SHORT-TERM RESPONSES OF BENTHIC AND EMERGING INSECTS TO DAMSELFLY PREDATION
Evidence from fishless communities suggests that invertebrate predators can strongly impact invertebrate abundance and community structure. However, there is little research on the impact on emergence, despite recent evidence that predation can have different effects on benthic versus emerging insects. We measured the response of benthic and emerging insects to a density gradient (0-10 individuals/m2) of the invertebrate predator, Enallagma civile, over 28 days in outdoor mesocosms. Preliminary analysis showed a negative relationship between the density of damselflies and insect emergence abundance (primarily Chironomidae). In contrast, we found no evidence of a relationship between damselfly density and benthic insect abundance. However, the slopes of these effects had broad confidence intervals, and we found no evidence that they differed in the strength of effect between emerging and benthic prey. Moreover, after week one any predator control by damselflies disappeared, likely due to other invertebrate predators (e.g. beetles and dragonflies) colonizing the pools, or to delayed emergence in pools with high densities of damselflies.
Lauren Henning (Primary Presenter/Author), University of South Dakota, email@example.com;
Jeff Wesner ( Co-Presenter/Co-Author), University of South Dakota, Jeff.Wesner@usd.edu;