Collett, M., Despland, E., Simpson, S.J. & Krakauer,
D.C. 1998. Spatial scales of desert locust gregarization.
Proceedings of the National Academy of Sciences , 95: 13052-13055.
Central to swarm formation in migratory locusts is a crowding-induced
change from a "solitarious" to a "gregarious" phenotype. This change can
occur within the lifetime of a single locust and accrues across
generations. It represents an extreme example of phenotypic plasticity. We
present computer simulations and a laboratory experiment that show how
differences in resource distributions, conspicuous only at small spatial
scales, can have significant effects on phase change at the population
level; local spatial concentration of resource induces gregarization.
Simulations also show that populations inhabiting a locally concentrated
resource tend to change phase rapidly and synchronously in response to
altered population densities. Our results show why information about the
structure of resource at small spatial scales should become key components
in monitoring and control strategies.
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