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

Abstract

1. In a long temperature gradient apparatus, Ptinus tectus aggregates around two distinct temperatures, 4 and 24° C. 2. In a circular temperature alternative chamber there is no marked avoidance of low temperatures if the gradient is steep, but characteristic avoiding reactions occur if the gradient is not very steep. 3. When the stationary animals are subjected to rising or falling temperatures in the long gradient, there is a well-marked evacuation temperature at 30-33° C., but none at lower temperatures. 4. A temperature preference around 24° C. is correlated with favourable temperature for growth and other activities. The aggregation around 4° C. is the result of a failure of coordinated behaviour in a particular kind of gradient, and P. tectus is practically immobilized by cold in that temperature region.