Nocturnal detachment of the tick Ixodes hexagonus from nocturnally active hosts

To determine whether the pattern of engorgement of Ixodes hexagonus Leach (Acarina: Ixodidae) in Central Europe may influence host specificity, the host relationships of the sub-adult stages of this tick were examined and the time of detachment compared with the activity patterns of various candidate vertebrate hosts. The main hosts for I. hexagonus appear to be hedgehog and fox. This tick species seems to be incapable of feeding on any rodent commonly encountered in the study region, or on reptiles or birds. Virtually all of these ticks detach during the scotophase, becoming replete mainly during the late evening and early morning hours, regardless of the kind of host or of the time of attachment. These nocturnally detaching ticks, paradoxically, focus their feeding on nocturnally active hedgehogs and foxes, in spite of the possibility that such behaviour might cause them to disperse from the nests of the host. Dispersion is prevented, however, by the tendency of these ticks to detach while their host naps. The tick-host association of I. hexagonus with hedgehogs may serve to perpetuate such zoonotic, Ixodes-borne infections as Lyme disease.     

Sperm precedence in the deer tick Ixodes dammini

ABSTRACT We determined whether female deer ticks Ixodes dammini Spielman, Clifford, Piesman & Corwin (Acari: Ixodidae) can be inseminated repeatedly and whether sperm from first or second matings take precedence in fertilizing eggs. Such information is essential to the design of attempts to reduce the fertility of these vectors of Lyme disease. Although spermatophores are present in about half of questing female ticks, they are present in virtually all those found on deer; the abundance of males on deer exceeds that of females and copulation is common. Females must be inseminated before commencing the rapid engorgement phase of feeding. Males need not be in attendance during feeding, provided that the female has been inseminated preprandially. Thus, preprandial insemination suffices to stimulate rapid engorgement, but less blood is taken than when the female is perprandially inseminated. Both types of insemination effectively fertilize eggs. Eggs from females sequentially inseminated by irradiated and non irradiated males, were fertilized mainly by sperm from the last male. Cobalt-irradiated males mate effectively and their sperm compete with those of non-irradiated males. Sperm from the second two sequential inseminations fertilize most of the eggs. By infesting deer with such irradiated male I.dammini , the abundance of these vector ticks may effectively be reduced.