Dragonflies

[watervole]

predatrix is visiting this weekend. I looked out of the kitchen window yesterday afternoon and said, "Look, there's an Emperor dragonfly over the pond."

She was duely impressed not only by my ability to spot the necessary details at that distance, but also by my obviously encyclopaedic knowledge of dragonflies.

Actually, it's pushover. There are loads of species of dragonfly in this country, but we've only had the pond since this spring and so every dragonfly is a novelty that quickly gets looked up in the book. We've had four different species so far this year, and they all have different habits and they tend to be at different times of year as well. At this time of year, any dragonfly over my pond is either a common darter or an emperor. If it's small and russet brown, then it's a male common darter. If it's small and a bit paler, then it's a female common darter. If it's big, it's an emperor.

So, look out, spot big dragonfly -"Hey, it's an emperor."

Some of them have rather interesting mating habits as well. I was watching a pair of common darters a couple of days ago. When the male and female get together, they join up in a hoop. The female is at the bottom with the tip of her tail just touching under the male's thorax and her head and legs holding onto his tail. He flies for both of them and they may rest among our raspberry bushes. (I believe this is when the sperm transfer takes place). They seem to spend several minutes like this, then, they change position and link up in tandem, the female's head joined to the male's tail. Now, they both fly. They go over the water together and the female repeatedly dips the tip of her tail in the water as she deposits her eggs.

I've watched other species egg-laying, and they all have different tricks. Some lay their eggs on the leaves of water plants, some do it in the mud at the side of the pond and some do it a short distance from the edge.

The larvae are fun too. I don't know which ones belong to which dragonflies (I don't have a decent book showing the larvae), but I know I've several different ones. They're ugly as sin and quite fast predators in the pond once they've grown a bit. They seem to range at present from a cm to 2cm in size. They look nothing at all like the dragonflies they will eventually become. All brown and ugly, one looks a bit like a moss-covered spider; another is almost translucent.

I'm really looking forward to seeing one emerge into a dragonfly, but I may have to wait until next spring for that.

Comments

[watervole.livejournal.com]

I use Dragonflies and Damselflies of Great Britain and Ireland by Steve Brooks.
It's got excllent diagrams and very informative text. It tells you a lot about their habits and lifestyles.

It's got a key for dragonfly larvae, but that requires catching one of them and stuffing them under a microscope to pick up the details. As there's only four possible parent species, I suspect I could probably do it faster from a photo in spite of so many of them being similar.
I'm mentally betting that most of the larvae we have are broad-bodied chasers, but I guess I'll have to resort to studying one against the key to be sure.