Document Type

Thesis

Degree

Master of Science

Major

Biology, Ecology

Date of Defense

4-15-2025

Graduate Advisor

Nathan Muchhala, Ph.D.

Committee

Aimee Dunlap, Ph.D.

Sara Miller, Ph.D.

Abstract

Neotropical nectar bats in cloud forest ecosystems must navigate and forage in dark, complex landscapes containing an incredible diversity of flowering plants. Despite these challenges, nectar bats are extremely successful at exploiting nectar resources from plants. Much of the sensory ecology behind these bat-plant interactions has been investigated and we know from previous studies that echolocation and olfaction are critical sensory modalities to nectar bats. Echo-acoustically conspicuous floral and vegetative structures as well as sulfur-containing volatile compounds function as signals, allowing bats to sense plants. However, not all plants exhibit conspicuous echo-acoustic and/or olfactory characteristics. Furthermore, many neotropical bat-pollinated plants exhibit pale/light coloration which could act as a visual signal to nectar bats. Still, the use of vision by foraging nectar bats has seldom been investigated and there is currently no behavioral evidence to suggest whether nectar bats use vision to detect flowers. In Chapter 1, I investigate how Anoura caudifer, a specialist nectarivore, uses vision and echolocation to detect and discriminate between flowers exhibiting different combinations of visual and echo-acoustic cues. I also explore how environmental light (above the range of natural moonlight) influences the sensory modalities that bats employ to aid foraging. The results from this study did not indicate that bats were using achromatic floral cues to discriminate between different flowers. However, we did find evidence that when light was available, bats used vision to detect flowers and visit them indiscriminately. Furthermore, bats only successfully used echo-acoustic cues when no light was present. In Chapter 2, I investigate how Glossophaga soricina, a dietary generalist, uses achromatic visual cues to detect flowers under natural moonlight conditions. The results showed that bats found flowers more quickly when they were presented against a highly contrasting background, indicating that bats were successful at using achromatic contrast to detect flowers. These studies provide evidence that nectar bats can use vision in different contexts to aid foraging. Finally, both studies support the need for further research in this, still largely unexplored, area of nectar bat sensory ecology.

Download

Share

COinS