Repeated feeding of Amblyomma herbraeum (Acarina: Ixodidae) immatures on laboratory hosts. Host effects on tick yield, engorged weight and engorgement period.

Rabbits and sheep are unable to acquire a resistance to larvae and nymphs of Amblyomma hebraeum. After repeated infestation of hosts there is no progressive decline in either the tick yield or the engorged weight of fed ticks. Seasonal fluctuations in engorged weights do occur however, with the weight declining in early to midwinter and increasing in early to midsummer. Changes in hose physiology as a result of low temperature acclimatization appear to be responsible for the fluctuations. Tick yield is determined by the amount of grooming undertaken by hosts. The feedings periods of larvae and nymphs are dependent on the skin temperature of the host.