Searching for White Admiral larvae

[Pawpawsaurus]

Does anyone have any experience in searching for White Admiral larvae at this time of year?

Last summer I tried my hand at searching for eggs at a Hertfordshire hotspot, using as a guide the excellent Field Craft Lesson 1 document produced by Warwickshire Butterflies. Although I'd seen encouraging numbers of adults around I had no success in finding eggs, so I thought I'd try searching for spring larvae instead.

This afternoon I returned to the site and spent a couple of hours searching what I thought were suitable honeysuckle plants. No luck. Although I wanted to restrict myself to drapes hanging in partial shade, there was still relatively little foliage in the canopy and so most of the honeysuckle was in at least partial sun. It was therefore hard to know how shaded a given plant would be in July, when the females would be choosing the suitable ones. So I restricted myself to mainly south-facing honeysuckle, searching both for last year's still-attached dead leaves and for signs of leaf-nibbling (assuming that the larvae would be actively feeding by now). There seemed to be a scarcity of dead leaves in general, and the nibbled leaves which I did find proved fruitless.

Bearing in mind that even though my site is a hotspot, the Hertfordshire density of White Admirals is lower than that farther south, might I reasonably have been expected to find something in an hour or two?

I'd be grateful for hints from anyone who's had more success than me.

Paul

[Padfield]

I've had no success at all, mainly because I've looked for hibernacula in winter and had great difficulty identifying the honeysuckle! But maybe it will help to add a few pointers from Gabriel Hermann's bilingual book, Tagfalter suchen im Winter/Searching for Butterflies in Winter. He says that the banks of narrow, shady, woodland streams are best of all for the search and that preferred twigs jut out over the stream, where the humidity is permanently the highest. Other highly humid sites are also used, but humidity is an important factor. The lowest branches should be searched. Most hibernacula are on horizontal twigs 5cm - 20cm above the ground. What's true for the hibernacula is not necessarily true for the caterpillars but it might help direct the search at this time of year when they are just recently out of hibernation.

I'm going to keep a careful lookout for honeysuckle this year so I can identify the bushes next winter!

Guy

[Matsukaze]

If I remember rightly the German White Admirals tended to use a different species of honeysuckle (fly honeysuckle) which is not native to Britain and has a rather different growth habit to our species (being a shrub rather than a climber).

[Padfield]

You do remember rightly - he refers to fly honeysuckle throughout. I'm beginning to see why I've had no winter success finding the plants ...

But I presume the advice about humidity is valid regardless of the preferred foodplant.

Guy

[Pete Eeles]

Hi Paul,

I suspect that most larvae will have left their hibernacula by now - the few I'm rearing through all emerged a couple of weeks ago. Despite hours of looking, I've never found a hibernaculum in the wild, and have only ever found a fully-grown larva once, and never an earlier instar. Apparently, the first instar larvae are relatively-easy to find because of the distinctive feeding damage, but I've never found any. I've found ova - but only by watching an ovipositing female. And, as you say, the sites are always in full or partial shade and often quite shabby strands of honeysuckle.

To give you some clues, I've just taken a few photos of the newly-emerged-from-their-hibernacula larvae. Once you get your eye in they're not too difficult to spot, but are currently quite small (1cm long) and still brown, which matches a honeysuckle stem quite well. All larvae spend most of their time on the stems but occasionally venture onto a honeysuckle leaf to feed. I'd say your best bet is to look for larval feeding damage and I've tried to capture that in one of the shots below - hope they help!

Cheers,

- Pete

[Pawpawsaurus]

Guy: I have to admit that the passage you quoted confused me somewhat. Terms like 'twigs' and 'branches' didn't really seem in keeping with the honeysuckle I'm familiar with, but I didn't like to say so. As far as humidity is concerned, no streams flow through my wood although it does boast a fair few ponds. Maybe I should concentrate my efforts around those in future.

Pete: Thanks for the advice, and the photos. I wasn't sure when the larvae would normally be expected to resume feeding, but I guessed that there would be little point in them remaining dormant once fresh green leaves became available. The document I cited makes the searching process sound quite straightforward, which is why I was doubting my method. I did find occasional feeding damage but it didn't look recent and there was no sign of the culprit. I'l try again in a couple of weeks.

If I have any success, I'll report back.

Thanks, both.

Paul

[Pawpawsaurus]

I'l try again in a couple of weeks.

If I have any success, I'll report back.

Well I did try again, a couple of times, and my luck didn't improve. And now that Pete's captive larvae are pupating, I'm resigned to the fact that my searching time has run out.

This year I'll have to hope that I can find an egg-laying female whom I can follow while she goes about her business. I'd like at least to know whether the plants I've spent time searching are the kind of sites she chooses.

Paul