Progress Report...

This is is an unusually wet May, and Purple Emperor larvae get held up badly by wet weather. They don't like wet foliage, though they are adept at making the most of dry weather windows, feeding up fast when the foliage is dry. Wet (and cold) weather holds up skin changing, which in months like this can take well over a week.  

One of my wild larvae, 'Boris', seemed to be about to start skin changing (to L4) on May 9th and was stuck changing on May 22nd. Here he is, taken yesterday:-

All the other larvae seen yesterday were in the mid-L4 stage, including one who was still in hibernation (though green) on April 30th. He's since caught up spectacularly, and has overtaken 'Boris'. 

All this means that wild larvae are not behind schedule - yet. The season is actually tracking that of 2010, when the first Emperor took to the air on June 26th (after a good June). Here's a typical mid-L4 larva, from yesterday:-

This is the infamous 'Priti', and she's on the march... Be very worried... 

Late May is a key time of year for Emperor larvae, with them feeding up in their final instar and preparing to pupate. It looks as though the weather is going to improve after tomorrow (it can hardly get worse...) - in which case, they'll catch up fast...

Provisionally, I guess that the first male will be seen on June 26th, but I'll make my formal prediction at the end of this month, as usual. But please don't think that Emperors wont start before mid-July this year - at least, not yet....  Neil's going for June 28th, at this stage. 

Watch this space... ... ...  

For the record, of the 20 larvae I have followed since last autumn, six are still extant: 'Boris', 'Jacob', 'Liz' (Truss), 'Margaret Hilda', 'Sir Nick' and 'Priti'. I may yet refind one or two others, notably Andrea (Leadsom). Winter larval survival was relatively good, though at least three were predated during the cold April, including 'Donald', my favourite.

Skin Changing

Purple Emperor larvae continue to develop slowly, held up by cold weather and now, by rain (which is probably a greater hindrance to them).  

At present, early larvae have just entered the 4th instar (L4) and the majority are skin changing, or about to. This means that they are not yet that far behind the modern norm, but a wet May (which seems likely) will delay them significantly.

Rather chuffed to witness a skin change yesterday, and manage to photograph it (note the wobbly horns) -

Unfortunately, I lost a few wild larvae during April (and early May) to predation. This is annoying as my winter larval survival rate was 60-65% (depending on whether I refind one missing 'pillar), which is the best I've recorded from a decent sample size. This suggests that 2021 could yet see a good emergence - but a great deal depends on June weather...

Watch this space, and enjoy the Painted Ladies, which have just arrived...

 

Slow Spring Progress

Purple Emperor larvae are developing slowly in this cold, late spring (I recorded frosts in my garden on 27 nights during April). 

One larva in Savernake Forest was still on its winter hibernation pad on 30th April, though it had greened up nicely and would have found eadible leaves within half a metre had it bothered to move (oddly, it is in a south-facing position).

Most wild larvae have fed a fair bit, post-hibernation, and will be seeking to change skins into L4 within a few days. This means that they are not that far behind the modern norm. The three I have in captivity (an outdoor sleeve) are all skin changing now, as are one or two early-birds in West Sussex.

Nomally, Emperor larvae are held up by early spring rains - but this time it's cold drought...

I'm not yet able to give a final reading on winter survival / predation percentage, and wont now be able to before mid-May. However, the predation / loss rate is likely to be between 40-50%, which is actually about as good as it gets (last year the winter loss rate in W Sussex was 85%). 

Unfortunately, though, both Ben Greenaway in W Sussex, and me in N Wilts & SW Oxon, seem to have lost some feeding larvae during April, to predation. We may yet refind some of these lost souls, as post-hibernation L3 larvae can at times wander quite far (I've recorded 6m, but 1m is normally plenty). Sadly, at this stage 'Donald', 'Priti' and 'Andrea' (Leadsom) are missing-presumed-crunched. They have a huge following on Twitter.

But 'Boris' and 'Margaret Hilda' are feeding well, and are set to change into the 4th instar very soon (weather permitting). Here's 'Boris' from April 30th:-

The question readers want answering is when will iris start to emerge this year? That's always hard to answer before late May but at this range it's unlikely that the butterfly will start to emerge before June 21st this year - but a warm, dry May could bring that forward.  Watch this space...

Useful aid to finding pupae: UV Fluorescence

I have previously documented that Apatura larvae unfortunately do not fluoresce under UV. Whilst recently digging through some older literature: THE BOOK OF BUTTERFLIES, SPHINGES, AND MOTHS; (VOL. I), THOMAS BROWN (1834), I came across a statement under a section on the "Purple Highflier" which described the Apatura pupa as having a "very delicate texture, much resembling the white pupa, and is tinged in several parts with a very lively purple hue, which is transmitted from the wings of the enclosed insect". With this statement in mind I turned my attention of UV light to the pupae and discovered to my surprise that although the larvae do not fluoresce under UV, their pupae certainly do and shine like luminous beacons in the night. This is without a doubt due to the white waxy coating that the pupae possess and could prove to be a very handy tip for finding specimens out in the field.

First Baiting Reports & Attraction to Dung/Carcasses?

Dear All. Considering the extensive amount of Apatura knowledge here, I was hoping to please try and tap into this in regards to a simple question/query. I am please looking for the earliest recorded literature on his majesty's attraction to dung and/or carcasses. My own hunting has so far identified a letter posted by William Sturgess in Vol.2 of the Entomologists' Weekly Intelligencer (12th May 1857), where he reports their attraction to Stoat and Weasel carcasses. By 3rd August William had used the same technique to note the attraction and capture of 80 specimens. In the 1830's capture of the Purple High-flier could only be obtained using long poles, but by the 1890's baiting using carcasses was common practice. Does anyone perhaps please have any recorded literature that pre-dates this post by William Sturgess (12th May 1857)? Many thanks for any kind help in advance. Mark

Aberation from 2019

hi, I posted an aberration from 2019 on this blog. I think someone told me it was ab. afflicta but I'm not sure. Is there someone who really knows their (purple) onions confirm please?

My original post is here.

http://apaturairis.blogspot.com/2019/07/var-afflicta-at-bernwood-bucks.html

Winter Ending...

  Purple Emperor larvae are now all out of hibernation and are lined up alongside swelling buds, ready and waiting to start feeding. 

  One of two have had their first bites out of loosening buds, but as a whole they are stuck in what I call the Departures Lounge, waiting for the sallow leaflets to expand sufficiently. 

  This is a frustrating time of year for them, not helped by cold nights. They wont make much, if any, progress this week, due to the forecast Arctic winds and cold nights. The sallows are progressing very slowly, and are taking an age to flower this year (leaves follow flowers...).   

 It is still too early to give a winter survival rate, we have to wait till they start feeding properly. However, I'm sure we can say that the survival rate is significantly higher than during the 2019-20 winter (unless mass predation occurs this week). 

  In West Sussex, Ben Greenaway seems to be set to record around 40% survival, compared to a mere 15% the previous winter. 

  In the N Wilts district, I seem to be set to record 50%, possibly 60% survival - but will have to wait until late April before I can locate a couple high up on sallows (spotted through binoculars, but now masked by sallow flowers). This is about as good as it gets.

  At this stage, we can say that 1) larvae are currently somewhat behind schedule but that 2) their spring numbers are relatively and pleasingly high, so 3) we could be set for a good emergence, probably from late June.  

Watch this space...

Here's some recent (early April) photos of larvae - 

Fans of my named larvae (see my Twitter account @MatthewOates76) will be pleased to learn that Boris, Donald, Andrea (Ledsom), Jacob and Margaret Hilda are all alive and well - indeed, Margaret has started to feed. But Ivanka, Nigel and Sir Nick got crunched. 

  PS Hau Loc shrimp paste is back on sale in the UK, post Brexit (the EU banned it as unfit for human consumption). This is by far the best brand of shrimp paste for iris. See https://asianfoodie.co.uk/dry-store/condiments. This is why we voted Leave...