Do current hypotheses explain continental and seasonal variation in female morph frequencies of the damselfly, Nehalennia irene?

摘要: Female-limited colour polymorphism occurs in many damselfly species, where one morph resembles the male (andromorph) and other is dissimilar (gynomorph). Explanations for this phenomenon vary, but most assume that andromorphism has arisen odonates, as a response to excessive harassment. Here, we quantify extent of continental seasonal variation female frequencies widely-distributed ask whether spatiotemporal patterns andromorph frequency can be understood on basis sexual harassment theory. We sampled damselfly, Nehalennia irene (Hagen) among regions across Canada, at several sites, over reproductive season, within Central Canada. Andromorph ranged from 0 > 90% In particular, sites Western Canada had consistently high frequencies, whereas were lower variable and, Eastern still (except site) relatively invariant. For populations both population densities varied significantly time, reaching peak mid-season. As expected, covaried with estimates some cases, did not account all regions. Additional factors such genetic drift may influence edge species’ range. Future work also should test, attempt explain causation, frequency. © 2007 The Linnean Society London, Biological Journal Society, 2007, 90, 501–508.