The effect of prior exposure to predator cues on chemically-mediated defensive behavior and survival in the wolf spider Rabidosa rabida (Araneae: Lycosidae)

Abstract

Summary Adults of the wolf spider Pardosa milvina are intraguild predators of spiderlings of the larger co-occurring wolf spider Rabidosa rabida. We examined the effect of prior exposure to various Pardosa cues (visual, vibratory, and chemical) on predator-naive Rabidosa spiderling activity and survival. Each trial consisted of a pre-exposure movement test, 24-h exposure to one of five sensory treatments, a post-exposure movement test and finally a predation experiment with live Pardosa and associated chemical cues to assay the effectiveness of the spiderling’s response. The five 24-h sensory treatments were (N = 20/treatment): (1) Pardosa visual and vibratory cues, (2) Pardosa chemical cues only (silk and excreta), (3) visual, vibratory and chemical Pardosa cues, (4) chemical cues from a cricket (Acheta domesticus) and (5) no 24-h exposure to any Pardosa cues but chemical cues during the post-exposure movement test and during the predation experiment. In a sixth treatment we also measured spiderling movement and survival without any prior experience and no chemical cues from a predator. Rabidosa significantly reduced activity after 24-h exposure for all sensory treatments except the cricket and two no experience control groups. Treatments involving 24-h exposure to Pardosa chemical cues resulted in increased survival in the predation portion of the experiment relative to other sensory treatments. We conclude that (1) Rabidosa innately responds to Pardosa silk and excreta, (2) extended exposure to predator chemical cues enhances Rabidosa antipredator response and survival and (3) predator recognition is influenced more strongly by chemical rather than visual or vibratory predator cues.