Wing and body size polymorphism in populations of the stoneflyArcynopteryx dichroaMcL. (Plecoptera: Perlodidae) in the Ural Mountains, Russia

Specimens from five Arcynopteryx dichroa (McL.) populations were examined to study wing length and body size at different latitudes and altitudes. In northern Europe, female A. dichroa are usually long winged, while males are short winged. During the past 20 years, only two short-winged populations have been found, in a nameless lake, herein called Lake Ozernoe, and in Bolshaya Lagorta Lake, in Russia's Ural Mountains. In the isolated population of Ozernoe Lake (850 m a.s.l.), both sexes were micropterous. In Bolshaya Lagorta Lake (380 m a.s.l.), females were brachypterous. However, at a higher altitude (560 and 760 m a.s.l.), a population was found with macropterous females. Specimens of both short-winged populations had smaller body length than long-winged populations. Our findings give limited support to the idea that stonefly wings are reduced with altitude and latitude and more support to the supposition that small wing size is associated with population isolation resulting from lengthy geological isolation