Developmentally timed sensory integration enables efficient larval dispersal

Animals integrate internal and external sensory information to adjust movement according to the physical constraints imposed by body-environment interactions. Efficient locomotion is especially important in small organisms where the motile phase is ontogenetically restricted. Motile larvae of otherwise sessile cnidarians must disperse and identify a suitable habitat in a restricted time frame. Here we show that dispersal in Nematostella larvae is accomplished by a constant ciliary sensory-motor system that produces stimulus-induced movement. In contrast, neuromuscular and sensory systems gradually increase in complexity during development, enabling movement-associated gait control through matching reafferent (self-generated) and external sensory information. Together with ciliary propulsion, the developmentally timed appearance of sensory and neuronal structures endows the animal with the ability to integrate information to shape swimming behavior and achieve efficient dispersal in a timely manner, appropriate to the physical challenges of its specific ecological niche.