www.ukbutterflies.co.uk

I think this has to be a WLH caterpillar laid up for pupation. Can anyone confirm?





I'm rather hoping to find a pupa there if I check again in a couple of days...

Guy

It certainly is - and you can see the silk girdle around its body. Nice find!

Cheers,

- Pete

Great - thanks Pete. I didn't think it could be anything else, really.

Guy

In my experience it takes quite a few days before you see the pupa itself, possibly up to a week.

That long? Interesting. How long do they spend as a pupa, typically? Last year I saw my first adult at that site on 26th June, though it is an easy species to miss and doubtless was flying before that.

Guy

well... they fly here from start of July, maybe last week in June at a push... but you're obviously much further south... BC produced a booklet named " The White Letter Hairstreak Butterfly", by Martyn Davies, ISBN 0 9512452 7 9.... which states specifically 26-28 days pupation period in the UK.
They are the epitomy of my passion for butterflies, since they are around me locally, but ephemeral, and difficult to see or photograph.

Well, if it pupates today and spends, say, 26 days thinking, it should emerge pretty well exactly on the day I planned to take you to the woods for achine, Paul!

Guy

Despite gale-force winds and rain, he somehow managed to pupate before I paid a visit at 9.00pm this evening:





For the record, and again despite the wind, which was still blowing this evening, there were wood ants in the elm trees:



Thomas writes: "I know of no one who has found the chrysalis being attended by ants, but this is perhaps because among common British species, only wood ants Formica species climb trees, and few White-letter Hairstreak colonies occur where these abound". Well, they abound in my woods, so who knows?

Guy

I'm quite surprised at that comment about tree-climbing ants; I was watching some small black ants - Lasius sp? - making use of at least the lower 6' of a hybrid poplar just this week, although climbing to WLH pupa territory would have been much further.

Still yet to see any WLH larvae here though there are plenty of signs of WLH-style feeding damage on the leaves. Hopefully the butterflies will be out in the next couple of weeks.

I agree - black ants certainly climb the lower reaches of trees. They are all over the blackthorn where my brown hairstreak larvae are growing up, for example (though they'd be little protection against the main threat there - cows!). But I've never consciously noticed them up in the higher levels of elms or other mature trees. I shall keep my eyes open now.

Guy