Species of the Month: Southern Hawker Aeshna cyanea (July 2024)

This large and colourful hawker dragonfly is a recent colonist to SW Scotland. It is superficially similar to other hawker dragonflies, but can be readily distinguished with a good view. Males are brightly coloured, the black body contrasting with paired apple-green spots running down the abdomen which become pale blue towards the tip. The sides of the thorax are heavily marked with apple green. Females are brown with similar markings and less vibrant yellow-green colouration. The easiest identification feature is the bright and wide antehumeral stripes on the top of the thorax, just behind the head. In flight these are often described as looking like ‘headlights’.

Adults may hunt well away from water, for example on forest rides, and like other hawkers they fly for long periods without coming to rest. Thus, they can be difficult to see clearly and photograph. On the wing they are typically inquisitive and may approach closely to investigate anyone who strays within their territory. The species prefers less acidic conditions than the more widespread Common Hawker Aeshna juncea, but the two can sometimes be found in the same sites. Southern Hawkers are equally at home in garden ponds as well as larger ponds or lochs.

The species can also be identified with care by their exuvia (the cast larval skin when emerging from the water to become a winged adult). Searching for exuviae around pond margins is a good way of finding out which species are breeding at a site. This is particularly useful when weather conditions are not suitable for seeing adults on the wing (which does happen all too frequently in SW Scotland!).

Mark Pollitt

SWSEIC Manager