Ecology of Botfly Parasitism in White-Footed Mice (Peromyscus leucopus)

Abstract

White-footed mice (Peromyscus leucopus) are an abundant species in eastern deciduous forests. The objective of this study was to examine the ecology of botfly parasitism in a white footed mouse population in the Brockport Woods, Brockport, NY. I analyzed data collected by live trapping in May and September from 1993 to 2009. Males and females exhibited similar levels of botfly infestation. When a greater percentage of mice was infected with botflies, there was a significant increase in average body mass. I also found that as fall trap success increased, the proportion of mice with botflies decreased, but the number of infected mice remained relatively constant over time. This may be due to the fluctuation of P. leucopus populations, which is characterized by rapid increases and sudden collapses, so there may not be enough botflies to take advantage of all the available hosts at high densities. Botfly infection did not have an impact on overwinter survival. Lastly, spring abundance was most affected by trap success in the previous fall and two weather variables; spring abundance increased when fall trap success and mean January temperature increased and when total January snowfall decreased. These three variables, however, did not explain all of the observed variability in abundance. Population fluctuations in P. leucopus are complex, so future studies should look at other factors that could be responsible for driving abundance of this species.