COOPER, A.-S.*; COOPER, H.; COOPER, R.L.; Dept. Biol., Univ. of KY, Lexington, KY; Central Baptist Hosp., Lexington, KY; Dept. Biol., Univ. of KY, Lexington, KY: Behavioral characterization of Drosophila melanogaster larvae in relation to circadian patterns

It is well established that adult Drosophila m. show circadian patterns in movement and feeding behavior, however investigations in larval circadian patterns are lacking. Circadian cycles in adults can be entrained by exposure to light as early as the embryo stage. In addition, entrainment for a circadian cycle can be induced in larval stages. The neurons responsible for this are controlled by the larval optic nerve (Bolwig�s nerve). We postulated that circadian patterns also exists in larval stages since animals can be entrained during these instar stages. To approach this we exposed larvae to a 12:12 light (white light):dark (red light) cycle from embryo to early 3rd instar. Three paradigms were then used:(1) animals remained on a 12:12 light:dark cycle; (2) animals were exposed to 24 hours dark; and (3) animals were exposed to 24 hours light. We assessed body movement patterns, feeding intensity (i.e., mouth hook movements), and pauses/rests during the 24 hours in each paradigm as well as for 4 hours in the white light (normal cycle) after each experimental paradigm. The movements were traced by hand on to tracing paper during fast viewing of videotape records for preliminary indexing of locomotive behavior. Total time of mouth hook movements within each hour was also measured. The total rest times of periods longer than 5 minutes in which no locomotive or mouth hook movements could be observed were compiled for each hour. These experiments are still in progress but from preliminary data of body movements it appears that larval Drosophila m. show circadian patterns. We will report updated analysis on the poster. Also we have begun testing the effects of established clock gene mutations on larval Drosophila m. circadian patterns.