Strange dragonfly nymph behaviour

[Ukwildlifeo]

A few weeks back a hawker dragonfly nymph was caught and was placed in a tank to show the kids with about 8cm of pond water in. After seeing the group off I returned and too my horror it was belly up. So I quickly put it in a tray full of pond water and it recovered pretty quickly and stuck the end of it abdomen out of the water, blowing bubbles as it did (which I found in no way amusing ).

I put it in the photographic aquarium and, although it put its abdomen down when gently nudged it would soon raise it again and stick the tip out the water. It appeared to be not only breathing air, but dependent upon it. Has anyone else heard of/seen this behaviour? I thought they breatehd water until they left the water and 'held their breath' until the adult emerged?

Here's a a pic showing what I saw.

[King Edward]

Wheh they're preparing to emerge, I believe they transition to air breathing a few days or so beforehand and hence have to stay near the surface. I'm not sure how long this period lasts.

[RoyW]

Dragonfly will do this when oxygen levels in the water are low (as will damselflies), and in some cases will apparently even leave the water entirely if the air is suitably humid!