In vitro studies on the environmental biology of Goniodes colchici (Denny) (Mallophaga: Isochnocera). 3. The effects of temperature and humidity on the uptake of water vapour.

Abstract

ABSTRACT Active uptake of water vapour, following previous desiccation, has been studied in the pheasant body louse, Goniodes colchici (Denny). Uptake is not continuous but occurs during limited periods of varying duration. Water vapour is taken up by adult lice at temperatures of 32–44 °C and at humidities of 60–100% R.H. The rate of uptake is not affected by temperature. The amount of uptake is not affected by humidity but is maximal at 36 ·8 °C. Water vapour is not taken up at humidities below 50 % R.H. At 55 % R.H. about half of the lice take up the normal amount, the rest none at all. Immature lice take up either much water vapour or none at all at temperatures of 32–44 °C; there is no temperature of maximal uptake. Lice are unable to take up water vapour during moulting and/or starvation. But within 48 h of moulting they are often able to take up enough to increase the body weight above its pre-moult level. It is concluded that in lice of this species the greater part of their water intake is by active uptake of water vapour. The conditions of temperature and humidity which these lice require for survival and reproduction can be understood on this basis.