Why little swimmers take turns

摘要

Gaspar Jekely and colleagues' paper on page 395 literally takes the eye. It provides a neat dissection of how the two eyespots in the larva of a marine worm (Platynereis dumerilii) perceive light, and then how the larva responds with differential beating of cilia and a directed, helical swimming action (6. Jekely et al. Nature 456,395-399; 2008). These stills come from a dynamic computer simulation, created from first principles, in the authors' Supplementary Information. They show the movement of six virtual larvae that are attracted to a shifting light source; the simulation is initiated in frames 1 and 2, and shows the larval reaction when the light source moves to three different positions (frames 3,4; then 5,6; and finally 7,8).