Date of Award
2025
Degree Type
Thesis
Degree Name
Master of Science (MS)
Department
Biology
First Advisor
Dr. Carl D Anthony
Abstract
Biofluorescence is increasingly recognized as a potentially important form of visual communication across a wide range of taxa, yet its ecological and behavioral function remains largely untested in many terrestrial species. In the red-backed salamander (Plethodon cinereus), fluorescence is a sexually dimorphic trait most strongly expressed in males, particularly around the cloacal region and ventral side of the tail, areas that are often displayed during territorial contests and courtship. Rival males also direct behaviors like cloacal investigation toward these fluorescent regions, suggesting a potential signaling function. Since fluorescence is often displayed during territorial contests, I hypothesized that fluorescence in male P. cinereus would serve as an honest signal of fighting ability and territory quality. This was tested using a two-part study where, in a laboratory experiment, I assessed contest outcomes and habitat choice, and a field study where I examined associations between fluorescence, body condition, and territory quality. In the lab, I predicted that more fluorescent males would win contests and occupy higher quality microhabitats, but my study design failed to provide an adequate habitat gradient to test this hypothesis. In contrast, field data offered stronger support that fluorescence is used for signaling. Fluorescence was found to be marginally associated with body condition in spring but not in fall, possibly due to the costs of elevated testosterone in this season. While no link was found between fluorescence and abiotic features of territories, fluorescence was positively associated with prey diversity and composition when seasons were combined. In spring, fluorescence correlated with high quality prey like Collembola, while in fall, fluorescence was negatively associated with energetically costly, low quality prey such as non-oribatid mites. These findings suggest that fluorescence may act as an honest signal of territory quality, suggesting that only the most fluorescent salamanders gain access to high quality territories.
Recommended Citation
Watterson, Kasey, "The role of post-cloacal gland biofluorescence in male-male communication in Plethodon cinereus" (2025). Masters Theses. 72.
https://collected.jcu.edu/masterstheses/72
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