Diversity, function and stability in parasitoid communities

The parasitoid assemblages associated with grass-feeding chalcid wasps in G reat Britain were used to examine the relationships between diversity (spec ies richness), community function (total parasitism rate) and stability (va riability in parasitism rate over time). Species-rich communities did not g enerate higher parasitism rates than species-poor communities, nor was temp oral variation of parasitism rates related to parasitoid community richness . The mechanisms underlying hypotheses linking species richness and communi ty function and stability are discussed in the light of these results. Beca use all parasitoid species represent a single functional group, a lack of c omplementarity in the ways they use their resources may explain why diversi ty is not linked to function or community stability. A second likely reason is that these parasitoid communities are under bottom-up control, thus exe rting little or no influence on total system function and variability. This is likely to be common in parasitoid communities.