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.

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

“…Previous papers in this series (Bentley, Gunn & Ewer, 1941;Gunn & Hopf, 1942;Ewer & Ewer, 1942) have provided information about the relations between Ptinus tectus and environmental factors, particularly temperature; this paper is concerned with the temperature region in which this species tends to aggregate when placed in a temperature gradient. Determination of this preferred temperature presents certain difficulties which have been recorded by Deal (1941) in connexion with several species of beetles but, as will be seen, on the whole the results fall into place with information already obtained here about P. tectus.…”

“…It has been shown by Bentley et al (1941) that the frequency of locomotory activity of P. tectus varies with a diurnal rhythm, under suitable conditions, and that this rhythm can be controlled by controlling the times of day during which the animals are in the light. In the temperature preference experiments three groups of animals were used: rhythmless animals, which had been kept at 25 0 C. in unvarying light long enough to abolish the rhythm; day-phase animals, which were similarly kept, but in artificial light of about 25 me.…”