Effects of developmental and adult environments on ageing

Developmental and adult environments can interact in complex ways to
influence the fitness of individuals. Most studies investigating effects
of the environment on fitness focus on environments experienced and traits
expressed at a single point in an organism’s life. However, environments
vary with time, so the effects of the environments that organisms
experience at different ages may interact to affect how traits change
throughout life. Here we test whether thermal stress experienced during
development leads individuals to cope better with thermal stress as
adults. We manipulated temperature during both development and adulthood
and measured a range of life-history traits, including senescence, in male
and female seed beetles (Callosobruchus maculatus). We found that thermal
stress during development reduced adult reproductive performance of
females. In contrast, lifespan and age-dependent mortality were affected
more by adult than developmental environments, with high adult
temperatures decreasing longevity and increasing age-dependent mortality.
Aside from an interaction between developmental and adult environments to
affect age-dependent changes in male weight, we did not find any evidence
of a beneficial acclimation response to developmental thermal stress.
Overall, our results show that effects of developmental and adult
environments can be both sex- and trait- specific, and that a full
understanding of how environments interact to affect fitness and ageing
requires the integrated study of conditions experienced during different
stages of ontogeny.