Graduation Year

2025

Document Type

Open Access Senior Thesis

Degree Name

Bachelor of Arts

Department

Organismal Biology

Reader 1

Dr. Robert Brodman

Reader 2

Dr. Marion Preest

Terms of Use & License Information

Terms of Use for work posted in Scholarship@Claremont.

Rights Information

© 2024 Faben H Tesfazion

Abstract

Amphibians are at disproportionately higher risks of extinction than all other vertebrate classes, and a major causing factor is invasive predation. The American bullfrog (Lithobates catesbeianus), native to Eastern North America, is a notorious invasive species which preys on native Sierran treefrogs (Pseudacris sierra) in Northern and Central California. These treefrogs have yet to be placed on any Special Animals List, suggesting the presence of adopted behaviors against predation. Past studies have documented the importance of chemical sensing in anuran tadpoles as predator detection tools. This study tests if Sierran treefrog tadpoles can recognize invasive chemical cues by measuring antipredator behaviors, defined as decreased activity and increased crouching, in tadpoles against cues from invasive bullfrogs. Responses are compared to those displayed against a native predator: dragonfly nymphs (Suborder Anisoptera). It also tests whether these behaviors are exacerbated by the absence of nearby conspecifics, as a predator threat may be magnified amongst lone tadpoles. Our results show a significant decrease in activity and a significant increase in crouching behavior in tadpoles presented with bullfrog chemical cues, which are indicators of antipredator behaviors being utilized against this non-native threat. We also found that, while there was a significant decrease in activity levels in the presence of dragonfly nymph chemical cues, there was no significant crouching behavior under these conditions, which may be explained by an adaptation to dragonfly nymph hunting behavior. Finally, we found a significant decrease in activity level in tadpole groups compared to individuals, which may indicate conspecific communication.

Download

Share

COinS