Water requirements of relapsing fever tick larvae, Ornithodoros turicata (Acari: Argasidae), and the relative humidity of hatching eggs

Abstract

The argasid tick, Ornithodoros turicata (Dugès), thrives in stable, warm, dry microhabitats within the nests of their hosts. Exposure of eggs to relatively dry and humid conditions altered the water balance profile of resultant newly-hatched larvae. Tick larvae that developed at 75% RH contained less body water and absorbed water vapor from lower relative humidities than larvae that developed at 93% RH. No differences in net water loss rate and dehydration tolerance were noted between the two groups. For the first time, this suggests that the pump threshold, the lowest relative humidity required for activation of water vapor uptake, can be modified.