Effects of population density and of presence of Gammarus pulex L. (Amphipoda) on the growth in larvae of Potamophylax cingulatus steph. (Trichoptera)

Growth rates and mortality of Potamophylax cingulatus were studied at different densities, temperatures, and food items, as well as in the presence and absence of Gammarus pulex. When alder leaves were supplied as food as well as beech leaves at 15° C, an interspecific competition was observed. The potential influence of competition in a free living population as a component in the heavy ‘natural mortality’ was discussed.