Abstract
A running wheel type actograph for recording the locomotor activity of two species of Periplaneta cockroaches was assembled. Two types of actographs equipped with different rotatory wheels, a commercially available light weight polyvinyl chloride cup (cup type) and a cage with wood frame covered with polyethylene net (cage type) were assembled. Both types were able to record the activity of the cockroaches for three to four months continuously. The cup type had some problems in stability but could record the locomotor activity clearly, whereas the cage type was superior to the former in stability. The free-running periods of P. fuliginosa and P. americana were determined with these devices;τDD and τLL (90-110lx) were 23hr 38min and 24hr 19min in P. fuliginosa, and 23hr 59min and 24hr 12min in P. americana at 25°C, respectively. The rhythm of P. fuliginosa under LD conditions was frequently biphasic. The rhythm of P. americana showed smaller variations than that of P. fuliginosa.
