Wednesday, 1 August 2012

The Emperor Dragonfly Emergency

In late May large dragonfly larvae could be found all around the perimeter of the kitchen garden pond at regular intervals of about a foot. I knew next to nothing about these creatures other than they were ferocious predators with impressive spring loaded jaws and that the majority of their life was spent underwater.

Phil the gardener told me they were Emperor Dragonflies, which I believe are Britain's largest species. For the next couple of weeks I visited the pond regularly hoping to witness their emergence from the pond and into the air.

newly emerged adult Emperor Dragonfly

I imagined this would happen over a short time on a single day as with ants, but I was to learn (to my convenience) that the hatching season was spread over a few weeks and that individuals could emerge at any time of day. I also learnt how hazardous this transition could be for the dragonflies. A fair number failed to successfully emerge from their larval cases, getting stuck at various stages of the process.


The weather was often brutal, but just as many attempted to make it out on bad days as good, only for many to be blown back into the water they had just come from. The most tragic conclusions were where the wings failed to unfold and inflate properly - a perfect adult dragonfly with useless wings, so near yet so far...

empty larval cases

That said, I was amazed by how many dragonflies did emerge successfully from such a relatively small pond, well over a hundred in my estimation (from counting the empty larval cases). On the day I managed to film the entire transformation it took approximately 1 hour for the adult to emerge from the case, about 30 minutes for the wings to inflate and around another 30 minutes for everything to harden before being ready to fly.

wings drying after emergence

This was a warm breezy day, I guess that the time taken can vary depending both on the weather conditions and the individual (apparently bigger larvae seemed to get it done quicker). By next year I should have read my Dragonfly book and know more.

adult Emperor Dragonfly
Now the mature larvae have gone, a new generation of previously unseen small larvae are now prowling proudly in the pond. Now there is less chance of them being eaten, they'll be the pond's top predators until their own time comes to find their wings.

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