Genetic variation and rapid evolution within populations can shape the species interactions, which may in turn influence community dynamics. However, an interplay between dynamics of rapid evolution and ecological communities in the field has been still poorly understood. Most of studies have only addressed evolution of clonally reproducing organisms in a simple community with a few members. In this study, we conducted a field experiment testing the effects of genetic variation in willow leaf beetle (Plagiodera versirocolora) on ecological dynamics of interacting arthropod communities, and the feedback to rapid evolution in the leaf beetle.
We first performed a RAD sequencing and genome-wide association study to construct markers for tracking rapid evolution in focal traits of a non-mdoel organsism. Next, we conducted a large mesocosm experiment, inoculating leaf beetle populations. These beetles have a genetic variation in a host use trait: a specialist- and generalist type. The specialist-type exclusively feeds on new leaves of willows, while the generalist-type displays non-preferential feeding for leaf-age types. We initially manipulated leaf beetle populations in inoculation as follows: 1) specialist-type, 2) genelalist-type, and 3) mixed treatment. Initial beetle treatment significantly influenced subsequent community dynamics of arthropods on a whole tree crown. And then we detected rapid evolution of the host use trait of the leaf beetle in response to differences in arthropod community structure.