Sunday, 24 November 2013

A few more common dragonflies not yet on the blog - Trithemis

There are two (very common) and one less common, but certainly not uncommon, Trithemis species easily encountered in northern Vietnam. One is the very purple Trithemis aurora, a common, but excitingly beautiful dragonfly. There are after all many reddish, but few purple dragonflies about. The second is the dark blue (but with abdomen checkered with yellow) Trithemis festiva, a species occurring as far west as Turkey. And lastly, the somewhat different Trithemis pallidinervis, which sits with wings raised very much like the Idiataphe dragonflies of the New World. There is some difference in the way these different species from the same genus behave. T. aurora males sit often on exposed branches and twigs sticking out of, or overhanging the water. T. festiva likes to sit on rocks or concrete along or in streams and T. pallidinervis is a species not of streaming, but of standing water, and sits on emergents in heavily vegetated shallow waters. It is for instance common in Van Long, but I also saw it in Huu Lien recently. T. aurora females are easily found perched on the tips of branches, often quite high, from where they hunt, T. pallidinervis females can be found perched in the same way as males along lakes and pools, but females of T. festiva are rarely seen, at least by me. T. pallidinervis was introduced before, but for completeness sake, here an old specimen (in fact from Huu Lien)

As purple as it gets, Trithemis aurora, male

A different male

Trithemis aurora female, not a good photo, I know, just did not get round to taking proper pictures of it

Trithemis festiva, male, on a rocky surface

Trithemis pallidinervis, male, and a nice oldish one too

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