Published online by Cambridge University Press: 01 February 2009
The life cycle of Tanytarsus debilis in two trout-ponds at Mirwart (Belgian Ardennes) has been investigated. The maincharacteristics were deduced from an analysis of the larval population dynamics. Photoperiod and temperature appearto determine the annual pattern. T. debilis is a spring and summer species and is trivoltine at Mirwart. Special attentionis given to the synchronizing effects of diapause phenomena on the emergences and on the larval growth periods. Theliterature data, exclusively on adults, have been reinterpreted.