The Biology and Behaviour of Ptinus Tectus Boie. (Coleoptera, Ptinidae), a Pest of Stored Products

Abstract

In alternating light and darkness at 25° C., Ptinus tectus shows a diurnal rhythm of locomotory activity with maximum activity occurring in the dark period. The rhythm is continued for a few days in continuous light. In continuous light, no inherent 24 hr. rhythm is apparent, but in subsequent alternating light and darkness, within 1 day, activity becomes practically confined to the dark period. The rhythm can be reversed by reversing the hours of light and darkness and the reversed rhythm is similarly continued in continuous light. In conditions of alternating light and darkness with fluctuating temperature (10-20° C. with low temperature in the dark periods) Ptinus shows greater activity than at 25° C., and maximum activity occurs in the cold, dark period. In constant light and daily fluctuating temperature (17-23° C.), the period of greatest activity occurs when the temperature is falling. After transfer to constant temperature, this period still occurs at the same time of day for a few days.