Of Caterpillars and Chrysalises

So far this year has been amazing for butterflies, but not only in their adult form. I also seem to have come across quite a few eggs, caterpillars and chrysalises.

It is always fun searching for Orange Tip eggs and caterpillars on Garlic Mustard and Cuckoo Flowers. This year they seemed to be on just about every flower spike I saw. This is a group of freshly laid eggs on a Cuckoo Flower.

In a couple of days they turn bright orange. I followed one egg with interest, which had been laid on a Garlic Mustard near the house. This was the caterpillar a couple of days after it had hatched.

The egg hatched on 11 May and I watched it develop until the 17 June when it formed a chrysalis. This is another caterpillar preparing to form a chrysalis.

And another one that unusually is about to form a chrysalis head down.

This is the chrysalis of the caterpillar I reared. It seems strange that it will remain in this state until April next year. 

On 13th May I saw a Green-veined White laying eggs on the leaves of a Garlic Mustard plant.

The eggs hatched on the 21st May and the caterpillars developed until the 30th June when they formed chrysalises.

On the 9th July both chrysalises emerged.

I have found three batches of well developed Peacock caterpillars amongst the nettles here. I haven’t noted the dates of any of these, as I didn’t know when the eggs were laid, or when the caterpillars formed chrysalises. However, on 3rd July I was demolishing an old shed and discovered a mature Peacock caterpillar on a piece of wood I had ripped off. Luckily it wasn’t injured, so I put it into a mesh cage, where it crawled to the roof and hung in a “J” shape.

Two days later it was still hanging there, but I noticed a 3pm it had moulted and formed a lovely green chrysalis.

This changed colour over the next few days and on 22nd July it emerged.

Sadly, it didn’t stick around for an open-wing photograph!

On the 5th July I was walking up our drive when I noticed a Red Admiral caterpillar crossing in front of me. Of course I collected it up and put it in a cage, where it immediately went to a Garlic Mustard plant and started stitching together the edges of a leaf to form a tent. The next day I noticed it had formed a chrysalis. I wasn’t very hopeful of a positive outcome, as I thought it unusual to find the caterpillar out in the open like that, as they usually hide away inside leaf tents. However, on the 22nd July it emerged, the same day as the Peacock. 

It was a lot more cooperative and allowed me to take some pictures of it before it flew off!

I have seen a lot of Red Admiral caterpillars and chrysalises in the nettles in our garden. There are a lot of adults flying around so hopefully they will soon be joined by more.

Orange Tip - Anthocharis cardamines

Following on from my posts about caterpillars that I had observed through to being butterflies last year, here is the story of some Orange Tips from this year.

Last July I was working on an old railway that is now a walkway and cycle path. I noticed a number of dried up Garlic Mustard seed heads along the edge of the path. I checked the seed heads and managed to spot two Orange Tip chrysalises.

The chrysalises are beautifully camouflaged and look just like a thorn, or part of the seed head.

I realised later that the plants along the edge of the path are cut back each year, so the next time I was there I found three chrysalises on the plants which would have been cut and took them away with me.

The seed heads with the chrysalises attached lived in my garage over the winter, next to the window. 

Every couple of weeks I would spray them with water to stop them drying out. I wasn't sure if this was necessary, but my reasoning was that if they were outside they would have been rained on, so I thought it was necessary.

Towards the end of April, I noticed that one of the chrysalises had started to change colour, showing the wing pattern of the butterfly. The other two chrysalises also changed shortly afterwards, revealing that they were all going to be boys!

On 29th April the first butterfly emerged, over nine months since I collected the chrysalis. The next butterfly emerged on 30th April and the third one emerged on 1st May. Although, yet again, I didn't see the butterflies emerge, two of them were waiting for me when I arrived home from work. The top of the container was left unzipped for them, but they appeared to be quite happy just sitting on the side of it.

It was good to know that I had helped three butterflies to survive, that would otherwise have been mashed up by a mower!

I planted a Garlic Mustard plant in a pot in the garden this year and I was delighted to see an egg on it on 19th May. I can't say when it was laid, but it was orange meaning that it was at least a day old.

On the 1st June I noticed a small caterpillar on the plant, which had probably hatched the previous day and today when I was searching for it, I noticed that there are two caterpillars on the plant, each on different flower stems.

And so the cycle continues!!

Red Admiral - Vanessa atalanta

2017 was generally not a  good year for butterflies here in South East Scotland, but strangely it was a very good year for Red Admirals, Vanessa atalanta.

In previous years the Red Admiral was considered to be a summer visitor to Scotland. They would arrive here from May to July from the continent and would lay eggs to produce the next generation, which it was thought either perished or returned south for the winter. However, over the last few years there have been a number of early sightings of Red Admirals here, suggesting that they are able to survive the milder winters we have had recently. Sadly, the long cold winter we have just had appears to have killed off all of the Red Admirals, but I notice that in southern England enthusiasts have found eggs and caterpillars throughout the winter.

The caterpillars nip the stems of nettles, causing the top to wilt over and then they create a little tent for themselves by stitching the edges of a leaf together.

Last year there were a lot of caterpillar tents seen and I decided to collect a couple to watch the caterpillars' development. I picked two nettles containing caterpillars on 22nd August and put them in a pot of water with other nettles for the caterpillars to feed on. It turned out the caterpillars were very close to forming into chrysalises.

Two days later, on 24th August, I noticed that one had formed a chrysalis on roof of the container. 

The other caterpillar had made its way to the top of the container and woven silk to form netting on the plastic window. The next day this caterpillar was hanging by its tail end from its silk pad.

The following day, the 26th August, the second caterpillar was still hanging by its tail end. I took the cage outside and within 30 minutes saw it was now forming a chrysalis.

It was a further 28 days before a butterfly emerged from the first chrysalis on 20th September. The second chrysalis also took 28 days to eclose, with the butterfly emerging two days later.

Unfortunately, they both emerged while I was at work, so I didn't see the adult butterflies. I was interested that they both chose to form their chrysalises on the roof of the cage. As far as I am aware they normally form the chrysalis within the tent they have made out of nettle leaves. Maybe the shelter of the cage made them feel secure.

The Peacock - Aglais io

The Peacock butterfly is reasonably common here in East Lothian. They over-winter as adult butterflies, seeking out dark places, such as old sheds and buildings, or deep in log piles in which to hibernate.

They are often the first butterfly of the year to be seen, appearing on a sunny day in February or March. The adults go on to breed and lay their eggs in large clusters on the underside of nettle leaves in May or June. Depending on the weather the eggs will go on to hatch about two weeks later. The caterpillars will take about four or five weeks before they pupate. They will remain as chrysalises for somewhere around two to four weeks, depending on the temperature.

So, there is one generation of this butterfly each year. The adult butterflies emerge here in August and their numbers peak around the middle of the month. They slowly reduce in numbers as they start to hibernate and by October we only see the odd sighting. However, after hibernation these same butterflies will be on the wing until June the following year. So, potentially, an adult can survive for up to ten months.

Last year I found an enormous group of caterpillars in a patch of nettles in a field where I walk our dog. I estimate that there must have been over 200 caterpillars there. I took this picture with my phone on 19th July, just as the weather took a turn for the worst.

The following day (the 20th) I collected three caterpillars and put them on some nettles I had picked, which I placed in a cage in the garage next to the window. They were at least out of the rain and protected from predators.

By the following evening, they were all hanging upside down from the nettles, looking as though they were about to pupate. They remained like that all day on Saturday 22nd, which was particularly wet and cold.

On Sunday morning, when I took a look, they had all turned into chrysalises.

During that period we had torrential rain for three days and when I took a look at the nettle patch I couldn't find any of the other caterpillars. I don't know if they had perished, or if they had also turned into chrysalises, which I couldn't find.

I had to wait for 24 days for my three chrysalises to emerge into butterflies on 15th August. I took the picture below before I went to work. You can see the pattern of the wing showing through the chrysalis.

And when I arrived home later that day, I was lucky enough to see the butterfly that had emerged.

The under-side of their wings is really well camouflaged among the dead nettle leaves, unlike the upper-side which is so beautiful.

Orange Tip - Anthocharis cardamines

My favourite butterfly is the Orange Tip, Anthocharis cardamines. When it first appears in April, I know that the butterfly season has started in East Lothian. Other butterflies appear around the same time of year, but they all produce a second generation later in the year. The Orange Tip only has one generation and in East Lothian they usually occur from mid April until the end of June. They are commonly found in the lush vegetation along the edge of water courses.

It is only the male that has the beautiful orange tips to its wings. The female lacks the orange and has slightly larger black tips to its wings. When they are freshly emerged they have a lovely checked edge to their wings and white antennae.

The underside of the wing is a marbled white and green and when they completely close up they are remarkably well camouflaged.

Around here the most common food plant for the caterpillars is Garlic Mustard, Alliaria petiolata. Cockooflower, Cardamine pratensis is also listed as a common food plant, but I have never found eggs or caterpillars on it. The adults feed on the flowers of both of these plants and you can see from the picture of Garlic Mustard below how the underside of the wing looks just like a flower head!

The spring and summer of 2012 was particularly rainy here and this appeared to have quite an impact on the butterflies trying to survive at the time. I didn't find one egg on any Garlic Mustard, but discovered that this year they had chosen a garden escape, Dames Violet, Hesperis matronalis to lay their eggs on.

The butterfly above is laying an egg and you can see the tiny white egg on the Dames Violet below.

Sadly the area where I do my butterfly transect is along-side the River Tyne and in July it flooded and all of the Dames Violet was submerged. After the waters subsided I didn't find any surviving eggs or caterpillars. Hopefully, there will be others on higher ground that have survived and they will colonise the river banks again next year.

The caterpillars are cannibalistic, and the female butterfly only lays one egg per flower head.

 Within a couple of days the egg turns orange ...

... and the caterpillar hatches sometime between one and two weeks later depending on the temperature.

The caterpillar lives its life feeding on the seed pods and by the fourth instar it has developed a white  shading to its upper side.

Up until this year I have never managed to find an Orange Tip chrysalis. The butterflies, eggs and caterpillars are relatively easy to spot, but the chrysalis is cunningly disguised as a thorn or bud. Last weekend I was at my father's house. He lives in a woodland and in a sunny spot I saw some dried Garlic Mustard seed heads. I spent some time searching them and the surrounding shrubs and I was delighted to find a chrysalis on a dried seed head of a Garlic Mustard plant growing in the wall of a derelict mill. I was thinking that if we have heavy snow this winter the Garlic Mustard plants would be flattened, but the plant with the chrysalis was beautifully sheltered under the branches of some elm trees. It is amazing that butterflies seem to consider these things when they lay their eggs!

I have been told that there are two colour forms of the chrysalis. Brown is more common than green. Now I know what I am looking for I will have a look for some more the next time I visit my dad. It is amazing to see the way the caterpillar has woven silk onto the stem of the plant to attach itself. It should remain there until next April, when hopefully it will emerge into a beautiful butterfly.