The life history of Perla bipunctata Pictet, 1833 (Plecoptera: Perlidae) in the upper River Liffey, Ireland

Abstract

Perla bipunctata is the most common species of Perlidae in Ireland occurring in fast flowing, clean rivers and small streams. Although a common component of freshwater biological studies, little is known about the autecology of this stonefly. Monthly kick and Surber samples were taken over a 1-year period in the upper reaches of the River Liffey (4th order) to determine the life history of larvae. Perla bipunctata has a merovoltine life cycle taking no less than three years to complete the immature stages. Life history plots suggest two periods of egg hatching, followed by two separate cohorts developing over different lengths of time. Mature larvae from both cohorts synchronise and emerge as adults over a short period in early summer. The merovoltine life cycles of long lived invertebrates like P. bipunctata emphasise the importance of such species in reflecting the ecological quality of freshwaters over a long period of time.