COURTSHIP AND THE ASSESSMENT OF VIRGINITY BY MALE BOWL AND DOILY SPIDERS

Early in cohabitations of pairs of bowl and doily spiders, Frontinella pyramitela (Linyphiidae), males and females court and pseudocopulate with no transfer of sperm, then may proceed to true copulations during which sperm are transferred. A male assesses female virginity during courtship and pseudocopulation. Only if the female is a virgin will he build a sperm web, charge his pedipalps with sperm, and then begin insemination. The data also indicate that (1) the male's assessment of the female's virginity depends on a signal (in contrast to a structural change) given by the female, and (2) the female can signal 'virgin' but not 'non-virgin'. Males that do not assess the females as virgin continue with pseudocopulations for highly variable periods of time (up to 4·5 h) and the decision to cease is apparently governed by a stochastic process, analogous to a random number generator, in the male. In constrast, the timings of other events (e.g. the virginity signal and the end of true copulation) during these reproductive behaviours are governed by quite different processes: the data are consistent with a model involving the steady accumulation or dissipation of some substance or drive. © 1990.