Wing Polymorphism inCapnia bifrons(Plecoptera: Capniidae)

Abstract

In the stonefly Capnia bifrons a first description of relatively long winged, brachypterous instead of micropterous, males is given. Two neighbouring populations, one with brachypterous, the other with normal micropterous males, are compared. It appears that the brachypterous males pass through one more larval instar than the micropterous ones. Male brachypterism of Capnia bifrons in the present population probably results from genetic determination, rather than from modifying environmental factors.