Researchers are studying the unique swimming techniques of a simply designed yet highly maneuverable jellyfish-like creature in order to inspire designs for underwater vehicles of the future.
Dubbed Nanomia bijuga, it’s a member of the siphonophores, a group of gelatinous planktonic creatures that are related to jellyfish, anemones and coral. Similar to coral, the two-inch Nanomia is colonial: It sports a gelatinous body that’s motored about by a nectosome made of genetically identical but separate components known as swimming bells (nectophores). Each of these act as mini turbo jets that shoot out streams of water, propelling the creature through the ocean.
Physonect siphonophores are colonial cnidarians that are pervasive predators in many neritic and oceanic ecosystems. Physonects employ multiple, clonal medusan individuals, termed nectophores, to propel an aggregate colony. Here we show that developmental differences between clonal nectophores of the physonect Nanomia bijuga produce a division of labour in thrust and torque production that controls direction and magnitude of whole-colony swimming. Although smaller and less powerful, the position of young nectophores near the apex of the nectosome allows them to dominate torque production for turning, whereas older, larger and more powerful individuals near the base of the nectosome contribute predominantly to forward thrust production. The patterns we describe offer insight into the biomechanical success of an ecologically important and widespread colonial animal group, but, more broadly, provide basic physical understanding of a natural solution to multi-engine organization that may contribute to the expanding field of underwater-distributed propulsion vehicle design.
SOURCES – Vice Motherboard, Youtube, Nature Communications