Population regulation in ticks: the effect of delayed mating on fertility in Ixodes trianguliceps (Acarina: Ixodidae).

The paper describes an experimental investigation of the effects of delayed mating on both the time course of engorgement and the reproductive output by female Ixodes trianguliceps Birula. Males apparently do not mate with females off the host prior to the female's blood meal, and successful mating is less likely to occur within the first 3 to 4 days of the blood meal. If mating is delayed beyond day 7 of the blood meal, the rate of engorgement decreases sharply from day 7 or 8 onwards, until mating has occurred, after which engorgement is completed rapidly. Female ticks subject to delayed mating show a markedly reduced reproductive output, caused either by a complete failure to lay eggs or by a lower engorged weight and consequent lower egg production. The ecological significance of these observations is that they may reveal an example of inverse density dependent fertility, which, because of the destabilizing effect on the tick population, might be exploited in the control of ticks.