Increased prevalence of bot flies (Cuterebra fontinella) on white-footed mice (Peromyscus leucopus) near forest edges

Abstract

Several studies have suggested that forest edge is preferred habitat for white-footed mice (Peromyscus leucopus). Because previous research has shown that parasitism by bot flies (Cuterebra fontinella) is higher in open areas than in woodlands, lower rates of infestation at woodland edges could partly explain the greater preference for woodland edges by the mice. We recorded the prevalence and load of bot fly larvae in mice trapped along edge-to-interior gradients in four forested areas in east-central Illinois. At all sites the prevalence of bot flies (the proportion of infected adult mice) was greatest near the edge (less than 50 m from the woodland margin), which should reduce, not improve, the quality of edge microhabitats. Mating bot flies tend to congregate in open areas, and the higher prevalence of parasitism by bot flies near the forest edge may reflect the greater penetration of light there than in the interior.