Appearance''A. isoceles'' is one of only two brown hawkers found in Europe, the other is ''A. grandis''. Both have a brown thorax and abdomen but ''A. isoceles'' has green eyes and clear wings and a diagnostic yellow triangular mark on the second abdominal segment. The hindwings have an amber patch at their base. In contrast ''A. grandis'' has yellowish wings and blueish eyes. The green eye of ''A. isoceles'' stand out even in flight and in practice it is not difficult to tell these two dragonflies apart. In addition to the morphological differences ''A. isoceles'' is on the wing much earlier in the year than ''A. grandis''.
Distribution''A. isoceles'' is found in central Europe and around the Mediterranean and, the lowlands of North Africa. It is more common in eastern Europe than the south western Europe; it occurs in Spain and Portugal but is local.
It is found wet areas, ponds, ditches and marshes, with dense vegetation and, in studies carried out in England, was found to be associated with Water-soldier .
StatusThe Norfolk hawker has always been a scarce and local insect in Britain. It used to be found in the Cambridgeshire fens but by the early 1980s the populations had greatly declined. It is now confined to relatively unpolluted fens and grazing marshes in the Broadlands of Norfolk and north-east Suffolk. It can be found in Hickling Broad and two national nature reserves: Mid-Yare NNR and Ludham - Potter Heigham NNR and at Castle Marshes in the Barnby Broad and Marshes SSSI. It is protected under Schedule 5 of the Wildlife and Countryside Act 1981 and listed in Category 1 in the British Red Data Books on Insects.
BehaviorIt is one of the earliest ''Aeshna'' dragonflies to be on the wing with a flight period from May to August. Adults do not spend as much time on the wing as other ''Aeshnas''. Males will fly around over a stretch of water defending a territory and if the pond is small the male will hover over the centre of the pond. Unlike other aeshnas, where the adults seem to be continuously on the wing beating up and down their territory, male ''A. isoceles'' come to rest on vegetation from time to time. Females oviposit onto plants and the eggs hatch in about 2 weeks. Larval development takes 2 years.
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