Developmentally timed sensory integration enables efficient larval dispersal

Animals integrate internal and external sensory information to adjust movement gait 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 timeframe. Here we show that dispersal in Nematostella vectensis larvae is accomplished by a constant ciliary sensory-motor system that produces stimulus-induced movement. In contrast, neuro-muscular and sensory systems gradually increase in complexity during development, enabling movement-associated gait control through reafferent matching of external and internal 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 dispersal in a timely manner, appropriate to the physical challenges of its specific ecological niche.