|Brachytron pratense (Muller, 1764),
the only species in the genus Brachytron which is a monophyletic genus
of European dragonfly of the family Aeshnidae containing the Hairy Dragonfly
(Brachytron pratense), also known as the Hairy Hawker.
Could potentially be confused with
other Hawker dragonflies, but its early flight season and relatively small
size are good clues to its identity. The Hairy Dragonfly is the first of
the large dragonflies to emerge each year.
|The Hairy Dragonfly is named for
its hairy thorax, distinguishing it from other hawkers. It has a long,
narrow pterostigma (the coloured, chitinous patch on the outer region of
each wing). The antehumeral stripes are usually thin and green. The Hairy
Dragonfly has coupled, oval-shaped spots on each abdominal segment and
a long, thin pterostigma. The male is dark in appearence and the spots
on the abdomen are blue. It has green ante-humeral stripes. The female
has yellow markings and much shorter ante-humeral stripes. Length around
55mm, It is smaller than other species in the genus Aeshna. It is the United
Kingdom's smallest hawker.
Like typical hawkers, the Hairy Dragonfly
preys in mid-air on flying insects. It then carries its food to a suitable
perch where it is able to eat and digest.
Mainly found near unpolluted, well-vegetated
water bodies. Preferred environment: mesotrophic to eutrophic pools and
small lakes and fens, also along slow flowing rivers, canals and disused
flooded gravel pits. Avoids oligotrophic and highly eutrophic sites. The
Hairy Dragonfly lives in ponds, lakes, fens, ditches, and canals rich in
vegetation. Some plants that grow there include the common club rush, common
reed, great fen sedge, and true bulrush. This dragonfly requires open and
sunny areas with dense vegetation for protection. Here they are able to
feed on flying insects, shelter, and grow sexually mature.
Although it is a common species,
it is susceptible to uncongenial ditch management and poor water conditions.
The is the reason the species disappeared for a few years, only to return
recently. More so then its other relatives, the Hairy Dragonfly will only
fly in sunshine and will hastily retreat if the sun happens to go in.
|The Hairy Dragonfly's flight period
is short and early, beginning in mid-May and ending in mid-July. Dead vegetation
and living stems growing in the water, close to the water's edge, provide
a home for the eggs. Two years later, larvae emerge by scaling plant stems
just above the surface of the water or possibly crawling inland for about
a meter where they have room to spread their wings.
Adults males are territorial and
patrol breeding sites low down amongst vegetation searching for females.
Females oviposit alone in dead or living plant material. Larvae hatch after
a few weeks. Live amongst plant debris. Larval development normally takes
2 years but can occur faster in warmer conditions. Larvae normally emerge
in early morning on plant stems usually close to ground.
Ovipositing in decomposing floating
rushes and sedges of canals, large ditches, dykes, and ponds where the
water is stagnant or has a feeble flow.