Chalkhill Blue Pupae

[Dave Horsley]

I went looking for Chalkhill blue larvae yesterday - found some but also found some ants tending a small, brown, open case which just looked perfect for a larva to pupate in. There was a lot of ant activity. I don't think it was last year's case so do the ants build the cases to put the larva/pupa in? This seems a bit unlikely and requires some foresight. Does anyone out there know whether this might be a possibility?