Life cycle of three stonefly species (plecoptera) from an apenninic stream (italy) with the description of the nymph of nemoura hesperiae

The life cycles of Isoperla grammatica, Amphinemura sulcicollis and Nemoura hesperiae are studied in a Northern Italy stream, sited in the Apennines. The three species show a univoltine life cycle and their development coincides approximately in the same period of the year, although the one of I. grammatica is longer. Possible egg dormancy could exist in the A. sulcicollis and N. hesperiae life cycles, but this needs to be proved. The three taxa show a spring flight period in the study area. Growth is almost constant through the life cycle, except in A. sulcicollis in which an increase is observed at the end of the development. N. hesperiae exhibits a faster growth than the other species. In addition, in this paper, the nymph of N. hesperiae is described and designed for the first time.