In vitro studies on the environmental biology of Goiodes colchici (Denny) (Mallophaga : Ischnocera) II. The effects of temperature and humidity on water loss

Abstract

Weight changes have been used to assess the effect of various conditions of temperature and humidity on the rates of water loss of pheasant body lice, G. colchici. Both living and dead animals, in 0% R.H., lose water at a low but increasing rate from 32 to 40C; above this temperature, the rate of water loss suddenly increases. Living insects lose water at half the rate of dead ones over this temperature range. At 35C and 0% R.H., all non-moulting stages lose water at a similar rate. Moulting insects lose water at half the rate of non-moulting ones. The threshold humidity for survival of these insects is within the range 52.5-62.5% R.H. The weight of mature animals does not vary at different humidities above the threshold. In general, the patterns of humidity requirements and regulation of water loss of G. colchici do not differ from those of other insects. There is no evidence that the dependence of these animals on temperatures in the 30-40C range for survival and reproduction is connected with more efficient control of water loss under these conditions.