| dc.description.abstract | Animals rely upon chemical cues to find critical resources for their survival and fitness, including food, shelter, and mates. Behavioral strategies for tracking odor cues are heavily dependent on differences in locomotor and sensory morphology and physiology, which vary substantially across taxa and environments. One of the biggest challenges to olfactory tracking is speed: chemical cues are inconsistent in intensity and temporal and spatial distribution. Consequently, animals engaged in olfactory searches frequently slow down and incorporate lateral movements to reconstruct the local odor structure. Olfactory tracking behaviors have been investigated in many terrestrial vertebrates, but not in flying mammals (bats). Bats are known to use olfaction for communication and foraging and offer an opportunity to evaluate current hypotheses about interactions between ecology, morphology, and behavior when localizing an odor source. In Chapter 2, I applied a phylogenetic framework to investigate whether bat nasal morphology may enhance or constrain the triangulation of odors during odor tracking. Surprisingly, I found that bats known to use odor during foraging (fruit and nectar feeders) had exceptionally narrow separation of the nostrils compared to other species, reflecting a potential trade-off between stereo-olfaction and nasal echolocation. In Chapter 3, I developed a set of behavioral assays using northern yellow-shouldered fruit bats (Sturnira parvidens), a Neotropical fruit bat, to quantify the olfactory search strategies of crawling bats. These experiments demonstrated that bats share some similarities with tracking strategies of terrestrial mammals but differ in their use of head scanning behavior during olfactory search. Finally, in Chapter 4, I used three-dimensional tracking software to characterize the flight paths of Jamaican fruit-eating bats (Artibeus jamaicensis) searching for an attractive odor source in a flight cage. These results revealed that flying bats are unlikely to use large-scale odor structure or plume information to guide them to the source. Instead, bats appeared to use a serial sampling and route-following strategy that integrated olfaction and echolocation to quickly and efficiently find the rewarded odor source. Collectively, these results show that bats displayed cognitive strategies that integrate high speeds and biosonar behaviors to optimize their olfactory searches. Understanding the role of olfactory cues in foraging decisions and search behaviors of bats may have important implications for understanding how bats use the landscape for foraging and navigation. | en |
