Effects of High Temperature in Rhodnius prolixus (Stål).

Abstract

Rhodnius fourth instar larvæ fail to moult at a temperature higher than 35° C; and at this temperature, or slightly lower, there is a disturbance in the hormone balance¹. This communication deals mainly with the results of exposing the different larval stages, directly after feeding, to 36.5° C for different periods, and then transferring them to 28° C, the optimum temperature. Such treatment results in delayed moulting in all the larval stages, and in a reduction in the numbers of sensory bristles and plaques which are differentiated and in their malformation. If the insects are kept at the high temperature before feeding, the same symptoms appear; there is also inhibition of the diuresis which normally takes place during the first 4 h after feeding², despite the apparently normal functioning of the Malpighian tubules.