mixta (the Migrant Hawker) and Orthetrum cancellatum appear to be expanding in range
and abundance from strongholds in the south-east.
Dragonfly Behaviour
On emergence from the aquatic habitats in which they spend the early stages of their
life-histories, the adult dragonflies make a 'maiden' flight directly away from the
emergence site. Some subsequently return to the site of origin, but more commonly
there is a general dispersal of individuals. The aquatic habitats of dragonflies are in any
case often transitory because of natural ecological succession, or because of human
intervention. The ability to disperse, locate and colonise new breeding sites is therefore
essential to the long-term survival of most species.
After emergence some two to three weeks may be spent away from any suitable
breeding site. During this period some species, such as the large hawkers of genus
Aeshna may be seen hawking or basking in woodland rides or glades, well away from
water. The less powerful damselflies are generally to be found closer to their breeding
sites. When a suitable breeding site has been located many species show some territorial
activity. The males of several hawkers (such as Anax imperator, the Emperor Dragonfly),
darters (such as Sympetrum sanguineum, the Ruddy Darter), and damselflies (such as
Enallagma cyathigerum, the Common Blue Damselfly) may show quite aggressive
territoriality. Presumably such behaviour maximises mating opportunities for males
which successfully hold territories, and also secures 'choice', egg-laying sites for
females. Since it limits the number of breeding individuals in any one site, it
presumably also results in more effective dispersal of the population to other sites.
Only in Calopteryx species among the British dragonflies is there any elaborate
'courtship' activity, but all species share the distinctive 'wheel' mating posture (Fig. 2:3).
Fig 2.3 'Wheel' Mating Posture (in Enallagma cyathigerum)
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