Parasitoid genetic diversity provides high parasitism rates that decline
over generations.
Abstract
Species diversity of consumers is known to promote high attack rates
when species differ in their traits and the resources they use. Yet,
despite considerable work on the role of species diversity, we lack
information on how genetic diversity at different trophic levels affects
rates of ecosystem processes such as trophic interactions. Here, we
assess whether the available genetic diversity in three trophic levels
influences parasitism rates, both within and across generations. We used
experimental population bottlenecks to create a gradient of decreasing
genetic diversity of hosts and parasitoids, and measured rates of
parasitism, host resistance to parasitism, and host survival over 11
host generations. Less-inbred parasitoid populations exerted higher
parasitism rates (analogous to known effects of species diversity),
however, this effect became weaker over time. We conclude that genetic
diversity can have short-term ecological impacts in trophic systems,
which can be altered in the long term by evolutionary processes.