Red Admiral, Vanessa atalanta

Last June on a lovely sunny day I noticed a Red Admiral, Vanessa atalanta, flying around our hen run, landing on some young nettles, Urtica dioica, that I had previously cut down. Once it had gone I had a look at one particular nettle plant that it had been showing a great interest in and found an egg. Thinking that it wouldn’t have a chance of survival I picked the nettle and put it in some water in the house.

The egg was laid on the 25^th June and four days later I noticed that it had hatched. The caterpillar was a clear green colour with a black head and it remained in the smallest leaves at the top of the nettle, where it weaved a small silk shelter.

On 1^st July I noticed that the caterpillar had changed into the second instar and was now dark with small spines. It was now about 4mm long.

After that it was very difficult to see the caterpillar as it made itself a beautiful tent by nibbling through the nettle stem causing the top to flop over. It then wove the serrated edges of a leaf together to create a little chamber to live inside. It clearly ventured out at night and ate other leaves and on occasion would build itself a new tent.

On 23^rd July I noticed that it had woven itself a little silk pad and had started to hang from it in a J-shape in preparation for forming a chrysalis.

On 25^th July it had shed its skin and was now a chrysalis.

It remained like that until I noticed the colour of its wings became apparent through the chrysalis. It remained like this for a couple of days and then, despite it being in my study on the 10^th August it emerged into a beautiful butterfly while I wasn’t looking!

It was fantastic watching it go through the whole process from egg to adult butterfly. It was particularly thrilling watching it fly off once its wings had fully expanded and dried out. There were a lot of Red Admirals on our Buddleias later in the year and it would be nice to think that they were descended from this particular butterfly.

Back in June on the same day that I saw the Red Admiral laying and egg I also spotted a Painted Lady laying an egg on some Woodland Groundsel , Senecio sylvaticus. It was similar to the Red Admiral egg, but had more ribs. Sadly we had really heavy rain the following day and the egg was washed away. It would have been great to have reared it alongside the Red Admiral.

Northern Brown Argus eggs

In a previous post I talked about my attempts to create a bank of Rockrose as an experiment to see if it is possible to replicate the area up the valley where Northern Brown Argus, Aricia artaxerxes, are found. The first batch of cuttings I took four years ago was a success and they are now doing well, so last year I decided to take some more cuttings so that I could expand the area.

In July I collected several shoots of Rockrose and made a tray of cuttings. Despite checking carefully when I was picking the shoots, once I got home I discovered that there were eggs on two of the shoots. One leaf had two eggs on the underside and another had one egg on its top surface.

So, I drilled a couple of holes in the lid of a jam jar and put the two shoots into water. Unfortunately, Rockrose doesn’t appear to like to grow like this and the leaves quickly dried up. I therefore had to replace the shoots every couple of days.

Six days later on the 25th July one of the eggs hatched and another hatched the following day.

They were incredibly small and remained on the top surface of the leaf, puncturing it and sucking out its contents, leaving small brown marks.

Most books say that the caterpillars feed on the underside of the leaves, but these two caterpillars spent as much time on top of the leaves as they did under them.

It was clear that putting sprigs of Rockrose into water wasn’t working well, so in August I found a small Rockrose plant that had been half dug up by rabbits. I put it in a pot and transferred the caterpillars onto it. This made them even more difficult to find as by this stage they were still less than 3mm long. 

I was hoping to note when they changed instars, but it was really difficult to spot the difference between each instar when they are so small. Also with them being so active, I was never sure which of the two caterpillars I was looking at!! I noticed on the 5th August that one of them was looking greener, so I presume it had shed it skin and was now second instar. On 18th August one of the second instar caterpillars shed it skin and the other did the same on the 28th August.

They continued to grow and I would spot them occasionally as they ventured from under the leaf they were feeding on. Then on 16th September I was unable to find them. I presume, and hope, that they went into hibernation. The pot was still in the house at this time, so it would have been day length that triggered this, rather than temperature.

Later that month I put the pot outside in a mesh cage. The Rockrose was rather depleted of leaves by this time, so I purchased some cultivated varieties of Rockrose and put these pots next to the wild Rockrose. My hope is that the caterpillars will reappear in the spring and transfer onto the new plant. I hope to report back later!