Olingos do eat insects: Records of nocturnal mammals preying on arthropods in arboreal live-capture traps

The natural history of arboreal tropical mammals is poorly known, especially nocturnal species, because they are difficult to find. Most observations in the wild come from congregations at fruiting trees, but the extent to which they eat items other than fruit is not known. Here we report the first recorded insectivore behavior of eastern lowland olingos (Bassaricyon alleni) in the wild, confirming that insects are part of their diet. We also report Orthoptera and Lepidoptera as part of the diet of brown-eared wooly opossums (Caluromys lanatus) and mouse opossums (Marmosa sp.). We used camera traps to record the behavior of animals attracted to different baits as part of a program of pre-baiting arboreal live-capture traps in Amazonian Peru. We recorded 4 predatory events of olingos, 11 of wooly opossums, and 3 of mouse opossums catching and eating Orthoptera, Lepidoptera, and possibly other arthropods. These observations confirm that olingos eat insects, as well as fruits, and add information to the known omnivore diet of arboreal opossums and possible niche differences with sympatric species like the kinkajou (Potos flavus). We suggest more detailed diet studies through collection of feces or isotopic analysis should be used to determine the relative importance of these food items, and thus the ecological roles they play in neotropical forests.