Density-dependent dispersal in biological control agents: a reflexion on the side-effects of mass-rearing conditions

Description

High-density rearing conditions for the mass-production of biological control agents are known to affect individual quality and performance. However, complex phenotypic traits like dispersal behaviour and their response to rearing conditions are rarely investigated, although they are likely to affect directly biocontrol efficiency in the field. In this study, we develop an original experimental design to evaluate two complementary components of dispersal behaviour in Trichogramma. Then, we investigate how these components respond to variations in rearing density, and their correlation with traits related to parasitoid fitness. We find that under high-density conditions, a large proportion of individuals display reduced mobility and fecundity, indicative of a lower-quality phenotype. These interactive effects between dispersal performance and individual fitness highlight the need to develop integrative experimental designs to easily quantify complex phenotypic traits related to the field performance of biological control agents

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