Date of Award
2024
Degree Type
Thesis
Degree Name
Master of Arts (MA)
Department
Biology
First Advisor
Dr. Carl D Anthony
Abstract
The novel biofluorescent glands of the Eastern Red-backed Salamander (Plethodon cinereus), have been shown to be sexually dimorphic where males have larger and greater numbers of glands than females. Interestingly, a seasonal pattern of increased numbers of fluorescent glands, which mirrors the peak in testosterone levels, has been described. Currently, the function and regulation of the fluorescent glands is unknown. I predicted that the glands function as a form of male ornamentation used in intersexual communication, and perhaps act as an honest signal of male quality. Even though the fluorescent glands are located on the underside of the tail, there are courtship behaviors, such as cloacal nudge and tail arch, which expose the fluorescence to potential mates. A behavioral study was designed where male-female pairs interacted under two light environments where fluorescence was either visible (blue light) or obscured (red light). Light environment did not directly influence courtship behavior. However, the relationship between male fluorescence intensity and courtship behaviors was positive in blue light but a negative relationship was evident in red light. This suggests that fluorescence may function as a type of male ornamentation in sexual communication, but in its absence, females may avoid otherwise attractive males. To investigate photoperiod as an environmental cue in fluorescence regulation, male salamanders were separated into two light cycle groups, static and natural. The static group was held on the light:dark cycle of a fall day, while the natural group’s light:dark cycle was consistently updated to simulate seasonal change. I predicted that, in the natural group, fluorescence would follow the seasonal pattern, but in males kept on the static photoperiod, no such variation in fluorescence would appear. Contrary to my prediction, fluorescence differences were observed in both groups which suggests that photoperiod alone does not act as an environmental cue in fluorescence regulation.
Recommended Citation
Moody-Wynn, Sam C., "DO THE SEXUALLY DIMORPHIC BIOFLUORESCENT GLANDS OF PLETHODON CINEREUS FUNCTION IN MATE CHOICE AND ARE THEY SEASONALLY REGULATED BY PHOTOPERIOD?" (2024). Masters Theses. 69.
https://collected.jcu.edu/masterstheses/69
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