Of Caterpillars and Chrysalises Part 2

Continued from my previous post.

I can’t believe the number of eggs I have found this year of Large Whites, Small Whites and Green-veined Whites. There have been a lot of adults flying around and my Nasturtiums have been covered in eggs. 

The Large White lays its eggs in batches on the underside of the leaves.

The other two species lay their eggs individually anywhere on the plant. They have also been laying eggs on a Rocket plant growing in our patio and on Bittercress and Garlic Mustard.

I tried to photograph some Large White eggs and various stages of their development as caterpillars, but there were so many different batches of eggs I couldn’t keep track of which were which.

There were so many caterpillars that some of the Nasturtiums were completely stripped of leaves. I tried to pick leaves from other plants, but discovered that most of them had new batches of eggs on them. So, I resorted to buying bags of Curly Kale to try to keep the caterpillars alive! I have never seen so many caterpillars!

Once they were ready to form chrysalises they crawled up the wall of the house to find a sheltered spot.

Unfortunately, a few were parasitized by Braconid wasps. Presumably the adults had laid eggs inside the caterpillars at some point and the larvae burst out of the chrysalises to pupate.

And the Bluetits learned where to look for the caterpillars, flying up to the wall and picking off the chrysalises. Even the chrysalises that I had thought were safe were picked off by wasps, biting into the chrysalis and managing to prize them off the wall! I was feeling a bit despondent, seeing so many chrysalises perish after I had put the effort in to save the caterpillars. 

However, I needn't have worried. One day I noticed a Small White butterfly emerging from under the Alpine trough. I had a look underneath the trough and there were several more Small White chrysalises under there.

During the late summer/early autumn there have been loads of Large Whites, Small Whites and Green-veined Whites flying around.

On 12th July I noticed a hutchisonii form of Comma laying eggs on the nettles behind my garage. I wasn’t able to look for the eggs for fear of being stung, but on the 7th August, I was walking past the garage when I spied a little face peeking out from below a nettle leaf. It was a Comma caterpillar.

I watched it for a few days and on the 10th August it formed a chrysalis.

Unfortunately, it is now the end of September and nothing has emerged from the chrysalis, so I fear it may have failed.

I was down in my meadow one day in August, when I noticed a nettle bouncing around. I couldn't understand why it was moving like that on a still day. On closer inspection I noticed that the top leaves were stitched together and on top of the leaves was a parasitic Ichneumonid wasp.

I chased the wasp away and investigated further and found a Red Admiral chrysalis inside the nettle leaves. A little later when I walked back the nettle was bouncing around again and the wasp was back. So I decided to pick the nettle and put it in a mesh cage. I thought that in a few weeks I would either have a Red Admiral or a number of wasps! Luckily it was a Red Admiral that emerged from the chrysalis about three weeks later.

I don't think I have ever known such a good year for finding caterpillars and chrysalises!

Late Commas

Just to update my previous post. The Comma chrysalis that I found on the outside of my study window emerged on the 11th October. It had been lovely and sunny, but only 10 degrees Celsius and by the time it had fully unfurled its wings and dried out the sun was no longer shining on it. Eventually, it turned head down and settled down for the night roosting on its chrysalis.

That night the temperature dipped to 1 degree Celsius and we had our first frost of the year, but luckily it was sunny again the next day. The sun was low in the sky and it took until 10.30 before the sun reached the Comma. However, at 10.50 it had warmed up sufficiently to fly away. The temperature was 6.8 degrees in the shade.

On the 6th October I found a fully-grown Comma caterpillar on a nettle in the old hen run. This was exceptionally late in the season, as most of the books say that the chrysalises should all have emerged by the end of September.

I picked the nettle it was on and put it in a mesh cage I have under an overhang of the roof. Two days later it was handing from the nettle in a J-shape and on the 10th October it formed a chrysalis. I was intrigued to see if it would emerge a few weeks later if we had mild weather, or if it would survive as a chrysalis until the spring.

Unfortunately, yesterday morning I spotted that it had emerged, but hadn't managed to fully pump up its wings and had perished. It must have emerged on the 26th November, as I had checked that morning and it was still a chrysalis. Over the weekend the maximum temperature had been 6 degrees and it had gone down to -2 at night.

It was sad that it hadn't made it, but interesting nonetheless. As is so often the case, I am left asking many questions. Is it normal for Commas to continue laying eggs so late in the season? Possibly I have just never noticed them before. Or is this a sign of climate change impacting on their behaviour?

All of these pictures were taken with my phone as I was having camera problems at the time!

Comma, Polygonia c-album

The number of Commas I have seen here has been increasing year on year. This year I haven't seen quite as many as I did last year, but it seems there may be more to come!

On 21 July I was distracted again, when I was working in my study, by a Comma butterfly flitting about on the nettles outside my window. I realised it was laying eggs, so made a mental note of where I had seen it and at lunchtime I checked out a particular nettle stem. There I found an egg in the centre of the underside of a leaf.

I picked the stem and kept it in a jar of water next to my desk to watch it develop.

On the 28th July I noticed it had hatched and there was a little black caterpillar, about 2mm long.

The caterpillar tended to be quite inactive and remain on its leaf, only moving once the leaf had more or less been completely eaten. I was hoping to be able to determine which instar it was as it grew, but I became completely confused! So, below are some pictures as it developed. In this one it is two days old.

Here it is 12 days old.

And here it is at 20 days old. Every time I moved the nettle in order to photograph the caterpillar it would contort.

And here it is at 21 days old.

When it was 29 days old it spun a silk pad on a leaf stem and hung straight down from it. Of course it curled up as soon as I tried to take a picture! It remained like this for a day.

On the 21st August it formed a lovely chrysalis, mostly dark brown with two golden spots.

Two weeks later on 4th September I noticed that the segments on the abdomen area of the chrysalis had started to stretch apart, so I thought the butterfly  would soon emerge.

I didn't expect it to emerge so soon, though. Half an hour later when I looked, there was a butterfly hanging there!

I took the stick that it was now on outside into the sun. The butterfly remained on the stick for a couple of hours, then flew off onto a fence post, where it remained until about 4pm before it flew off.

On the 13th of September I noticed another Comma had formed a chrysalis on the outside of my study window. As I write this, on the 7th October, it is still there. Yesterday I found a Comma caterpillar on a nettle, close to where I found the egg in July. It looks as though it is fully grown and about to pupate, but it seems really late in the season. It will be interesting to see when these two emerge and if there will be any more Commas flying this year.

Double Brooders

Last year I tended to take a lot of pictures of butterflies on our land using my phone. I would always have my phone in my back pocket whenever I was working outside and it was easy to take a quick record shot, rather than running to the house to get my camera, only to discover that the butterfly had then flown away!

Imagine my horror earlier this year when I discovered that all my pictures had disappeared from my phone. Luckily Google Photos automatically backs up every picture I take and so I have spent many evenings sifting through them and downloading the better pictures onto my laptop.

Amongst the pictures I was keen to save were some of a hutchinsoni form of the Comma that I saw last August. This is a lighter form of the Comma, Polygonia c-album, which it is thought is a result of the caterpillar developing while the day length is increasing. i.e before mid-summers day.

This form goes on to breed again the same year. Normally, in Scotland, the Comma just has one brood a year. The double brood is more common in England. This is the first time I have seen this form of Comma, but apparently a few have been seen in southern Scotland in the last few years. Possibly another sign of the climate changing, or maybe just a result of the lovely weather we had last spring.

Here is the normal form of the Comma.

And in contrast here is an interesting dark Comma I saw a few weeks later. This gave the impression of being a purple butterfly when it was flying.

Also, in August I found a cluster of Small Tortoiseshell caterpillars.

Here the Small Tortoiseshell, Aglais urticae, is normally single brooded, but further south there are two generations a year. I have never found caterpillars that late in the year and this was definitely a second brood. Again, probably the result of the great spring. I reared one of the caterpillars, which emerged from its chrysalis on 11th September, very much later than the usual early July.

East Lothian Butterflies 2019 Part 1

There was a very clear correlation between the weather and number of butterflies seen in East Lothian in 2019. After a reasonably mild winter there was an unseasonably warm week at the end of February with temperatures reaching 16 degrees. Then it was cold again until the end of March. At the end of April we experienced an even warmer week with temperatures of 26 degrees. However, we still experienced a few hard frosts in May. The remainder of the year was quite reasonable, but it was interspersed with very heavy rain showers. The butterfly season ended abruptly at the end of October when the weather turned cool and wet.

Other than a couple of hardy Peacocks that appeared in January, the warm week in February brought out a flurry of species. We had seen seven species before the end of February, which must be a record for East Lothian. Things then went very quiet until the third week in March when the butterfly season truly started. Most species did very well in 2019, probably as a result of the very good weather in 2018 allowing the early stages of the butterflies to survive in good numbers. However, from July through to September there were occasional very heavy periods of rain which had a dramatic impact on butterfly numbers.

Despite having fewer people recording butterflies than the last few years we had a record 20,598 butterflies recorded in 2019 (16,875 in 2018). This was helped considerably by the enormous number of Painted Ladies that arrived on our shores in June and July, but even without them we had almost as many butterflies as in 2018.

Peacock, Aglais io

The first butterfly recorded in East Lothian in 2019 was a Peacock seen at Aberlady Local Nature Reserve on 11th January. A second Peacock was seen at Levenhall Links three days later. Peacocks have been recorded in increasingly high numbers over the last seven years, with 2019 being the best year yet. Numbers peaked in mid August, but then dropped very quickly again to single figures by the start of September.

Small Tortoiseshell, Aglais urticae

The Small Tortoiseshells waited until the warm week in February to show, with the first record being on the 17^th. They have been declining in numbers over the last few years. However, 2019 saw a bit of a revival in numbers when the new generation emerged towards the end of July. As usual, they quickly disappeared with many of them heading into hibernation surprisingly early in the season.

Comma, Polygonia c-album

The number of records of Commas has gradually been increasing since they were first recorded in East Lothian in 2001. However, they declined significantly 2016 presumably as a result of the lousy summer. Since then they have been picking up and in 2019 the recovery continued. The first Comma was seen on 25th February and, like the Small Tortoiseshell, their number peaked for a week at the end of August and then very quickly they disappeared. It will be interesting to see how many return next spring after their hibernation.

Painted Lady, Vanessa cardui

The big story of 2019 was the arrival on our shores of an enormous number of Painted Ladies. These came in two waves. The first at the beginning of June when we were amazed at the number of Painted Ladies being seen. But that was nothing compared with the number that arrived at the end of July when they were seen in their hundreds. Some of these would have been the young of the previous arrivals, but most of them were seen flying in from the sea. They were also noted flying in a very

definite westerly direction and records were received from all over Scotland including the Outer Hebrides.

I was interested to learn that Painted Ladies had done similarly well in the USA in 2019. So, on both sides of the Atlantic conditions must have been just right throughout the lives of four or five generations of butterflies.

I received records of 5395 Painted Ladies in 2019, a big difference from an average of about 80 over the last six years.

Speckled Wood, Pararge aegeria

The exceptionally mild week in February also brought about a remarkably early record for the Speckled Wood. In fact two were seen on February 26th basking in the sun on the coast at Prestonpans. There was another record on 22nd March. We normally wouldn't expect to see a Speckled Wood here until the middle of April, which is when we started to see them again in 2019. I can only imagine that the three early records were individuals that had benefited from the long summer of 2018 and had formed chrysalises late in the autumn.

The spring populations appeared in higher numbers than in previous years and I was expecting to see bumper numbers later in the summer. However, the heavy rains that we experienced appeared to knock Speckled Woods quite hard.

There were fewer Speckled Woods recorded in 2019 than in the previous year, but they are still doing well in East Lothian.

Small White, Pieris rapae

After such a great year for Small Whites in 2018 I was expecting to see great things in 2019. And it was a good year, but just not as good a year as last year! In 2018 we had records of almost 3500 Small Whites, but in 2019 we recorded 950. However, this is still good when compared with the average for the previous five years of about 360.

The first Small White seen in 2019 was on the 27th February. A good five or six weeks earlier than we would normally expect. The rest of the season was much as expected with a summer population about five times as great as the spring population.

Red Admiral, Vanessa atalanta

The first Red Admiral record of 2019 was on 27th February. This was most likely an individual that had survived the mild winter. There were a few more records in March and April, but it was the first week of June when they started to arrive on our coasts, about three days ahead of the first wave of Painted Ladies. There was another spike in numbers at the end of August, which could have been the next generation. Red Admirals continued to be seen in good numbers until the end of October.

Orange Tip, Anthocharis cardamines

Orange Tips did very well again in 2019. This was probably a result of the great year they had in 2018. They were fortunate that their flight period was before the heavy showers started, so the weather was kind to them.

The first Orange Tip of 2019 was seen on 31st March, about a week earlier than normal.

Green-veined White, Pieris napi

The first Green-veined White was also seen on 31st March. The spring population was a lot larger than average, with the summer generation just being a little more than normal.

Large White, Pieris brassicae

The Large White has never been as numerous as the Small White or Green-veined White. 2019 was a fairly average year for them, which is a little surprising considering how well they did in 2018. The first record was on 11th April and they were recorded through to the 28th September.

I'll continue with the rest of the butterflies seen in 2019 in my next post.