Intra-patch movement in the Sinai Baton Blue butterfly: influence of micro-habitat and individual characteristics

Abstract

Dispersal is a key process in metapopulation biology. The transfer of individuals among patches of suitable habitat has been widely studied, and rates of movement and the factors influencing these investigated. However, relatively few metapopulation studies have examined movement of individuals within a patch of habitat, and none of these have related intra-patch movement to inter-patch movement (dispersal). The intra-patch movement of a narrowly endemic butterfly Pseudophilotes sinaicus (Lycaenidae) that exists in a metapopulation structure was studied. It was found to be extremely sedentary, rarely moving more than 40 m in or between days, and occupying a very small area during its residency of the study patch. Its level of movement (distance between sightings) and the factors affecting this depended on its sex, and was primarily determined by the density of conspecifics in its immediate vicinity. Other factors also influenced movement, notably the phenology and size of hostplants in an individual’s immediate vicinity. Responding to these variables in a predictable way can be regarded as strategies enabling the butterfly to locate mates, food, and oviposition sites, and to escape resource depletion, and intraspecific competitors. These behavioural patterns are similar to mechanisms involved in dispersal of individuals among patches of habitat in fragmented landscapes.