Living on the edge: Habitat and host-plant selection in the butterfly Lycaena tityrus (Lepidoptera: Lycaenidae) close to its northern range limit

Abstract

We here investigate habitat preferences and its variation between the sexes as well as oviposidon site selection in a population of the Copper butterfly Lycaena tityrus in North-East Germany. Within a continuous habitat, butterflies preferred locations characterized by a higher abundance of nectar plants and a higher proportion of bare ground than found at random, stressing the pivotal importance of adult income and favourable microclimatic conditions. No differences in habitat selection could be detected between males and females, indicating a lack of mutual interference e.g. through male harassment, which is attributed to the relatively low abundance of butterflies in the study area. Females preferentially selected the lowest parts of relatively small (= young) host- plants, growing within relatively low vegetation or in the vicinity of bare ground, for oviposidon. Thus, females seem to select high-quality plants and deposit their eggs in the warmest microhabitats available. We suggest that selecting warm microhabitats is an important adaptation for the species’ survival under limiting climatic conditions, which is the case for the population studied here being found close to the species’ northern distribution limit.