Matching larval and adult thermal environments: Is there evidence for adaptive plasticity in the mosquito Aedes albopictus Skuse?

The effects of temperature on ectotherm development are generally well known: hotter temperatures result in faster development and smaller adult size. The effects of nutrient limitation on development have also been well investigated, with higher nutrients usually resulting in faster development and larger adult size.  As adult size is critical in determining fitness (larger organisms are more fecund and often have higher survival), resolving the impact of both temperature and nutrient availability on ectotherm development can have important implications for population dynamics of pest insects.  Furthermore, recent work on mosquito vectors of disease has suggested that whether adult size is determined by temperature or nutrients may have qualitatively different outcomes, demonstrated by differences in allometry and response to challenge with pathogens.  These studies also suggest that response to temperature may show adaptive plasticity.  To test whether the mosquito Aedes albopictus has a plastic and adaptive response to temperature, we conducted a controlled growth experiment at five temperatures, generating adult mosquitoes of various sizes.  We then examined adult longevity of those mosquitoes in the temperatures they were raised in versus the other four rearing temperatures.  Increased longevity in temperatures similar to rearing temperatures relative to other temperatures would provide evidence for adaptive plasticity in adult longetivty.  While we found some significant effects of rearing temperature on survival at various adult temperatures, the patterns suggest mosquitoes from moderate temperatures survived the longest, and there was little support for an adaptive plastic response.  A more sensitive test, such as fecundity or male mating success, may provide support for an adaptive explanation of the response to temperature in future studies.