Degree Name

MS (Master of Science)



Date of Award


Committee Chair or Co-Chairs

Thomas C Jones

Committee Members

Darrell Moore, Jessica Petko, Richard Carter


Circadian rhythms are often tightly confined around a mean of 24 hours with little variation in traditional model organisms in the absence of environmental time cues. Some spider species fall well outside this normal range with mean periods of 18 hours and variation around these means of 6 hours or more. This extreme variation in circadian rhythm is not well-understood and is the focus of the current study. Using Parasteatoda tepidariorum as a model organism, we investigated whether variation in eight circadian parameters could be explained by genetic variability, environmental conditions, or an endogenous feature of the circadian system of P. tepidariorum. No significant correlation was found between mother spiders and their offspring for all circadian parameters, nor was a significant difference found among groups exposed to different environmental conditions. We conclude that circadian variation seen in P. tepidariorum is likely a result of an innate circadian feature such as relaxed selection for a precise, 24-hour circadian rhythm.

Document Type

Thesis - embargo


Copyright by the authors.

Available for download on Sunday, September 15, 2024