A Black Caddis fly

We paid a short visit to Edinburgh this week and while we were there spotted this unusual black caddis on a bridge parapet at Stockbridge, over the Water of Leith. I think it is probably the longhorn caddis, Mystacides nigra.

It was smartly turned out in black livery (with just a hint of blue iridescence) and with eyes like garnets, but the most eyecatching features were those long white antennae - not just because of their size.....

.... but because of the way in which it waved them around, alternately waving each backwards then forwards.

Caddis flies, which belong to the insect order Trichoptera, are remarkable, both in the aquatic stage of their life cycle when most live inside tubes that they make from plant material or small stones, and when they are adults. You can see another example by clicking here and can read more about their biology here and here.

Newly-hatched caddis fly

I was sorting through some pondweed yesterday when I found this caddis larva. I don't know what the species is but I think it's one that lives between waterlogged dead leaves, rather than one that constructs a distinct tube to live in.

I could see that it was just about to hatch - you can see the well-formed wings in this picture.

A little later, when I looked again, the imago had hatched and climbed out on top of the waterweed. It's still drying its wings here and you can see the shed larval skin, down in the bottom right-hand corner of this photo. The caddis fly is still grooming one of its antennae.

Here's a the shed skin a little closer - I wish I'd been around to see the imago slide its long antennae out of their larval skin.

Still conducting pre-flight checks here.

One newly-minted caddis fly, ready to take to the skies.

If you've never seen it, it's well worth checking out this web site and this video, to see some amazing bejewelled caddis fly larvae.