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

Abstract

At 70% R.H. development of Ptinus tectus from egg laying to emergence from the cocoon is minimal at 23-25°C. and takes an average of about 62 days; at 15°C. the time taken is about 130 days. The minimum temperature at which complete development can occur is below 10°C. and the maximum is between 28 and 30°C.; considerable mortality occurs in eggs and larvae at 28°C. and the eggs require a humidity of 100% R.H. for hatching at this temperature. At 75% R.H. and above it is difficult to prevent moulds growing on the food of Ptinus. It appears that 70% R.H. is a satisfactory humidity for all developmental stages, but in air drier than this (at 25°C.) both eggs and larvae show an increased mortality and a prolonged development. The hatching of the egg, rather than embryonic development, seems to be sensitive to low humidity. Adults given food but not water live longer at 70% R.H. (27°C.) and at 90% R.H. (15°C.) than at lower humidities. At 25°C., below 70% R.H. feeding is much reduced if water to drink is not given; at 34% there is little feeding even when free water is available. Larval feeding is also reduced at low humidities. Oviposition soon ceases unless drinking water is available, at any rate at low humidities. Ptinus tectus is thus adapted to a temperate climate with a high humidity.