Collective States of the Nematode T. Aceti in Complex Geometries

We experimentally study the collective behavior of the nematode T. Aceti in complex geometries. Previous research has demonstrated that these nematodes can synchronize the oscillations of their bodies to produce collectively moving metachronal waves. In this collective state, they exert a strong pushing force at the front as well as create a fluid flow at the back with their tails. We leverage this pushing force to deform a flexible boundary between two fluids, where we discover several novel states. The most prominent one is of multiple protruding oscillating filaments, which have not been previously predicted in theory or simulations. We also study the collective motion of nematodes in oils, where we find that they can form propagating filaments that branch and connect, forming complex networks reminiscent of the ones formed by neurons.