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Status and distribution
Aeshna grandis (Linnaeus) Brown hawker
Description Both sexes of this species are unmistakable in having a dark brown body with
wings suffused all over with an orange-brown tint. The sides of the thorax
possess two broad yellow bands. In males, there are a pair of large blue spots
on the dorsal surface of abdominal segment 2, a large blue mark laterally on
segment 3, and smaller blue marks along the sides of segments 4-8. There
are also tiny paired yellow markings dorsally on abdominal segments 2-8. The
eyes are brownish blue. In females, the blue spots on segment 2 are absent,
and the marks along the sides of the abdomen are yellow
Habitat A. grandis occurs on ponds, lakes, slow-moving rivers, canals and ditches. It is
one of the most frequently encountered large dragonflies in south-eastern and
midland counties of Britain, often visiting garden ponds and flying late into the
evening.
Breeding biology A. grandis is territorial and adult male densities rarely exceed 2 per 100 m of
water's edge. It is unusual also in defending territories away from water. After
a lengthy copulation, the female lays her eggs singly into the tissues of
emergent plants just below the water surface, or into floating aquatic
vegetation provided there is sufficient support for her not to become
completely immersed. Sometimes several females will settle on a small
floating log and oviposit close together into the wood, whilst at other times
they will show aggressive behaviour towards each other. The eggs pass the
winter in diapause. The larvae take from two to four years to complete
development, and live amongst submerged water plants. As with several other
weed-dwelling aeshnid species, such asil. cyanea and Anax imperator, a
proportion of first-year larvae are cryptically coloured, often with a banded
pattern. This may help reduce cannibalism and interspecific predation from
older larvae.
Flight periods A. grandis is on the wing from early July to early October. It occurs with the
many other species of dragonfly which breed in well-vegetated ponds and
waterways within its geographical range.
In Britain, A. grandis is widespread throughout the lowland areas of the southeast,
the midlands and as far north as Lancashire, Yorkshire, and the southern
fringe of Cumbria, with a few isolated records further north. There is a single
record from Scotland: from Colvend in Dumfries-shire in the mid-19th century.
A. grandis occurs in Wales along the arm of the Montgomery canal, and near
the border with Cheshire. It is absent from Devon and Cornwall. In Ireland, A.
grandis is probably more common in the central midlands and the south-east
than the records suggest — most of the fieldwork there having been done in the
early summer — but it does appear to be rare in some western districts,
notably western Co Cork and Co Kerry.
European and world On the continent A. grandis is found from France to eastern Siberia. It occurs at
distribution quite high latitudes in Scandinavia, but is absent from much of the
Mediterranean area.
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