Silk-mediated male courtship effort in the monandrous wolf spider Pardosa astrigera (Araneae: Lycosidae)

In nature, male wolf spiders may encounter silk of conspecific females, males, and/or both. It is generally accepted that males are able to discriminate maturity, sex, and mating status through silk-mediated chemical information of females. However, whether males can discriminate silk by chemical cues among virgin females of different post-maturation ages and between female silk with and without previously being occupied by other males remains largely unexplored. Given that female sexual receptivity increases in post-maturation, males are predicted to prefer old over young virgin females, and are able to discriminate silk of females which have and have not been previously being occupied by other males. In this study, we used the monandrous wolf spider, Pardosa astrigera, to test this prediction experimentally. When males were exposed to the silk of virgin females of different post-maturation ages (1-, 3-, and 6-day-old females), we found no significant differences in male courtship latency and courtship intensity to female silk across the different ages. However, males displayed significantly higher courtship intensity to the silk of females without being previously occupied by other males than to the silk of females with being previously occupied by other males. When males were directly exposed to virgin females, significantly higher courtship intensity was detected in males in response to 6-day-old females compared with 1-day-old ones. Thus, our results suggest that P. astrigera males can discriminate females using chemical cues from silk that has been previously occupied by other males and to older females with higher sexual receptivity, whereas they invest less to silk cues from virgin females regardless of their post-maturation ages.