Red Admiral overwintering 2017-2018

[Vince Massimo]

The purpose of opening this topic is to provide a location to collate overwintering sightings of the immature stages of the Red Admiral.

Red Admiral eggs - Crawley, Sussex 1-Nov-2017

Red Admiral 3rd instar larva - Crawley, Sussex 17-Oct-2017

Red Admiral larval tent - Crawley, Sussex 1 Nov-2017

Red Admiral pupa - Crawley, Sussex 5-April-2017

Every winter for the past 4 years, a few reports have been received of the Red Admiral managing to overwinter through its immature stages (ovum/larva/pupa). It does this by slowing its development and progression through these stages so that an egg laid in October can produce an adult in late April the following year. A typical example (from 2015) shows how this takes place:

Egg laid 9-Oct-2015
Egg hatched on 6-Nov-2015 (after 28 days)
First instar for 12 days (moult on 18-Nov-2015)
Second instar for 29 days (moult on 18-Dec-2015)
Third instar for 24 days (moult on 11-Jan-2016)
Fourth instar for 57 days (moult on 8-Mar-2016)
Fifth instar for 28 days
Pupated on 5-April-2016
Emerged on 18-April-2016 (after 13 days)
Total of 164 days from egg hatch to adult

Nettle beds with fresh growth in sheltered, sunny locations are the best places to find eggs and the shelters of overwintering larvae. In past years, egg laying has been recorded in November and even as late as 2nd December, mainly at sites on or near the south coast, but so far this year (October and early November) this activity has now also been reported on inland sites in:-

Sussex: viewtopic.php?f=8&t=9571#p126074
Middlesex: viewtopic.php?f=29&t=6157&start=2040#p126205
Hampshire: report awaited (now received from Paul Harfield). See later post.
Hertfordshire: viewtopic.php?f=8&t=9571#p126133
Lincolnshire: viewtopic.php?f=8&t=9571#p126057

With so many sightings, this is a good opportunity to gather further data on this subject.

I will create further links to other significant reports as they are received or you can post your sightings directly here.

Vince

[David M]

Excellent source of information, as ever, Vince.

I shall be keeping my eyes open for nettle beds throughout the winter!

[Paul Harfield]

Great idea Vince . Please see my latest diary posting viewtopic.php?f=29&p=126273#p126273

[peterc]

Yes, great idea, Vince.

Yesterday, I checked on the nettle patch in Knebworth Park where I found an egg last Friday (3 Nov) and found two more on one leaf. Will keep an eye on this patch throughout the winter and let you know of any significant developments.

ATB

Peter

[Vince Massimo]

Thanks everybody. The important point is to monitor those egg laying sites to see how the larvae progress.
Paul - Sorry, I initially had you down as Wiltshire and awaiting data. Thanks for your latest post.
One other link to add from Bugboy who reported typical egg laying behaviour on the Sussex coast on 6th November.
viewtopic.php?f=29&t=8077&start=1480#p126224

Vince

[bugboy]

I also had some (probable) egg laying at Hadleigh Country Park in Essex on the 28th October. I wasn't able to check for eggs but the behaviour signified egg laying was occuring.
viewtopic.php?f=29&t=8077&start=1480

[Pete Eeles]

Vince kindly provided me with 4 eggs, 3 of which have hatched. I've attached a couple of photos that are both of a 1st instar larva. The change in appearance from newly-emerged to ready-to-moult is extraordinary, and something I've now observed in quite a few Nymphalidae (Glanville Fritillary had me very confused for quite some time!).

Newly-emerged 1st instar larva

1st instar larva, pre-moult

Cheers,

- Pete

[bugboy]

The change in appearance from newly-emerged to ready-to-moult is extraordinary...

- Pete

It certainly doesn't take them long to take on their trademark 'plump' look

[Vince Massimo]

Concentrations of Red Admiral eggs reported from Southwick (on 28th October) and Knowle, Hampshire on 11th November by Paul Harfield
viewtopic.php?t=6085&start=600#p126273
viewtopic.php?f=29&t=6085&start=600#p126423

10 Red Admiral eggs - Knowle, Hampshire 11-Nov-2017 (Paul Harfield)

Vince

[Vince Massimo]

Another large concentration of Red Admiral eggs found just over a mile from home. They were all on tiny plants growing tightly against the south-facing wall of a graveyard in Ifield, which is a neighborhood of Crawley. I counted over 100 eggs, with one diminutive sprig having 13 eggs on it. In the summer, this location was a hot-spot for Small Tortoiseshell and Peacock larvae and it looks like the nettle bed was strimmed about 8 weeks ago because the re-growth is still only very low.

Context of habitat of Red Admiral eggs - Crawley, Sussex 17-Nov-2017

4 Red Admiral eggs - Crawley, Sussex 17-Nov-2017

Also today, a butterfly at a known over-wintering site for adults, just around the corner from home.

Red Admiral - Crawley, Sussex 17-Nov-2017

Vince

[Vince Massimo]

A further visit to the cemetery wall nettle bed at Ifield, Crawley today found an egg-laying female (V1). She was observed to lay 3 eggs at around 12.30 and she stayed basking on the wall until 2.30.

Red Admiral (V1)(with eggs below) - Crawley, Sussex 19-Nov-2017

Red Admiral female (V1) - Crawley, Sussex 19-Nov-2017

A full count along the whole length of the wall produced 192 eggs, including one on a twig beneath a plant. On one tiny sprig were 7 eggs that could be hidden beneath a 2p piece.

7 Red Admiral eggs - Crawley, Sussex 19-Nov-2017

Red Admiral egg on twig - Crawley, Sussex 19-Nov-2017

Nearby were 3 further eggs, making a total of 195 for the day.

Vince

[Pete Eeles]

A full count along the whole length of the wall produced 192 eggs

Nice work sir

Cheers,

- Pete

[Vince Massimo]

Thanks Pete. I was there again today, just to remove some litter and put down some apples for the butterflies. The wall has a total length of around 58m which is split into 17 sections, which makes my surveying easier. Upon checking three plants that I had previously photographed on the 19th, I found additional eggs on them. On that date I counted 20 eggs in section 1 and today there were 36, so the total is now well over 200.

One section of cemetary wall

8+5 eggs on two plants - Crawley, Sussex 22-Nov-2017

I also disturbed a Red Admiral from the grass, but it was too windy and cloudy for any other activity.

Vince

[bugboy]

Fascinating thread. One would presume that the main cause of death (non human related) of these winter offspring would be vertebrate insectivore predation and weather related since any parasites/parasitoids would be hibernating. Or are some of them becoming more active in our milder winters

[Vince Massimo]

Fascinating thread. One would presume that the main cause of death (non human related) of these winter offspring would be vertebrate insectivore predation and weather related since any parasites/parasitoids would be hibernating. Or are some of them becoming more active in our milder winters

Hi Paul,
Apart from birds, I think preditors like slugs, snails, spiders and earwigs could still be active in the sheltered areas where these particular eggs are laid. In mild winters there would also be a problem with fungual infection. I believe that parasites and parsitoids should be less of an issue at this time of year, but have no data to back that up.

Vince

[Vince Massimo]

Another visit to the cemetery site in Crawley produced 2 female Red Admirals (V1) and (V2) and one of them (V2) was observed to lay at least one egg at around midday.

Cemetery wall - Ifield, Crawley, Sussex 23-Nov-2017

Female Red Admiral (V2) - Crawley, Sussex 23-Nov-2017

The egg total continues to increase, but a full count was not completed.
The temperature was approximately 12C, but with a brisk wind.

Vince

[peterc]

The eggs I found today in Knebworth Park where I discovered some earlier in the month are now turning yellow-green.

ATB

Peter

PS Vince, I am impressed with your count

[Pete Eeles]

I went out yesterday and, in the gales, found the constructions of 3 fully-grown first-instar larvae - two on the same plant (I prised the constructions apart to confirm ID).

There must be one heck of a lot of Red Admiral larvae about for me to be able to do that! Thanks, Vince, for the advice of looking wherever you've found Red Admiral larvae before!

Cheers,

- Pete

[Vince Massimo]

Well done Peter and Pete. Keep the observations coming .
I was back at the cemetery site in Crawley today. The sun was shining, but it was only reading 7C, so I was a bit surprised to see a female Red Admiral who appeared at 12.25. She basked for a few hours but did not lay any eggs. From her markings, I was able to confirm that she (V1) was also seen here on 19th and 23rd November.

Female Red Admiral (V1) - Crawley, Sussex 25-Nov-2017

I completed a revised egg count, which was done over the course of two days, and the total now stands at 439 eggs along the length of the wall. Only a few are newly laid since the last count, so the others must have been there all along. I found that the eggs are easier to see if they are viewed in shade. Sunshine tends to make them blend into the leaf. Some are darkening-up in preparation to hatch.

13 Red Admiral eggs - Crawley, Sussex 25-Nov-2017

Vince

[Vince Massimo]

Another visit to the cemetery wall site in Crawley today found an egg laying Red Admiral (V2). She was there between 12.00 and 12.30 and was seen to lay at least 15 eggs, including one on an already overloaded sprig.

Female Red Admiral (V2) - Crawley, Sussex 26-Nov-2017

14 Red Admiral eggs - Crawley, Sussex 26-Nov-2017

The air temperature was 8C, but at the base of the wall it was measured as 14.7C.

Vince