HOST PLANT PHENOLOGY AND BUTTERFLY DISPERSAL: CAUSES AND CONSEQUENCES OF UPHILL MOVEMENT

摘要: In the Wenatchee Mountains of central Washington State, populations lycaenid butterfly Euphilotes enoptes occur patchily with their sole host plant, Eriogonum compositum (Polygonaceae). Nearly all courtship and adult feeding on inflores- cences this long-lived perennial. Furthermore, because females oviposit inflorescences larvae feed only flowers developing seeds, window opportunity for exploiting resource is narrow. I demonstrated that inflorescence phenology varied according to aspect elevation plant patches, butterflies were most likely in patches nearing full bloom. A mark-release-recapture study revealed indi- vidual can disperse far enough sample from a wide range patch phenologies, movements are apparently influenced by those phenologies. particular, an uphill bias female movement appeared be result greater emigration senescing low-elevation than phenologically delayed, high-elevation patches. Males showed no such movement. The apparent was larval densities increased fourfold over 300-m elevational gradient each two years. Differential mortality unlikely explanation variation density, as both parasitism rates frequency visitation ants, which tend larvae, did not vary elevation. To demonstrate influence behavior, manipulated flowering artificially established grid small observed encounters Inflorescences bloom received disproportionately many visits females, indicating phenological state more attractive females. Small sizes prevented me determining if due entry into number visitations per female, or both. different visited males phenology. These results suggest dispersal indeed response Thus, system, among-patch influences relative altering patterns among