The effects of plant characteristics on the movement behavior of a willow flea beetle, Altica subplicata, were studied along a sand dune in northern Michigan, using mark-recapture techniques. Beetles were group-marked on each of 6 plants, and residency and subsequent colonization of plants were monitored by tagging each plant colonized by beetles, and sampling all tagged plants up to 9 days after marking. Beetles exhibited a high degree of mobility among plants, with almost half of the plants having marked beetles present on only one out of six sampling dates. Over 70% of the beetles colonized the usual host plant, Salix cordata, and the remainder occurred on 12 other plant species. Beetle residence was significantly longer on host plants than on nonhost plants and longer on plants with higher beetle densities, but was unaffected by plant height or the density of neighboring herbaceous monocots, herbaceous dicots, S. cordata, other willow plants, or other woody plants. Beetle colonization of S. cordata was significantly greater on taller plants and on plants with higher density of surrounding S. cordata and lower density of surrounding herbaceous monocots. Thus, patterns of colonization were more important than patterns of residence in influencing beetle movement and overall abundance.