Early Season?

Folks. Wild Purple Emperor larvae are unusually well advanced, with early- to mid-final instar larvae present in West Sussex, West Berks and S Glos. White Admiral and White-letter Hairstreak larvae are similarly advanced (I haven't got a reading for Silver-washed Fritillary). 

This means that, as things stand, the Purple Emperor is likely to be on the wing in early June, possibly earlier. 

However, we've been here before, notably in 2011 when there was a fine early spring. That was followed by a cool May, which slowed things down, and then a wet June. The first Purple Emperor was seen that year on June 13th.  

Long range weather forecasting is extremely hard in the UK, but the indications are for a drier than average May, with a warm ending. The middle third of the month, though, is likely to be cool (but dry), which could slow larval development right down.  [Info from The Weather Outlook which I find fairly reliable].

Watch this space, but my original prediction for the first Purple Emperor of 2020 was June 11th - but I may well need to bring that forward.  

Regarding numbers: much depends on May and June weather, especially the weather when larvae are pupating, and during the pupal period, and of course flight season weather. Winter predation was 'Moderate', as measured. At this range, numbers could well be 
quite good or even good. 

Finally, I am delighted to announce the discovery of Apatura iris in the Cirencester area, probably as a recent colonist. There is a fair chance of the odd aggressive male beating the living daylights out of the Large Blues on Daneway Banks...  

His Imperial Majesty

My book, His Imperial Majesty, a natural history of the Purple Emperor will be published by Bloomsbury on June 11th. It aims to encourage and enable the proper study and appreciation of this wondrous butterfly, and to give it the future it deserves.

There are pre-publication offers with Amazon (£14.95) and Bloomsbury (£15.29, ebook £14.26). 

Here's the cover - 

More details are on my website, including the contents page: http://www.matthew-oates.co.uk/his-imperial-majesty-a-natural-history-of-the-purple-emperor/

Ahead of schedule...

Obviously, it's very difficult to do any recording at the moment but one of us has been managing to follow larvae near where he lives in West Sussex, and I'm just managing to keep tabs on some local ones here (and am also prospecting for habitat in my own parish, and finding it - the butterfly should be in the steep wooded upper Frome valley west of Cirencester...).

The news is that many larvae are feeding up rapidly in this dry April. Some had gone into the 4th instar by mid-April, which is the earliest I've recorded that life stage. Conversely, those on late-leafing trees are only just starting to feed now, though they will catch up.

At this stage, it looks as though the flight season will be early. It is possible that a few early males might even appear at the end of May...  Watch this space...  

Muscling In...

The Purple Emperor has the morals of an orc. This is illustrated by the following photo, which shows two males trying to muscle in on a mating pair.

The successful male is undoubtedly not without sin. The fact that the pair are mating in a sallow bush, rather than in the treetops, suggests that the male found a freshly-emerged and soft-winged female in the sallows, whilst sallow searching, and mated with her there and then, with little if any formality. Normally, she will lead her suitor up into the oak tops and they will mate there (for 3 hrs 30 mins on average).  

This amazing picture was taken in Theberton Wood, Suffolk, in July 2014 by Rob Reeve (thanks for sharing, Rob). It says an awful lot about this butterfly.

Incidentally, the FC will be thinning oaks in Theberton soon. Expect some changes...

Just when I thought PE larvae couldn't get any better...

New and more wonderful colour forms of hibernating larvae, from the Sussex woods, by courtesy of Ben Greenaway.

A half-black form, which you find on black-stemmed narrow-leaved sallows (I've seen it in Fermyn Woods).

A strange olive-green colour form, which I'd not seen before (out of >200 in the wild).

And a dull brown-grey form.

Most are in or by forks, or on old twigs scars. Buds aren't popular this year (I've no idea why).

Here's the Doings -

That's the good news. The bad news is that predation by tits during this absurdly mild 'winter' is ominously high, and February is the worst month for it.  

December Larval Survival

Mixed news here...

In and around Savernake Forest, Wilts, only one out of ten larvae succumbed to bird predation. That's Low, and a cause for optimism, suggesting that tits aren't going to home in on hibernating larvae there this winter (though the critical period is mid-Jan to late Feb).

However, Ben Greenaway, who is following an impressive sample of 30 hibernating larvae in Southwater Woods, West Sussex, lost seven to predation during December. That's worrying.  

Spot the 'pillar! (They rarely hibernate amongst lichens) -

2nd Brood Empress!

Believe this or not... A second brood Empress was seen flying low down and close to by a reliable recorder in woods near Milton Keynes on, wait for it, November 20th.  

As Fred Trueman used to say on TMS, "I don't know what's going off out there..."