Tuesday, 29 June 2010

Two of the groovier exuvia

There was a UK TV programme in the late '70s called 'Connections' where the presenter, James Burke, flitted randomly from one scientific item to another by means of the most off the wall and sometimes tenuous links.  I loved it, probably because it resembles what goes on in my own head.   For example, on a hot Tuesday last week, I watched the first big dragonfly I've seen this year speeding over an area of rough grassland at work. I always enjoy my annual re-aquaintance with these stunning insects.  It shot by fast and at a distance and the only identification I could manage was that it wasn't Cordulegaster boltonii (one of the few scientific names I seem to be able to remember for some reason), but this is....

Here are my 'Connections' that got me from the field to the photo:-
Dragonflies - helicopters - Noel Edmonds - crash - Hadrian's Wall - Sycamore Gap - my garden - my garage - Cordulegaster boltonii (because I suddenly remembered that I had a Golden-ringed dragonfly exuvia tucked away in a box in there somewhere from years ago.)

The exuviae of the dragonfly nymphs (ie the empty cases that they leave behind when the adults hatch out) have to be amongst the most mesmerising of natural objects you can find.  Perfectly detailed, yet perfectly empty.  All the fine features of the once living nymph are there to be explored. 
This photo shows the underside of the head and the large projectile jaw that fires out those crunching, jagged-edged weapons that make mincemeat of tadpoles.

I also found another one that I had forgotten about. This is the exuvia of a Southern Hawker Aeshna cyanea and whereas the golden-ringed has smallish eyes, this one's are immense and wrap over the whole head. It's worth a click to marvel at the detail. A hollow shell ready to walk off before your eyes.

Meanwhile, me and the family are busy watching the entire Life on Earth series right through again. In one episode, the Guv'nor shows a magnificent fossil of an early dragonfly* that had an astonishing wingspan of 75 cms (the largest insect ever known to have lived). Go on, measure it out on the table. It's immense. The most intriguing question for me however was not answered by the great man. What must it's nymph have been like?  The hawker nymph is fearsome enough at about 4.5 cm long but scaled up, the larva of Attenborough's fossilised monster would have been at least ten times the size - with jaws big enough to take the end off your finger.  'Ahw-sum' as my American niece would say.

(*footnote: there's a photo of a scale model here)


  1. Fascinating stuff. The exuviae are in such good condition and, I think, have a sculptural metalwork quality about them - good subjects for an artist to work from.

  2. Hi Rob. Yes I absolutely agree. Something fashioned out of burnished copper would look truly excellent. Know any sculpters?