On the biology of two high mountain populations of stoneflies (Plecoptera, Perlodidae) in the southern Iberian Peninsula

摘要

The life history of two species of Perlodidae stoneflies, Perlodes microcephalus (Pictet, 1833) and Isoperla nevada Aubert, 1952, are studied in a high mountain stream of the Sierra Nevada (Granada, Spain). Both species show a univoltine life cycle. The nymphal development of P. microcephalus occurs mainly in summer and autumn, and adults emerge at the end of spring. The embryonic development period is short, taking only two months. I. nevada develops and grows mainly during the summer, but the embryonic development period is even shorter. Despite both species having a relatively similar nymphal development period, P. microcephalus reaches a considerably larger size than I. nevada. The two taxa behave as predators, but P. microcephalus exhibits a wider prey spectrum. Thus, although I. nevada is more abundant in the studied stream, P. microcephalus appears to play a more important role as top predator.