Movement patterns ofRhyssomatus lineaticollisSay (Coleoptera: Curculionidae) within and amongAsclepias syriaca(Asclepiadaceae) patches in a fragmented landscape

Abstract

Abstract. 1. Dispersal capabilities of organisms are critical in determining the landscape population structure of species as well as their likelihood of survival in fragmented landscapes. Using mark–recapture techniques on the monophagous weevilRhyssomatus lineaticollisSay (Curculionidae), within‐ and between‐patch dispersal capabilities, landscape level population structure, and the role of beetle density and host patch characteristics in setting distances, amounts, and timing of dispersal were studied.2. The data indicate thatR. lineaticollisis sedentary, with 50% of recaptured beetles moving < 1 m and the maximum distance moved < 1 km. Within‐ and between‐patch movement of beetles was unrelated to host plant patch characteristics and beetle densities.3. Despite limited dispersal,R. lineaticollisprobably functions as a patchy population in east‐central Iowa, U.S.A. because dispersals between patches are common and because all host patches surveyed contained this herbivore, indicating a lack of suitable vacant patches, a prerequisite for metapopulation structure.4. Between‐patch distances are well within the dispersal capabilities ofR. lineaticollis, although this may be the result of an increase in the density of patches of its host,Asclepias syriaca, in the landscape over the last 150 years as a result of human disturbance and this species' weedy habit.5. Metapopulation structure in monophagous prairie herbivores may be most likely in species whose non‐weedy host plants form highly predictable resources in space and time, but which are now widely scattered in habitat fragments.