Of caterpillars and earwigs....

[Swirlything]

Hi! Been around the forum for a while, finally decided to sign up and post something. Well... 'bug' you lot with some questions, actually...*groan*

My garden (in South Wales) has a small patch of nettles etc. It's the only part of the garden to survive my father's garage-building and concreting-over spree many years ago; it's too small for anyone to bother doing anything with, so it's left wild, which is fine by me as I love the insects it attracts.
Anyway, this year as usual the nettles have been covered with various caterpillars. Most of these are small tortoiseshells- and also as usual they have been attacked by parasites. Hovever, I've noticed that this year there have been far more caterpillars dying from parasites (they are found dried up with several small yellow coccons next to them) and out of the twenty or so butterfly pupas that developed not one has produced anything but parasitic wasps. At least I think they're wasps....
In previous years I have seen far more caterpillars & pupas surviving to develop into butterflies.
So is it just me, or are there a lot more caterpillar parasites around this year? Perhaps this is because of the weather? *shrug*

Secondly, I've also seens a few Comma caterpillars this year, and a couple of months ago was lucky enough to watch an adult laying eggs among the nettles. This was a surprise, as I'd never seen one of these butterflies or its caterpillars before in my area. Are they normally found in South Wales and i've been unlucky not to see them, or are they increasing here?

And thirdly, are earwigs on the decrease? I used to see them everywhere as a child, but this year especially there seem to be hardly any around. It's a shame, they're fascinating little things!

[Paul mabbott]

Welcome swirl.
Difficult to say about the parasitoids: they tend to have wild population swings on a very local scale (e.g. in one nettle patch and not in another). As with most of these things, as the host population dies off the parasitoids have to do the same or migrate. Then the host population recovers and prospers for a few years before being found by the parasitoids &c &c!

Like you, I suspect that earwigs are on the decrease but difficult to prove this because, since they're such 'common' animals, nobody counts them or keeps records! I saw one in my garden yesterday which is the second one over nine years. I've seen few elsewhere whereas ten years ago I saw reasonable numbers (in the London area) but nothing like the numbers I used to see as a boy (don't ask how long ago that was!) in the Midlands. Is it a local thing or are they really declining?

Originally Posted by Swirlything

... this year as usual the nettles have been covered with various caterpillars. Most of these are small tortoiseshells- and also as usual they have been attacked by parasites. Hovever, I've noticed that this year there have been far more caterpillars dying from parasites (they are found dried up with several small yellow coccons next to them) and out of the twenty or so butterfly pupas that developed not one has produced anything but parasitic wasps. At least I think they're wasps....
In previous years I have seen far more caterpillars & pupas surviving to develop into butterflies. So is it just me, or are there a lot more caterpillar parasites around this year? Perhaps this is because of the weather? *shrug*

And thirdly, are earwigs on the decrease? I used to see them everywhere as a child, but this year especially there seem to be hardly any around. It's a shame, they're fascinating little things!

PS: seems a great use of a patch of 'waste' ground - not a waste at all ....

[Swirlything]

Originally Posted by Paul mabbott

PS: seems a great use of a patch of 'waste' ground - not a waste at all ....

Haha, yeah. I only hope the parents don't decide to get rid of it anytime soon (as they think it's an eyesore). Personally I think the concrete is even more of one...

Hm, I've noticed there's been a lot less variety in the invertebrates around here for the last few years.This year I've seen hardly any moths and they've all been the same few species, only one ground beetle (which was in the bathroom and had a good chew on my finger when I evicted him, bless) and just one two-spot ladybird. Yet when I was in Dorset last week there were wierd and wonderful creatures everywhere, including several hummingbird hawkmoths, dragonflies and lacewings. Shame I didn't have a camera.
Maybe it's a Welsh thing...

Oh, and does anyone know what's up with Tiger Moths? I haven't seen one in at least seven years!

Anyway, this seems like a really nice friendly forum, I'll probably be hanging round here a lot even if I do lurk more than I post

[aeshna5]

It's interesting about the parasitism of Small Tortoiseshell, because this used to be 1 of the commonest garden butterflies around London, yet in recent years has become quite scarce. I've had just 1 in my garden this year, though have seen a handful in local country park. I was sent a paper from the Hampshire branch of Butterfly Conservation which mentioned parasitoids suppressing Sm Tort populations.

[Paul mabbott]

Yes, but it's a bit cyclical. Anthony Allen wrote (about six-seven years ago) on the virtual absence of small torts in London and elsewhere. The next year was a boom one!
It is quite right to be concerned about these population depletions and very good that people have started to take notice of them .... however, before we start talking about population collapses, we need to have observations over ten (+) years ... in my opinion!

Originally Posted by aeshna5

It's interesting about the parasitism of Small Tortoiseshell, because this used to be 1 of the commonest garden butterflies around London, yet in recent years has become quite scarce. I've had just 1 in my garden this year, though have seen a handful in local country park. I was sent a paper from the Hampshire branch of Butterfly Conservation which mentioned parasitoids suppressing Sm Tort populations.