Variation in Prey-Specific Consumption Rates and Patterns of Field Co-Occurrence for Two Larval Predaceous Diving Beetles

摘要: Freshwater predatory insects can exert strong effects on prey, although how multiple similar predators may coexist is not well understood. Larval predaceous diving beetles are often numerically and taxonomically abundant in lentic systems, but the proximate mechanisms that explain their high abundance remain unknown. Field surveys were conducted twice June ponds Alberta, Canada to assess associations between larvae of two genera (Graphoderus, Rhantus), spatial locations, correlations with potential prey. Both common positively correlated within wetlands neither varied pond depth nor distance from edge. Laboratory trials indicated Graphoderus consumed more prey (corixids) at surface, whereas Rhantus killed benthic (chironomids) corixids an equal rate; damselflies least Predation also depth, both feeding higher rates shallowest environments compared intermediate depth. Predator–prey mostly congruent predation trials; was corixids, chironomids; uncorrelated damselflies. Reliance different microhabitats be important mechanism for maintenance dytiscid larvae.