Spatial learning overshadows learning odors and sounds in both predatory and frugivorous bats

To forage efficiently, animals should selectively attend to and remember
the cues of food that best predict future meals. One hypothesis is that
animals with different foraging strategies should vary in their reliance
on spatial versus feature cues. Specifically, animals that store food in
dispersed caches or that feed on spatially stable food, like fruit or
flowers, should be relatively biased to learning a meal’s location,
whereas predators that hunt mobile prey should instead be relatively
biased towards learning feature cues such as odor or sound. Several
authors have predicted that nectar-feeding and fruit-feeding bats would
rely relatively more on spatial cues, whereas closely related predatory
bats would rely more on feature cues, yet no experiment has compared these
two foraging strategies under the same conditions. To test this
hypothesis, we compared learning in the frugivorous bat, Artibeus
jamaicensis, and the predatory bat, Lophostoma silvicolum, which hunts
katydids using acoustic cues. We trained bats to find food paired with a
unique and novel odor, sound, and location. To assess which cues each bat
had learned, we then dissociated these cues to create conflicting
information. Rather than finding that the frugivore and predator clearly
differ in their relative reliance on spatial versus feature cues, we found
that both species used spatial cues over sounds or odors in subsequent
foraging decisions. We interpret these results alongside past findings on
how foraging animals use spatial cues versus feature cues and explore why
spatial cues may be fundamentally more rich, salient, or memorable.