Stress and parasitism of white-footed mice (Peromyscus leucopus) in dry and floodplain environments

Abstract

We hypothesized that flooding represents an environmental stressor that might affect the corticosterone levels, parasite prevalence, and life history of small mammals living in floodplain environments. We compared populations of white-footed mice ( Peromyscus leucopus (Rafinesque, 1818)) on floodplains and dry areas. We found more males on floodplains (p = 0.008) and more females on dry areas (p = 0.005). There were no differences in mass (p > 0.05) or intestinal parasite prevalence (p = 0.665) between dry and floodplain habitats, but bot fly larvae were significantly more prevalent in males living on floodplains (p = 0.043). Floodplain animals had significantly higher levels of corticosterone than dry-area animals in fall, and lower levels in summer (F[1,20] = 4.483, p = 0.047). In addition, we found that animals with intestinal parasites had higher levels of corticosterone than those that were without parasites (p = 0.014) or that harbored bot fly larvae (p = 0.001). Floodplains seem to be harsher environments than dry areas, but this may be a result of differences in habitat rather than a direct result of flooding.