Mate Attraction in a Burrowing Wolf-Spider (Araneae, Lycosidae) is not Olfactory Mediated

Spiders are mostly solitary living animals, and males actively search for females by using chemical cues. Compared with the overwhelming evidence demonstrating the role of spider contact sex-pheromones, support for the role of olfactory sex-pheromones in spider communication is scarce. In Lycosa tarantula (L., 1758), a Mediterranean burrowing wolf spider inhabiting dry and open habitats and dependent on chemical cues for mate searching, we investigated the role of olfactory sex-pheromones in mate attraction. We conducted both laboratory and field experiments, using multiple experimental approaches (two-choice olfactometer in the laboratory and pit-fall traps and two-choice open arenas in the field) and controlling for male sexual arousal. Our results support the hypothesis that mate attraction in this species is not olfactory-mediated. In the two-choice olfactometer, males did not orient preferentially to the side where the stimulus was concealed. Stimuli did not influence response latency or the relative time spent in the experimental side of the olfactometer. In the field, the effectiveness of experimental pit-fall traps baited with potential olfactory sex-pheromones did not differ from that of control traps. In the two-choice open arenas, males did not show any clear preference for the experimental half containing the potential olfactory sex-pheromone, nor did they show any sexual response. These results demonstrate that olfactory-mediated cues are not important during mate attraction in this species, and enforce the idea that habitat preferences and life style might explain the relative role of contact and olfactory-mediated chemical cues during spider mate searching.