The effect of isolation from conspecifics on spermatophore output of two species of eriophyoid mites.

摘要

Eriophyoids are group-living, phytophagous mites whose males place spermatophores on a substrate, while females seek them out and perform self-insemination. Various factors, for example, rainfall, extreme temperatures and predatory mites, can considerably reduce the population size of eriophyoids which, simultaneously, may influence their reproductive strategies and output. In this study, the effect of a relatively short, 2-day absence of conspecifics on the spermatophore production of Aculus fockeui (Nalepa & Trouessart) and Aculops allotrichus (Nalepa) was examined. These species differ in male reproductive strategies. Both A. allotrichus and A. fockeui males can deposit spermatophores in the absence of quiescent female nymphs (QFNs). However, when QFNs are present, A. allotrichus males guard the nymphs from other males and deposit spermatophores beside them. In contrast, male A. fockeui rarely deposit spermatophores beside QFNs and do not interact with competitors. Previous tests have revealed that spermatophore output of eriophyoid males kept in isolation can differ significantly from output in the presence of conspecifics. In this study, on the second day of isolation, males of A. allotrichus significantly increased their rate of spermatophore deposition, whereas the coefficient of variation (CV) for spermatophore output considerably decreased. In A. fockeui, in contrast, both parameters were similar on both days. Moreover, no matter how many spermatophores the males of A. fockeui deposited on the first day, they produced a similarly high or low number on the second day (positive correlation between the two days). However, if on the first day male A. allotrichus deposited a relatively high number of spermatophores, on the second day they produced a relatively low number, or vice versa (negative correlation). All inter-specific discrepancies in spermatophore deposition during the absence of conspecifics are discussed in the context of differences in male reproductive strategies, as well as possible differences in male energy budgets and rhythms of spermatophore deposition between species.Digital Object Identifier http://dx.doi.org/10.1080/01647954.2012.657679