The circadian rhythm of the dump fly was recorded using an actigraph that we produced and developed. The actigraph records insect activity by using a trigger mark system consisting of seven infrared emitters with lenses and their corresponding receptors. The receptors are connected to a Mac SE Macadios Analog to Digital converter computer. The computer records each time one of the receptors is blocked due to movement of a test organism. The data was compiled and summarized through the use of programs we developed and analyzed using Igor Pro. The endogenous cycle of the dump fly is described as are the results of entraining experiments.

Index terms: Zeitgeber, Entrainment, Free-running rhythm, Behavior

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