(full paper is archived in the Miller Library)
Title: Exogenous and endogenous factors determining the activity patterns of the sand beach isopod Alloniscus perconvexus
Student Author(s): Pratt, Stephen R.
Faculty Advisor(s): Gilmartin, Malvern
Location: Final Papers Biology 175H
Date: June 1973
Abstract: 1. Field studies have indicated that Alloniscus perconvexus, the sand beach isopod, exhibits a definite pattern of nocturnal activity, with peak activity between 2200 and 0200. 2. Laboratory studies indicated that A. perconvexus demonstrates a positive phototropic response when threatened by desiccation. 3. Strong evidence was found for the existence of an endogenous rhythm in A. perconvexus which is in synchrony with the natural light-dark cycle. This rhythm seems to determine the activity patterns of the animal. This is a powerful rhythm, for after 7 days of entrainment to a reversed light regime, the activity pattern of a population of A. perconvexus shift withing 3 days to that pattern assocaited with a normal light cycle once the population was placed into constant darkness.