Female ticks of Ornithodoros porcinus porcinus undergo a series of adult moults when fed on blood containing ecdysteroids. The supermoulted ticks are bigger, ingest larger blood meals and lay more eggs than normal females. However, their rate of conversion of blood into eggs and their oxygen uptake are reduced in comparison to normal ticks. Their ability to resorb the rehydrated salt crystals is impaired. They are unable to shed the cuticle of the Géne's organ area leaving the organ constantly protruding, thus making the ticks vulnerable to dehydration. These factors are probably responsible for the very high mortality and the failure of most of the ticks to moult at the third supermoulting cycle.
