Migration
Unlike birds and butterflies, little is known about dragonfly migration, why they
migrate and where they are going. Like birds, dragonflies begin migrating south
from late summer to mid-fall. They seem to navigate south by using natural landscapes
such as mountains, seacoasts and large rivers. Large migrations have been observed
in the warmer climates, such as the Gulf of Mexico and other sub-tropic and tropic
climates.
In some species, migration is a regular part of the dragonfly's life cycle. One
example is the Common Green Darner, some populations of which show the same multi-generational
migration exhibited by butterflies. In general, adults fly north in the spring and
reproduce; the next generation flies back south and breeds there. Apparently some
of the gliders and possibly other species act in a similar fashion but little is
known about the workings of these migrations.
Other species such as the Rainpool Gliders (genus Pantala) continually wander over
great distances, often reproducing in temporary pools. Still others experience occasional
erratic eruptions and mass flights which may fall within the definition of "migration."
No one is certain was causes these events.
Dragonflies migrate as scattered individuals or in mass swarms. It is suspected
that meteorological conditions could possibly be one trigger, just as they effect
bird migration. Masses of migratory dragonflies have been frequently observed following
the passages of cold fronts. It has been noted that even in separate geographic
areas, separate swarms of dragonflies were observed after the same cold front.
Many theories exist without empirical evidence to back them up. To improve our understanding
of where, why and when dragonflies migrate, there have been a few projects that
have been established to gather information from around the country, encouraging
the hobbyist, backyard enthusiast and entomologist to record data on dragonfly movements,
weather conditions and flight directions during the migratory months. This data
when analyzed will give us a better understanding of these beautiful creatures that
share our world.
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