To Swarm or Not to Swarm?

Science Signaling  03 Feb 2009:
Vol. 2, Issue 56, pp. ec37
DOI: 10.1126/scisignal.256ec37

In desert locusts, the radical transformation from a harmless “solitarious” form to the swarm-forming “gregarious” phase is one of the most extraordinary and iconic examples of density-dependent phenotypic plasticity in nature, as well as one of the most economically devastating. Now Anstey et al. (see the Perspective by Stevenson) reveal a neurochemical mechanism linking the changed behavior of individuals to profound changes in population structure, which, in this instance, lead to swarming and mass migration. The key to the phenotypic change is the ubiquitous neurotransmitter serotonin, which is synthesized in response to multiple sensory cues that gauge locust population density, switching locusts from mutual aversion to mutual attraction—the first and essential stage in establishing swarms.

M. L. Anstey, S. M. Rogers, S. R. Ott, M. Burrows, S. J. Simpson, Serotonin mediates behavioral gregarization underlying swarm formation in desert locusts. Science 323, 627–630 (2009). [Abstract] [Full Text]

P. A. Stevenson, The key to Pandora's box. Science 323, 594–595 (2009). [Summary] [Full Text]