Feeding rhythms in the American cockroach, Periplaneta americana

Abstract

Although much attention has been given to the biological rhythm of activity of the American cockroach, no previous studies on its feeding rhythms have been made. Feeding rhythms were determined with a trophometer, the design and operation of which was based on a food-bearing pendulum whose movement opened and closed an electrical circuit. A total of 64 adult male cockroaches were examined in 12 hr light 12 hr dark for entrained feeding rhythms. Of these individuals, 89·0 per cent exhibited rhythms, 6·3 per cent demonstrated patterns, and 4·7 per cent displayed apparent random feeding activity. The entrained feeding rhythms closely resembled entrained activity rhythms with the onset of feeding occurring soon after the onset of darkness. Some individuals exhibited multiple nocturnal feedings and feeding in the light phase, which was influenced by the presence of a retreat. Of 37 adult males examined for free-running feeding rhythms in total darkness 21·6 per cent exhibited rhythms, 48·6 per cent demonstrated patterns, and 29·8 per cent displayed apparent random feeding. Since the feeding and activity rhythms or patterns were similar to each other with respect to time of onset and percentages of individuals possessing them, the possibility of their interrelationship has been considered.