Lek structure and territoriality in the chryxus arctic butterfly,Oeneis chryxus (Satyridae)

Summary The territorial and mating systems of the satyrid butterfly Oeneis chryxus were studied for 3 years on individually marked populations in algonquin Provincial Park, Ontario. Males defended territories in a dry open forest clearing by means of chases and spiral flights with conspecifies. Defended areas did not contain food or oviposition sites required by females. Territories were not uniformly distributed over the study area; the highest density of territories was clustered over bare ground covered with sand and small stones rather than areas of vegetation. This pattern of distribution of territories occurred during each year of the study. The patterns of occupancy of territories showed a high degree of consistency from one day to the next, some males defending a given territory for as many as 11 consecutive days. Removal experiments showed that a surplus of non-territorial males did not exist. Vacant territories in the high-density area were absorbed by neighboring males; those in the low-density area remained empty. Male size was not correlated with territory position in the study are. Wing patterning (i.e. size of spots) differed between males occupying territories on sandy/stony versus vegetated areas. The territorial and mating systems of O. chryxus resemble lek polygyny, and are more similar to some vertebrate lek systems than to hilltopping or landmark territoriality.