Spatial organization of the clouded Apollo population (Parnassius mnemosyne) in Onega Lake Basin

Abstract

The distribution and interaction of local populations of the clouded Apollo Parnassius mnemosyne were studied on Bolshoi Klimenetskii Island (Lake Onega, Russia). Within an area of 10 km2, the butterflies occurred in 27 discrete patches—small meadows located within and on the periphery of forests. The mark-recapture results confirmed that the patches were connected by a flow of individuals. Based on exponential distribution, the local and migratory movements of the butterflies were separated, and a model describing the movement frequencies in relation to distance was proposed. The generalization of the habitats using the PCA Q-technique and isolation indices as measures of similarity between the objects in initial matrices revealed four subpopulations occupying separate plots of the area with a network of suitable habitats. According to the available data on the local movements of butterflies, an area of settlement was determined for each subpopulation, characterized by two zones: the central one (0.3 km in diameter), within which the movements of butterflies are most intensive, and the peripheral one (0.3 to 0.5 km) which is rarely visited by butterflies. Long-distance migrations between different occupied areas were recorded for 8% of marked butterflies; they included all the subpopulations. The male to female ratio among the migrants was 6: 1; the maximum distance covered by a butterfly was 2.68 km. The common opinion that the clouded Apollo is an extremely sedentary species with low migratory potentials is refuted.