14 March 2010

South-western Billabongfly - Austroagrion cyane

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South-western Billabongfly - Austroagrion cyane

The genus Austroagrion has 4 species that are all found in WA, but Austroagrion cyane is the only one occurring in southern coastal districts. It belongs to the Coenagrionidae family, which has 13 genera and a total of 31 species. Although the South-western Billabongfly is the only local species from Austroagrion, there is a similar looking damselfly from a different genus called the Common Bluebell, Ischnura heterosticta, which in some regions co-exist, although I have not seen any around Esperance. They are easily separated by the markings behind the head; A. cyane has a blue dumbbell shape, whereas I. Heterosticta has only two blue unconnected spots. There are other differences, but they are less obvious or more variable.

Around Esperance, Austroagrion cyane is probably the most common damselfly and often there are several males together without any apparent aggression, unfortunately for them, females seem to be far less common. They prefer still or slow moving water and are probably attracted to the numerous ephemeral swamps in the region. Growing to around 2-3 cm (1’) in length, they can often be seen with others, including males of different species, waiting on aquatic vegetation for the arrival of females. Locally, they are permanent residents and during warmer months can be encountered in most suitable aquatic habitats.