The ontogeny of social behaviour among juvenile Caribbean spiny lobsters

Abstract

Ontogenetic changes in behaviour often reveal ecological forces that influence particular life-history stages. Postlarval ‘algal phase’ Caribbean spiny lobsters, Panulirus argus, live solitarily in vegetation, whereas older, ‘postalgal’ juveniles aggregate in crevice shelters. The shelter choice, activity patterns and social influence across the ontogenetic phases that span this period of habitat transition were experimentally examined in mesocosms. Algal juveniles (6–16 mm carapace length; CL) did not seek shelter with conspecifics or alter their activity pattern in their presence. However, postalgal juveniles (24–45 mm CL) both congregated in shelters and altered their activity pattern in the presence of conspecifics. The presence of same-sized conspecifics caused increased walking activity and decreased time spent in algal cover. These particular ontogenetic behavioural changes are concomitant with the habitat shift from vegetation (solitary) to crevice sheltering (aggregated). Social interactions, especially through the formation of groups, may influence the timing and character of the ontogenetic habitat shift in juvenile spiny lobsters.