GUARDING AND SPERMATOPHORE DEPOSITION TN THE FREE-LIVING ERIOPHYID MITE VASATES ROBINIAE NALEPA

Sex dissociation means that males deposit spermatophores regardless of the presence of females, while females independently seek spermatophores and pick up a sperm. In this study I describe unique behaviour of insects and mites that practice sex dissociation guarding of pre-emergent females (so called quiescent female nymphs). In particular, behaviour which is exhibited by Vasates robiniae males. When competitors were absent in the vicinity of quicscent female nymphs, guarders deposited ca 0.8 spermatophores per hour and placed them around their mates in a manner in which two subsequent spermatophores were situated more frequently within a relatively long distance from each other rather than close to each other. Between the acts of depositions males alternately explored the closest surroundings of the nymphs, at the rate of ca 7.4 times per hour, and became motionless, mostly in bodily contact with the nymphs. Interestingly, while some males guarded until the quiescent female nymphs started moulting, others left their males at different times before moulting. Prior to departures, males markedly changed their behaviour, more frequently exploring and resting without bodily contact with the nymphs and tended to shorten the time of depositions as well. However, if males stayed with the mates until moulting, the forthcoming time of females emergence did not influence either spermatophore deposition, exploration or the motionless phase of guarding. During and after moulting, guarders also did not persuade or coerce females into picking up a sperm from their spermatophores.