Social behaviour of spitting spiders (Araneae: Scytodidae) from Singapore

The social organization of Scytodes sp., a spitting spider from Singapore, was investigated in the field and in the laboratory. The characteristics considered were colony structure, maternal care, prey capture, prey sharing, adults provisioning with prey and how feeding regime influences the level of tolerance expressed by juveniles that were living together. The characteristics of this species were compared with those of other Scytodes species that have been studied previously. Based on our findings, we conclude that in this species, social organization is 'periodic-social', with extended maternal care, this being a type of 'subsociality'. The females of Scytodes sp. wrapped their eggs in a silk egg sac and used their chelicerae to hold the eggs until they hatched. Spiderlings tended to remain in their mother's web until the fourth instar (i.e. after the third moult) but they were also highly aggressive and cannibalistic towards conspecifics after the third instar. Females carried prey to their spiderlings and either fed alongside the brood or left them to feed alone. Spiderlings also captured large prey cooperatively by spitting onto, biting and feeding on it together. The occurrence of cannibalism among her juveniles did not appear to be influenced by whether the adult female was present or not, nor did it appear to be influenced by prey abundance.