Female mosquitoes disperse further when they develop under predation risk

Predation is one of the strongest selective forces in nature. Organisms characterized by a complex life cycle, undergoing an ontogenetic niche shift, can reduce predation risk on natal stages by metamorphosing earlier. Yet, this antipredatory response may incur numerous life-history-related costs. Interestingly, the consequence of larval predation risk on adult dispersal, a key trait dictating the persistence of spatially structured populations, is largely understudied. Here, we explored the effect of larval predation risk on the life-history and dispersal characteristics of female adults in the mosquito Culex pipiens. As predicted, mosquito larvae reared in the presence of a caged larvivorous-fish metamorphosed earlier, while also suffering from reduced survival. Despite this reduction in development time, the body size of emerging females was larger, implying that more resources were allocated to increase the growth rate, probably at the expense of reduced maintenance and storage. This shift in energy allocation translated into decreased pupa and adult survival. Remarkably, the respective dispersal distance of these larger bodied females was greater. We suggest that the increase in dispersal distance allows these females to cover larger areas, while searching for oviposition sites that are safer than their natal aquatic habitat. Exploring the effects of larval conditions on adult dispersal is central for understanding the distribution of organisms with a complex life cycle in spatially heterogeneous environments, and specifically for disease transmission by mosquitoes.