The effects of pedipalp loss on the courtship and mating behavior of Pardosa milvina (Araneae: Lycosidae).
Male wolf spiders use the first pair of appendages, pedipalps, for copulation. Males of the wolf spider, Pardosa milvina, actively wave their pedipalps during courtship of females. Pedipalp loss is more common among adult males than females. Field surveys indicate that 3% of all adult male P. milvina wolf spiders have missing pedipalps (N = 228). We investigated the effect of pedipalp loss on courtship and mating behavior in P. milvina. Virgin males were randomly divided into four treatments: left pedipalp removed (N=36), right pedipalp removed (N=34), both pedipalp's removed (N=33), or intact males (N=36). We then paired each male with a randomly selected virgin female. We recorded time to initiate courtship, courtship duration, time spent mounted on the female, mounting success, and courtship intensity as measured by leg waves/min or body shakes/min. There was no significant difference in mounting success of males among treatments. However, pedipalp loss reduced courtship intensity which is significantly associated with mating success. Intact males suffered fewer predatory attacks by females than palpectomized males. Loss of the left pedipalp resulted in significantly less intense courtship, higher female aggression levels, and delayed onset of courtship compared to males missing the right pedipalp. We conclude that P. milvina exhibits biased pedipalp use during courtship and that pedipalp waving may function in reducing female aggression.