Fruiting trees provide fruit and insect resources for four tropical deer species

Fruiting trees provide important fruit and seed resources for various
animal species, but rarely are they considered to be rich sources of
insects as well. During a study of seed dispersal of Trewia nudiflora
(Euphorbiaceae) using camera-traps in Nepal, we observed four tropical
deer species (Axis axis, Muntiacus vaginalis, Rusa unicolor, Axis
porcinus) foraging for insects, rather than fruits under the trees. These
herbivorous deer are proven seed dispersers of Trewia, but 8-38% of video
captures (across each species) were of insectivory, rather than frugivory.
The deer chased and consumed red cotton bugs (Dysdercus sp. family
Pyrrhocoridae), which were seed predators that hoarded Trewia seeds. It is
likely that other unidentified insect species were also consumed. Tropical
deer species are considered to be fully herbivorous, so our observations
extend their known diets and possibly indicate a seasonal requirement for
protein. These findings also highlight tri-trophic interactions among
deer, insects, and fruits that could have important implications for
seedling recruitment if seed predators are being consumed by seed
dispersers (in addition to fruit consumption).