand how different
anthropogenic factors will impact wildlife in the future.