Cannibalism and Necrophagy Promote a Resource Loop and Benefit Larval Development in Insects of Temporary Waters

摘要

The consumption of conspecific individuals by cannibalism (i.e., the killing and eating of conspecific individuals) and necrophagy (i.e., feeding on dead individuals of the same species) has been documented in several insect species. Selective advantages have been proposed to explain the persistence of these behaviors in natural populations. In this paper, we tested the hypothesis that cannibalism and necrophagy lead to a significant resource loop within an insect cohort, allowing individual survival and development. With this aim, we performed laboratory and semi-field experiments using the tiger mosquito Aedes albopictus. Larval stages of this species develop in small aquatic habitats, such as tree holes and artificial containers. These latter are highly ephemeral habitats, where resources are often scarce and of poor quality (mainly leaf litter, wood, and vegetal detritus). We first estimated the relative rate of cannibalism and necrophagy. Then, we analyzed the effects of cannibalism and necrophagy on larval survival and adult yield. Consistent with our hypothesis, we found that conspecifics consumed about 50% of the initial cohort. Furthermore, conspecific consumption significantly increased the rate of adult emergence and larval survival, which supports that cannibalism and necrophagy can positively affect insect populations in temporary waters.