Influence of social interactions on the response to social cues in spiderlings.

Mutual attraction is one central mechanism involved in the maintenance of cohesion in group-living species and relies on a modulation of individual behaviours in response to the presence of conspecifics. Social markers left in the environment can play an additional role in the modulation of behaviours and can substantially impact the cohesion of social groups. In this study, our objective was to examine the interplay between the presence of social cues and the individual responsiveness to conspecifics in spiderlings. Spiders are relevant models to address this issue as juveniles lay silk draglines during their displacements and display a transient gregarious phase. We introduced single or pairs of spiderlings in an experimental arena covered with different amounts of silk. Our results indicated that the probability of moving increased with the presence and the quantity of silk in single individuals. In contrast, we did not find evidence for any influence of the quantity of silk on interacting spiderlings and we showed that social interactions inhibited the individual response to social markers. Overall, our study suggests that the influence of social interactions on the modulation of individual behaviours prevailed over the presence of social cues. We discussed our results in the framework of chemical communication to explain the interplay between social cues and social interactions on the modulation of individual behaviours.