Red Admiral overwintering 2017-2018

[Pete Eeles]

Brilliant work, Vince; I am in awe!

2 more 1st instar larvae found today, without any real effort!

Cheers,

- Pete

[Neil Hulme]

Hi Vince/all
I find this thread absolutely fascinating; the real-time monitoring of a species' behaviour, as it continues to undergo a fundamental change since the end of the last century. The Red Admiral is clearly determined to be a 'winner', and is a very welcome addition to the truly British fauna.
BWs, Neil

[David M]

Indeed. This would never have been commented upon even 20 years ago, much less 30 or 40.

Without doubt, the Red Admiral is the most active butterfly species in the UK from mid-November onwards, and given the lack of seriously cold weather we receive these days prior to Christmas, I would expect this pattern to continue.

[Pete Eeles]

Some photos from today It does make me wonder what the white spots that develop on a 1st instar larva represent, since there are no white markings on the 2nd instar larva (at least, initially).

1st instar larva pre-moult

2nd instar larva

Cheers,

- Pet

[Pete Eeles]

Some photos from today It does make me wonder what the white spots that develop on a 1st instar larva represent, since there are no white markings on the 2nd instar larva (at least, initially).

And so - that particular 1st instar larva has moulted into a 2nd instar larva that DOES have white markings on it (it is not the 2nd instar larva shown)! I'll upload a photo when I get a chance. It would seem that the variation in appearance of different larvae starts at a very young age!

Cheers,

- Pete

[Paul Harfield]

I visited my site at Southwick (Hampshire) on Sunday to see what was happening in the Red Admiral world. This site appears to be very similar to Vinces site at Crawley. A significant length of old brick wall which faces South/South East. Behind the wall there are mature trees providing shelter and roosting habitat. The site lies at the base of the Northern side of Portsdown Hill and is reliable for Red Admirals all year round.

This site at Southwick is very similar to Vinces site at Crawley

3 eggs on the same leaf showing slightly different colouration indicating they were probably laid at different times

Whilst I did not do a systematic egg count, I was able to locate x72 eggs with ease and I am sure there were many many more. I was also able to locate x1 1st instar larva and x10 2nd Instar larvae (2 of which I had marked previously). The 1st & 2nd instar are primarily found at the growing tip of the Nettle plant. As the 2nd instar larvae mature they will move to a side leaf and construct a typical leaf rolled downwards at the edges into a chamber. At least x3 larvae were found at this stage.

Typical location of 1st and young 2nd instar Red Admiral larvae at the growing tip

1st instar Red Admiral larva. The only one I managed to locate.

One of ten 2nd instar Red Admiral larvae found. This one having moved on from the growing tip to its new location

I spotted the first adult at about 11.35. This was a female which was observed laying more eggs from 11.45. I saw at least 2 different females laying eggs and a total of 5-6 adults altogether. By 12.35 the sky had started to cloud over and the temperature had dropped noticeably. I saw no more adult activity after 12.45.

Several adults were seen including these 2 females actively laying eggs

I will aim to visit this site at least every 2 weeks over the winter and report how things are progressing

[Vince Massimo]

Well done, Paul. That seems to be a much more sheltered site than mine in Crawley, with greater potential for winter sightings. I have never had two females egg laying at the same time, nor seen more than two flying together. I would be inclined to call your largest larva a 3rd instar.

Vince

[Pete Eeles]

Great observations, Paul; I need to find me a long south-facing sheltered wall

Cheers,

- Pete

[Pete Eeles]

Some photos from today It does make me wonder what the white spots that develop on a 1st instar larva represent, since there are no white markings on the 2nd instar larva (at least, initially).

And so - that particular 1st instar larva has moulted into a 2nd instar larva that DOES have white markings on it (it is not the 2nd instar larva shown)! I'll upload a photo when I get a chance. It would seem that the variation in appearance of different larvae starts at a very young age!

And here's the photo of the newly-moulted 2nd instar larva I promised. Not the best of photos, but I do like the fact that you see the 1st instar head capsule in all its glory!

Cheers,

- Pete

[Paul Harfield]

I would be inclined to call your largest larva a 3rd instar.

Vince

Thanks Vince. I have had another look at other images and I think you are right. This was in fact the largest larva I observed. Here is another view of the same larva removed from its larval tent.

[peterc]

I paid another visit to Knebworth Park today to find out how the Red Admiral eggs are faring. They might have all hatched by now and I found one empty egg case (which perhaps suggests hatching took place in the last day or two. Can anyone tell? See photo) although there were other leaves which had transparent 'bits' on them. I looked for RA larvae without success - probably tiny now and therefore difficult to find although there was some leaf damage.

I attach images of the habitat and the south=east facing nettle bed containing the eggs which were mostly found towards the path.

ATB

Peter

[peterc]

On a freezing, sunny morning at Knebworth Park the empty egg I found on 4 Dec is still intact. About 3 feet further back on the nettle patch were two plants with drooped leaves. Under one of them was a Red Admiral larva about 1 cm long (3rd instar?) and possibly another under a leaf on the left. Will the larva(e) withstand the cold?

ATB

Peter

[Vince Massimo]

Today I revisited the cemetery wall site in Crawley. Despite the air temperature being only 3C (and the base of the wall at 8C), I found two freshly hatched 1st instar Red Admiral larvae crawling about in the open. One was on a leaf next to a unhatched egg and the other was in the crown of the same plant looking for shelter.

Red Admiral 1st instar larva (A) and un-hatched egg - Crawley, Sussex 9-Dec-2017

Red Admiral 1st instar larva (B) - Crawley, Sussex 9-Dec-2017

One had definitely come from the group of eggs on the lower leaf of the plant (egg below centre), while the top egg hatched around a week ago.

Red Admiral eggs and larva - Crawley, Sussex 9-Dec-2017

Just to demonstrate how ridiculously small the leaf is, here it is 9 days ago, before the two eggs hatched, against a 5p piece.

12 Red Admiral eggs - Crawley, Sussex 30-Nov-2017

There were quite a few possible (1st instar) larval tents, but only one was investigated and it contained a late 1st instar.

Red Admiral 1st instar larva - Crawley, Sussex 9-Dec-2017

A fresh recount carried out over the course of two days resulted in a total of 276 eggs (down from 439). Some had clearly hatched, but others had gone without trace. I also saw a small parasitic wasp close to an egg.

Yesterday I checked the other site near the Football Stadium and confirmed six 4th instar larval tents. I was able to determine this by peeking down the hole in the end of the tent and so avoided any disturbance. Five of the tents were of conventional design (leaf folded upwards), but one was folded downwards.

Red Admiral larval tent (4th instar) - Crawley, Sussex 8-Dec-2017

Red Admiral larval tent (4th instar) - Crawley, Sussex 8-Dec-2017

In my garden I have a number of rescued larvae which came from the Stadium site, which are on potted nettle and un-netted. These are at 4th and 5th instar stages and came from eggs laid on 18th September.

......... I found one empty egg case (which perhaps suggests hatching took place in the last day or two. Can anyone tell? See photo)

Peter - It is difficult to determine how long ago an egg may have hatched, because the empty shell can survive intact for several weeks.

On a freezing, sunny morning at Knebworth Park the empty egg I found on 4 Dec is still intact. About 3 feet further back on the nettle patch were two plants with drooped leaves. Under one of them was a Red Admiral larva about 1 cm long (3rd instar?) and possibly another under a leaf on the left. Will the larva(e) withstand the cold?

They have a good chance of doing so if they are in a tightly constructed tent, but extreme cold can kill them as well as the host plant.

Vince

[bugboy]

A visit to Bookham turned up a single Red Admiral egg today. It is located in a glade where a couple of paths meet and is a spot where I have regularly seen freshly emerged early adults in previous years, too early and in too good condition to be migrants.

on the leaf pointing south-east.

The air temperature was hovering around 3 degrees so although it does look like a freshly laid egg, I would presume its age would be rather difficult to know.

A couple of context images with the eggs position arrowed

[Paul Harfield]

Saturday 16.12.2017 - Today I revisited my primary Red Admiral study site at Southwick in Hampshire, 3 weeks on from my last visit. The new Nettle growth here is still in pretty good condition after recent frosts with plenty of lush new growth. It was sunny up until about 1pm and although general air temperature was about 7 degrees it was pleasantly warm in front of the wall.

Still a few unhatched eggs as well as the remains of some hatched ones.

Still plenty of 1st instar Red Admiral larvae about

I was surprised not to see any adult Red Admirals, but early stages were simple enough to find once my eye was in. I counted 14 healthy looking unhatched eggs, significantly less than found previously. Most of these were in one small area very close to the base of the wall. Previously eggs were found well spread across the whole verge between the wall and the path which is a width of approximately 3 metres. I found perhaps 20 locations where there looked to be 1st/2nd instar larvae at the growing tip, but I only opened 2 of these as I was concerned about leaving the young larvae exposed when the temperature dropped. I was also able to locate 7 3rd instar (and a possibly a 4th instar) larvae one of which was found out in the open wandering across a leaf.

3rd instar Red Admiral larva as found out in the open

This was perhaps the largest larva seen. 3rd or possibly 4th instar.

I have tried to lay markers to enable tracking of specific larvae vist to visit but this is proving difficult. Some of my markers seem to have disappeared since my last visit so I have laid more. Unlike Vinces wall this one is not broken down in easy to recognise sections!

One of several larvae seen active within their shelters

Larval location marked with a stout twig pushed into the ground

[Jack Harrison]

This is excellent research and clearly shows that the conventional wisdom is wrong, namely that Red Admirals, if they do manage to hibernate, only do so as adults.

Jack

[peterc]

Vince, thanks for answering my queries on my last post.

Yesterday in Knebworth Park, no larvae were seen on the nettles where some of the tallest and more exposed plants are now dying probably because of the recent snow and cold weather. I did find two eggs but one of them on a dying leaf so perhaps not looking too good for this one

On the 14th, there was one nettle leaf folded up but I don't know if this is diagnostic for Red Admiral larvae or not. Alas I didn't find it yesterday.

ATB

Peter

[Vince Massimo]

On the 14th, there was one nettle leaf folded up but I don't know if this is diagnostic for Red Admiral larvae or not. Alas I didn't find it yesterday.

Hi Peter, the folded leaf looks good for a Red Admiral larval shelter, but it appears abandoned to me.

The recent mild spell of weather here in Crawley has led to some activity amongst the Red Admiral larvae that I am monitoring. Two of the larval tents in the garden show signs of recent feeding, while at the Football Stadium nettle bed I found a 4th instar larva out in the open as it prepared to build a new shelter.

Red Admiral larva (4th instar) - Crawley, Sussex 21-Dec-2017

The temperature was 12C with dark cloud and light wind.

Over at the cemetery wall site there are still over 100 unhatched eggs.

Vince

[Jack Harrison]

MALLOW. In Malta, and no doubt other places, Red Admirals seem to prefer mallow as the larval foodplant (I'm not sure nettle grows very well there in such a dry summer climate). I have artificially fed Red Admirals here on mallow. Now mallow surives winters quite well (as opposed to nettle which shrivels). It might be worth checking mallow leaves for larvae/eggs.

Jack

[David M]

This is a fascinating (and very probably, a recent phenomenon). 30+ years ago I'm sure Red Admirals weren't breeding like this in the late stages of autumn and early winter in the UK. However, given the evidence on display, it would seem that such behaviour is almost routine now.