Sex-specific effects of developmental density on life history and age-dependent flight traits

The environment organisms experience during development can have effects which carry over into their adult lives. These developmental environments may not only affect adult traits at a given point in time, but also how these traits change with age. Generally, stressful developmental environments can lead to sub-optimal adult fitness traits and a faster deterioration of these traits with age. But whether these environments affect how performance traits change with age or whether they affect males and females differently lacks evidence. Here, we test the sex-specific effects of crowding during development on life history traits such as lifespan, fecundity, age-dependent survival, and reproductive senescence, as well as flight performance traits, in the seed beetle-. We show that although developmental crowding has no effect on flight performance of either sex, on male adult lifespan, or on female age-dependant survival, it is detrimental to female lifespan and fecundity, as well as female age-dependent reproduction. Additionally, we show that flight traits can change with age and differ between males and females, which may be reflective of sex-specific life-histories and behaviour. Our study has implications for understanding how developmental environments affect life history and behavioural strategies of both males and females.