Monday, 13 December 2010

Snow? What snow?

It always amazes me what can survive the sort of weather we've been having lately. Small birds suffer in harsh winters, and invertebrates are at risk of freezing solid. In Yorkshire we've had a good 8-10 inches of snow, temperatures down to -12C, and snow lying solidly for about two weeks. You've seen the pictures, so you know what it's been like. Now, I can quite happily understand how things survive underground, or in warm bits like decaying planty stuff, but you'd think that small creatures living exposed to the elements would have a hard time of it. A well-known method of killing insects for entomological research is to freeze them, after all.
   So, just as it was getting dark today, I went out into the garden to beat the Leylandii hedge with a box, to see what was lurking on it. The results from an truly minuscule amount of looking are as follows:

This one is a psyllid or jumping plant louse, Cacopsylla melanoneura (although there are several virtually identical species). It's very common everywhere, and lives mostly on hawthorn during the summer, migrating onto conifers when the leaves fall. For something 3 mm long, it's incredibly hardy.

For all you gardeners, here's an aphid. Not your typical greenfly, this is the Cypress Aphid, Cinara cupressae, which is a specialist that sucks the juice of Leyland Cypress. It was a concern for a while that this would decimate hedgerows across the country when it arrived in the UK, but that doesn't seem to be happening. Perhaps it doesn't like the climate...
For a bit more glamour, this was a beauty. Getting on for a centimetre long with that impressive ovipositor, it's some sort of ichneumonid wasp. I'm not going to even attempt to get further than that, as there are far too many species of wasps in Briatin, and most of them need to be dissected to tell them apart - or at least looked at by a specialist with a big microscope. You have to wonder what it's parasitising at this time of year, or whether it's just trying to survive the winter. A curiosity of this one is that the ovipositor appears to be hairy. That's just weird... how does it stick it into its victim?
One wasp is never enough, of course, so here's another. This is a little chalcid, barely 3 mm long, and like most chalcids, it's metallic. Not just metallic-looking, I hasten to add, but truly metallic - that cuticle is reinforced with zinc (or manganese, depending on the family). Stunning little creatures when you get the light right - I didn't, quite.
   Finally, how about this?
What on earth is a little squishy caterpillar doing out in this weather? It's presumably from some sort of small moth, but you'd think evolution would be kinder to it.

I'm not entirely sure how these creatures cope with the cold. Water of course freezes at 0C, but with all the various organic bits in, it will be a bit colder before critters like these go solid. I'm sure -12 would do it, though. There are various creatures, including fish, that have evolved anti-freeze in their tissues, and there's a bit of a summary here:

Nature never ceases to amaze me... and it's all to make sure we don't get bored in the winter. :)

1 comment:

  1. The caterpillar thing looks like a vine weevil grub to me. (Evil!! At least if you're a gardener.) They live on the roots of plants, and I think get through the winter that way - don't know what it would have been doing above ground though.