Evidence of kin-specific communication in a temperate, subsocial spider Anelosimus studiosus (Araneae, Theridiidae)

Sociality in spiders is extremely rare but has evolved repeatedly and is found across multiple families, including Theridiidae. Potential benefits of sociality for spiders include the ability to capture larger prey, reduced predation on individuals, and reduced individual silk costs. However, there are also potential costs and risks, including reduced individual fecundity in larger colonies and inbreeding depression. In subsocial spider species, such as Anelosimus studiosus, females typically establish nests as solitary individuals and raise offspring without the aid of others. This experiment was designed to test for evidence of kin-specific communication between mother and offspring by inducing choice through a Y-branch experiment. Additionally, the mother's silk production was inhibited to determine if communication could occur through pheromones deposited with silk draglines. The results showed significant differences in the way spiderlings made choices after being exposed to silk draglines from their mother or from an unrelated mother (p=0.016). The spiderlings also chose differently when exposed to a mother leaving a silk dragline as opposed to following a mother incapable of producing silk (p=0.045). These results suggest a degree of kin-specific communication between mother and offspring and that the communication may be mediated through silk draglines. Such kin recognition could be important in understanding group cohesion and how kin selection might work to create social networks within typically asocial taxa such as spiders.