Limited sex differences in plastic responses suggest evolutionary
conservatism of thermal reaction norms: a meta-analysis in insects
Abstract
Temperature has a profound effect on the growth and development of
ectothermic animals. However, the extent to which ecologically-driven
selection pressures can adjust thermal plastic responses in growth
schedules is not well understood. Comparing such responses between sexes
provides a promising but underexploited approach to evaluating the
evolvability of thermal reaction norms: males and females share largely
the same genes and immature environments but experience different
ecological selection pressures. In this study, we performed a
meta-analysis of sex-specific thermal responses in insect development
times. We show that sex-specific responses of development times to
temperature variation are broadly similar. Moreover, sex differences in
thermal plasticity are considerably less pronounced than sex differences
in plastic responses induced by variations in larval diet. Our results
point at the existence of substantial constraints on the evolvability of
thermal reaction norms in insects, an essential aspect to consider in
predicting evolutionary responses to climate warming.