The site of active uptake of atmospheric water in larvae of Tenebrio molitor

Larvae starved and desiccated for 8 days will then take up water from 93% r.h., the gain ceasing by 7 days. The rate and amount of uptake were the same in those starved at 0% r.h. as in those starved at 53% r.h. Tying off the last abdominal segment prevents uptake while tying off the first abdominal segment allowed one-third as much gain as controls. This supports the theory that active uptake of atmospheric water is by way of the rectum and not the body cuticle. Because of the time taken to reach equilibrium, of the same uptake after exposure at 53% as after 0% r.h., and of a large overshoot in uptake, it is suggested that the phenomenon in this species is a by-product of drying the faeces and not a vital aspect of the physiology of water balance.