Control of Diurnal Rhythms of Activity in Periplaneta americana L.

Circadian Rhythms in Insects

“…Detailed studies have been made, for example, of the activity rhythms of several species of cockroach [2][3][4][5][6][7][8][9][10][11], the cricket Gryllus [12] and the beetle Tenebrio [13]. In all these insects active walking begins close to the start of the dark phase in LD 12 : 12, when the temperature is held constant, although even between individuals of the same species there may be considerable variation in the phase-relationship to the light-off signal.…”

“…Activity records of cockroaches show differences between adult males and females [3,17]. but to what extent these differences are related to reproductive activity is not yet entirely clear.…”

“…The effect of feeding on activity rhythm of the cockroach P. americana has been studied by Harker [3] and Lipton & Sutherland [17]. The latter measured the feeding activity by recording the movement of a pendulum on which the food was suspended; use of this method reveals a feeding rhythm which is very similar to the locomotor rhythm in terms of time of onset and period length, in its ability to be reset by a change in the LD cycle, and most important, in its persistence in DD.…”

“…Unfortunately these authors did not test the effect of giving food at only one time of day during DD to establish whether a phase-shift could be effected, so that the question of whether the presence of food can act as a Zeitgeber is still an open one. In the earlier experiments [3] an attempt was made to answer this question by restricting food availability to a few hours during the light phase of an LD cycle. Although the insect became active in the presence of food the normal activity rhythm continued, and the activity during the light phase appears to be only an immediate response to the presence of food; when food was not presented on any particular day there was no increase in activity at that time of day.…”

“…To verify the assumption that an endocrine system is involved in the control of activity, the main endocrine systems were removed by beheading the insect; cockroaches can still walk after this operation, but are arrhythmic [3], as has since been confirmed by a number of authors [8,Ill,112,113,114]. Transplantation of the brain, corpora cardiaca, corpora allata, or thoracic or abdominal ganglia together with their associated neurohaemal organs, from rhythmic donors into headless cockroaches is not followed by any rhythmic activity [3,5,8,115].…”