Helmy N, Khalil G M, Hoogstraal H
J Parasitol. 1983 Feb;69(1):229-33.
Hyperparasitism is common in laboratory colonies of Egyptian Ornithodoros erraticus whether the ticks are on or off the rodent host. Sex, recent engorgement, and size appear to be major factors in this feeding relationship. Males, and nymphs that produced males (N-male), parasitized females and nymphs that produced females (N-female) more frequently than they parasitized males and N-male. Females and N-female seldom parasitized females and N-female and did not parasitize males or N-male. Engorging and recently engorged, large ticks attracted smaller unfed ones. No preferred attachment site was observed. Hyperparasitizing females and parasitized females weighed less, had a longer preoviposition period, and produced fewer eggs than normally feeding, unparasitized females. About 30% and 80% of the females parasitized by males and females, respectively, died within 3 mo; only 7% of unparasitized females died within the same period. The proximity of replete or engorging ticks may be sufficient stimulus for hyperparasitism. Additional factors may include production of an attracting kairomone by fed ticks or the absence under certain conditions of a deterrent to hyperparasitism normally produced by fed ticks. Borrelia crocidurae spirochetes are transmitted during hyperparasitism.
在埃及多变钝缘蜱的实验室种群中，无论蜱是否附着在啮齿动物宿主身上，重寄生现象都很常见。性别、近期饱血状态和大小似乎是这种取食关系中的主要因素。雄性蜱以及产生雄性后代的若蜱（N-雄性）寄生雌性蜱和产生雌性后代的若蜱（N-雌性）的频率高于寄生雄性蜱和N-雄性若蜱。雌性蜱和N-雌性若蜱很少寄生雌性蜱和N-雌性若蜱，且不寄生雄性蜱或N-雄性若蜱。正在饱血和刚饱血的大型蜱会吸引较小的未进食蜱。未观察到偏好的附着部位。重寄生的雌性蜱和被寄生的雌性蜱体重较轻，产卵前期较长，产卵数量少于正常取食、未被寄生的雌性蜱。分别被雄性和雌性寄生的雌性蜱中，约30%和80%在3个月内死亡；同期未被寄生的雌性蜱只有7%死亡。饱血或正在饱血的蜱的接近可能是重寄生的充分刺激因素。其他因素可能包括饱血蜱产生吸引异种信息素，或在某些条件下缺乏饱血蜱通常产生的对重寄生的抑制因素。在重寄生过程中会传播克氏疏螺旋体。
