First records of rodent-infesting Cuterebra bot flies parasitizing raccoons (Procyon lotor) in North America

Larvae of Cuterebra spp. bot flies are specialized parasites of native species of either Rodentia (e.g., mice, rats, and tree squirrels) or Lagomorpha (e.g., rabbits and hares) in the Americas. However, they also infest other native and introduced wildlife, domestic animals, and humans, but which Cuterebra species parasitize these "atypical" hosts has seldom been determined, largely because the larvae are difficult to identify to species without first rearing them to adults. Here, we describe 2 Cuterebra spp. larvae removed from raccoons, Procyon lotor (Carnivora), in Washington (WA larva) and Florida (FL larva). These specimens belong to rodent-infesting species, which possess flattened, multipoint cuticular platelets in contrast to the typically single-pointed, spinelike platelets of lagomorph-infesting species. Based on the number and shape of points on these platelets, and the infestation dates and locations, we tentatively identify the species involved as Cuterebra grisea (WA larva) and C. fontinella (FL larva), which typically parasitize Peromyscus spp. mice. Uncertainty about these species' assignments arises from a lack of information on intraspecific variation in larval characteristics and the apparent lack of larval descriptions for 2 of the 7 Cuterebra species most likely to have parasitized these animals. This report seems to be the first published documentation of raccoons infested by larvae of Cuterebra spp. for the west and Gulf coasts of North America, and of rodent-infesting Cuterebra species parasitizing a species of carnivore.