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Nature
From Page B1
breed where they were bom. But some adults in northern populations forego breeding and instead migrate thousands of miles south to breed. And in some species, there are both migratory and non-migratory individuals.
The little that is known about dragonfly migrations is fascinating. Throughout much of North America, certain species undertake annual migrations north in the spring and south in the fall. The most obvious of these are the mass flights involving millions of individuals, but smaller groups are also observed. About 20 eastern species are known to migrate regularly and up to 50 species worldwide exhibit some sort of migrating behavior.
The migrations of the common green darner (Anax junuios) are best known. Each September, swarms of these dragonflies emerge as adults in northern breeding areas and migrate to Florida to breed. Their offspring are also migratory and fly back north in the spring. So they’re not like migratory birds that take round-trip flights from breeding to non-breeding areas. Migrating green darners take one-way trips only. One generation goes north and the next goes south, and each seems to know which way to go.
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