I am lucky enough to have a large floor-to-ceiling window in my study, which overlooks a weedy area of our woodland. I am often distracted from my work by a butterfly fluttering past and on quite a few occasions I have seen butterflies laying eggs there.
On the 1st July I spied a Red Admiral flitting about from nettle to nettle. I made a mental note of one nettle where it had landed and sure enough, when I looked later there was an egg.
I picked the nettle and popped it in a jar of water. The hole in the lid was only just large enough for the stem to fit through, so that the caterpillar can't fall in! On the 9th July the egg hatched, producing a little black caterpillar. It hung around on the small leaf the egg was laid on for a few days, but the leaf started to dry up, so I cut the leaf and put it onto a fresh nettle.
The caterpillar immediately climbed onto the fresh leaf and tried to stitch the edges of the leaf together. This was rather ambitious for such a small caterpillar. As it grew bigger it did manage to stitch the edges of the leaf together to form a tent. The caterpillar would spend all day inside its tent, only coming out at night to eat or construct a new tent. It was rare to see the caterpillar in the daylight during this time.
By early August it had reached a good size and after a period of frenzied eating I noticed that the caterpillar was hanging upside down inside its tent. On the 7th August I saw that it had formed a chrysalis.
The chrysalises have amazing metallic green marks on them.
On 21st August, I noticed that the chrysalis had darkened slightly, and I thought that the butterfly would be emerging in a couple of days. However, about an hour later I looked round to see a butterfly hanging from the leaf!
It wasn't a particularly sunny day, but after a few hours the butterfly flew off to a nearby bush, to join the other Red Admirals feeding there.
So, this Red Admiral had been an egg for 9 days, a caterpillar for 29 days and a chrysalis for 14 days. I found another, much lighter, caterpillar in the nettles , which I put into a mesh cage on a nettle stem. A few days later it formed a chrysalis, but this one remained in that state for 21 days. It is interesting how much longer it took to emerge.
As I write this in the middle of September, there are still caterpillars and chrysalises on the nettles outside my window. The number of butterflies has dropped over recent weeks, but Red Admirals have been really abundant. Last week I counted 67 of them on my Buddleias and I noticed a few days ago they are also feeding on Yew berries.