www.ukbutterflies.co.uk

I believe that some moths aestivate, but wonder if there are records of butterflies doing the same in hot dry periods. A Small Tort appeared in my outhouse a couple of days ago, and looks exactly like a hibernating insect. It is still there 72 hours later:
Tony M.

I had always presumed that a few first [summer] generation Tortoiseshells go straight into hibernation even as early as end of June. This is a strategy to ensure that at least some butterflies survive the following winter in the event that the normal late summer/autumn brood is something of a failure.

I have often had Torties enter the house in mid summer but have usually chased them out again. Last year, I caught one that came indoors, put in a box in a dark corner of the shed. I let it wake up naturally on the first warm sunny day of the spring. So far this year, none have come indoors but the box in the shed awaits them if they do; they will have some Orange Tip chrysalises in adjacent boxes for company. However (as I have said in another thread) the Orange Tips will be transferred to the fridge in early winter to prevent early emergence next spring.

Plastic boxes do not need any air holes - there's plenty of oxygen for these small creatures. But periodically, I do open briefly, especially in damp weather, to minimise the chances of desiccation.

Jack

I think Jack is right. Last year I received a record of a Small Tortoiseshell roosting in an old castle on 17th August and it appeared to remain there for the rest of the year. The summer last year was awful, but there were plenty of days that it could have been out and flying around through to October. We came to the same conclusion as Jack.