Tuesday, May 31, 2022


   The current cool weather has slowed larval, and doubtless pupal, development right down. This means that the flight season may well not start before mid-June now (and the weather may worsen over the Jubilee weekend, given the track record of jubilee weather...). 

  The three larvae I have in a sleeve in my garden have virtually stopped developing altogether, but we've had night temperatures as low as 1C (on the last two nights)! They're full grown, or thereabouts, but need warmth to start to pale up and begin the process of pupation.

  Likewise, the larvae I'm following in my local woods (Boris & Co) have slowed right down, with the exception of Priti and Liz who are late developers, now catching up.

  My guess is that some larvae pupated in the Southeast over the warm weekend of May 21st-22nd, possibly one or two before then. In theory those could start to emerge as butterflies circa June 10th, but they're very few of them and may not get seen. We could be in for a longer than normal flight season. And there could be a goodly number of aberrations around, due to cold nights producing cold shock on newly formed pupae. 

  Cool weather slows pupal development right down, and we know that the longer the insect stays in the pupal stage the fewer adults fly, due to increased mortality. The future of the 2022 Purple Emperor season hangs in the balance.

Watch this space...

Here's Jacob from May 29th -

Stuck on his seat leaf waiting for it to warm up...

Friday, May 27, 2022

The 2022 Purple Emperor Season

 Unless the Platinum Jubilee generates the traditional foul & abusive jubilee weather we are set for a very early Purple Emperor flight season, and quite possibly an extremely good one.

I was going for a 1pm start on Thurs June 9th but the last week of May, a crucial period in determining our Midsummer butterflies' appearance, has been cool, especially at night. The 9th is still a distinct possibility but the weekend of the 11th-12th is now more likely. I'm going for 1pm on the 11th.

Neil Hulme is predicting the 15th, as "we're bound to get some poor weather" and Ben Greenaway is going for the 13th.  

The official record for the earliest UK Purple Emperor is 10/6/1893, though in that exceptionally hot summer it was 'out in the New Forest by early June' - whatever that means. The modern record is 11/6/2017 and 11/6/2019.

Those records could well be broken this year. 

However, each year we receive claims of very early Emperors from strange places by people who are not known to be official Emperorphiles. I'm sorry, but it is hard to accept such records. If there's a smidgen of doubt, don't claim it: genuine Emperor sightings leave you in no doubt whatsoever... (and this applies to me too).

Although much depends on weather during the pupation and pupal stages (more so than flight season weather) this summer could well see a distinctly large emergence - this could be an all-time great Purple Emperor year.

Meanwhile, here's Boris the Emperor caterpillar, taken the other day. He's full grown and ready to pupate, and he's in the sunless wastes of Gloucestershire. As has been written large on a bridge over the M4 at Bristol: Boris Is Helch - 

For regular updates on Emperor affairs follow me on Twitter @MatthewOates76

Wednesday, May 11, 2022

Early Season Likely...

 A quick heads up to say that Purple Emperor larvae are developing rapidly in this fine spring. Some are already entering the final instar. That's very early...

As things stand, we can anticipate the flight season to start in (or even by) mid-June, and for it to be over by, say, July 21st.  

I will post my official prediction for the start date in a week or so's time. 

Expect, though, extreme weather at and around the time of Her Majesty's jubilee - given that the seven royal jubilees held to date have all generated extreme (and mainly bad) weather. That may delay the flight season. 

Also, this could be an extremely good Emperor season, though much depends on weather during the pupation and pupal periods.