Soon after we built our garden pond (almost four years ago, and before we even moved in), we had our first Southern Hawker Dragonfly visiting. The Hawker family contain the largest of the dragonflies, including the spectacular Emperor. Southern Hawkers are big, bright and inquisitive – they will fly right up to you to have a good look at you through their multifaceted eyes – each eye has up to 28,000 lenses. This can be slightly unnerving! Every year we get females visiting to oviposit – lay eggs – around the pond. While other species will lay directly into the water the SH instead prefers to deposit her eggs in rotting logs. Although we do have a woodpile by the pond, all the SHs I’ve seen actually oviposit into nooks and crannies in the rocks we have lining the pond. You can see a female doing just that in one of the pictures below.
It seemed an odd thing to do because how are the newly hatched larvae going to get into the water? I actually rang the Dragonfly Society to ask them, and they told me that as water levels generally rise in the winter, the place where the eggs are laid should be underwater by the time the larvae hatch. That’s no good for our pond, though, because the water level never gets to the height of the rocks. That first winter I took the rocks on which I’d seen eggs being deposited, and placed them in the pond. No sign of SH nymphs in the years afterward though, although we’ve had lots of Red Damselfly, Broadbodied Chaser and Darter nymphs.
Until this week, when my daughter’s friend spotted this huge nymph. They are very distinctive in shape, so I realised immediately what it was. Normally our pond is a sanctuary of ‘observe and don’t touch’, but since this critter has been there for a couple of years at least and I’ve never seen it before, I couldn’t resist seizing the moment and scooping it out for a closer look. Remarkably, we then realised that it was just about to commence shedding its skin. Nymphs, or naiads as they are also know, regularly molt as they get too large for their skins. Just after molting they are pale, almost translucent, until their fresh skin hardens and darkens. Each stage of nymph development between molts is known as an instar, the final instar being the nymph’s last growth period before its final emergergence from its naiad form into a dragonfly.
Southern Hawkers spend around three years living underwater, although this depends on temperature and food supply. How I’ve missed this fella for the last couple of years is a mystery – they must prefer the depths to the shallows and rarely come to the surface. I certainly spend enough time pond-gazing! Our Broad Bodied Chaser nymphs were big, impressive critters – I was lucky enough to capture their emergence and metamorphosis last summer. Since then I’ve just seen a few little Common Darter nymphs. I wonder how many more SH naiads there might be lurking in the depths!
So here are some shots. I love the close-up of his jaws with the red-tipped mandibles. Nymphs have an impressive set of mouth armoury – their sharp, hook-like mandibles are attached to an extensible ‘mask’ which tucks everything away under the face but can shoot out at lightening speed to impale prey and bring it back to the mouth.