peacock hibernation

[Astonvilla]

It seems to me thatthe Peacock enters hibernation earlier than the other Vanessids, i.e., sometime in early August.
What is the experience of members? If you agree, why do you think this is so?

[Pete Eeles]

I'd have to agree. I'm still seeing Small Tortoiseshell (in the same genus, now ... Aglais!) regularly; most recently at Calstone Coombes in Wiltshire just yesterday. But I haven't seen a Peacock for weeks.

I have no idea why this might be and would also be interested in theories folk might have.

Cheers,

- Pete

[bugboy]

Hmmm, well I guess we can all agree that the adult overwinterers aim to get into hibernation mode asap to minimise predation before they can breed. Peacocks vanishing before Small Tortoiseshells may well be down to their respective summer breeding cycles, 2 broods for the Small Torts and 1 for the Peacock (I've never seen this written anywhere but I presume this is to avoid competition at the larval stage, same as what the 'Lysandra' blues do). This staggering of broods means that the Peacocks emerge earlier than the second brood Small Torts meaning they latter seem to hang around for longer... well it seems to make some sort of sense in my head anyway

[Pete Eeles]

Hmmm, well I guess we can all agree that the adult overwinterers aim to get into hibernation mode asap to minimise predation before they can breed. Peacocks vanishing before Small Tortoiseshells may well be down to their respective summer breeding cycles, 2 broods for the Small Torts and 1 for the Peacock (I've never seen this written anywhere but I presume this is to avoid competition at the larval stage, same as what the 'Lysandra' blues do). This staggering of broods means that the Peacocks emerge earlier than the second brood Small Torts meaning they latter seem to hang around for longer... well it seems to make some sort of sense in my head anyway

I'm not convinced that there's competition for resources at the larval stage in either case, to be honest I mean - Stinging Nettle is hardly in short supply (even the "right" nettle) and I'd suspect the same with Horseshoe Vetch (which is extensive on most chalk downland sites that are home to both coridon and bellargus).

But I would definitely agree that the number of broods is possibly a factor, and that getting into a torpid state ASAP might be linked to improved survival.

Cheers,

- Pete

[millerd]

I believe other single-brooded closely-related Nymphalids also go into hibernation early (Large Tortoiseshell, Camberwell Beauty?). It would appear to be the same strategy. From time to time Peacocks do produce a second brood, and adults are then in evidence right into September and October.

Dave

[bugboy]

I'm not convinced that there's competition for resources at the larval stage in either case, to be honest I mean - Stinging Nettle is hardly in short supply (even the "right" nettle) and I'd suspect the same with Horseshoe Vetch (which is extensive on most chalk downland sites that are home to both coridon and bellargus).

- Pete

I would presume that this staggered breeding cycle would have evolved long before humans cleared the vast tracks of wildwood that covered most of Europe when suitable patches of foodplants would be somewhat more hard to find than post civilisation. Thinking about it, it probably evolved as they speciated as a mechanism to prevent hybridastion as much as anything else...

Edit: we can also look at our other two adult hibernators as well, Brimstones (single Brooded) have normally all vanished by the end of August whereas Commas (double brooded) can still be seen into October.

[peterc]

I am baffled by this behaviour too - I understand that some Peacocks hibernate only one week after emerging. Could it be that they fatten up quickly then enter hibernation to 'save' themselves until the spring? Peacocks in some other parts of Europe are bivoltine or even trivoltine and even in this country in the far south very occasionally there is evidence of a second brood in September. If we see any adults in September obviously it doesn't necessarily mean they are second-generation individuals but if any of the immature stages (like larvae) are found then they would be. Perhaps this will be a more regular event in future due to climate-warming.

ATB

Peter

[Neil Freeman]

I must admit I thought that it was common knowledge that Peacocks usually disappear into hibernation fairly early, most are gone by early September although there is always the chance of seeing one on warm sunny days well after that.
The staggered brood theory falls down when you move further north in the UK where Small Tortoiseshells are often single brooded with timings more in line with the Peacocks.

Cheers,

Neil

[Mark Colvin]

It seems to me that the Peacock enters hibernation earlier than the other Vanessids, i.e., sometime in early August.
What is the experience of members? If you agree, why do you think this is so?

I personally experienced some fifteen individuals of A. urticae overwintering in an old converted tractor shed last year. They were surprisingly first seen to be entering hibernation on 31st July 2015. They stayed in this state for eight months and only occasionally showed signs of any movement. That said, whilst there are currently three residing in the tractor shed this year (first observed on 15th August), I saw two flying yesterday. I am sure there are a number of important biological and environmental factors which play there part in triggering the point at which adult insects determine diapause including date of emergence, daylight hours, food availability and the many factors and extremes of climate.

More at: http://www.markcolvin.blogspot.co.uk/20 ... eeper.html

Goods hunting.

Kind regards. Mark

[David M]

In my experience, there is usually an 'explosion' of Peacocks towards the end of July that lasts till around mid-August. After that, numbers diminish considerably but they do not completely disappear.

Additionally, Peacocks don't seem to wake up in spring quite as early as Tortoiseshells, Commas and Brimstones. I don't know why this is but there must be a reason, I suppose. If they used a different LHP to Tortoiseshells I could understand. Perhaps they wait a little longer for more nectar sources to flower, so as not to compete with the commoner Small Tortoiseshells in late February/early March when there is precious little available?

It may be noteworthy that whilst I've seen Tortoiseshells & Commas avidly nectaring on lesser celandines, I've never observed a Peacock on this species of flower. Perhaps they prefer to wait for the dandelions and tree blossom which comes a little later?

[Pete Eeles]

I've seen Peacock feeding on sallow flowers and also blackthorn flowers, which are both pretty early in the season.

Cheers,

- Pete

[Catteraxe]

A solitary Peacock seen today near Oxwich on the Gower. This one is clearly leaving hibernation to the last minute!

Kevin.

[bugboy]

For those who are following this thread who may have missed it in my PD a few days ago, some (probable) 2nd brood Peacock larvae found at Bookham Commons on 31st August in their penultimate instar. I wonder if there'll be enough warm weather left for them to fatten up (and enough flowers left blooming to feed on) .

[millerd]

I'd say they have a reasonable chance, Buggy. They could well be pupating before long and the forecast remains pretty good down here in the south, so they could be adults by the end of the month. Fingers crossed. I saw an adult Peacock today, the first round my way for several weeks. I assumed it had been disturbed from hibernation by a sudden day of hot sunshine after four days of cloud, but I suppose it could be newly hatched.

Dave