Peacock caterpillars, Aglais io

After a cooler than normal April and May and a cloudy June I was worried by the low number of butterflies I had seen in the spring. I wondered if they would have an opportunity to breed and despite searching patches of nettles I hadn't noticed any nests of Small Tortoiseshell or Peacock butterflies. Normally, they are quite obvious.

Much to my relief on the 19th July I found some Peacock caterpillars on nettles in my meadow. It was just the one patch, rather than the normal two or three groups of caterpillars of both Peacocks and Small Tortoiseshells.

I kept an eye on them for a few days and by the 26th July they started to disperse a bit, so I collected two caterpillars to rear in a cage away from predators.

I was amazed by how active they were and how much they ate, requiring a new nettle stem each day.

By the 31st July one had formed into a chrysalis and the other was hanging from a silk pad it had spun on a leaf stem.

On 1st August I carefully carried the jar with nettle stem outside to photograph. I then put it back in its cage and when I looked ten minutes later its skin had split and it was starting for form a chrysalis. Yet again, I missed the actual moment when the skin split!

On the 13th August the first chrysalis emerged. It was the same story. Earlier in the day I had checked the chrysalis and when I checked ten minutes later there was a butterfly!!

Normally the chrysalis darkens a couple of days before the butterfly is due to emerge and the pattern of the underside of the wings can be seen. This give a pretty good indication of when the chrysalis will emerge. An hour-or-so before emergence the abdomen section of the chrysalis lengthens slightly and you can see the gaps between the segments pull away from the chrysalis as seen in the picture below.

The following day the second chrysalis emerged, again without me actually experiencing it! I am not complaining though, as I did witness this happening two years ago.