Skin Changing!

Am rather chuffed with this pic of a wild cattie finishing changing skin to L3. The cast skin is bottom right of his tail end, the horns from his cast head are above the new head (15 seconds later they fell off). Imagine getting a new head!

The whole process took just one minute, at 2.52pm on Sat Aug 22nd, near Lambourn, temp. ca 23C, with the 'pillar in sunshine. There was a lot of head waving at first.

S/he will wear that skin and head until April...    

 

Larval Numbers: Update

Although the 'egg lay' has been huge (i.e. the females weren't sitting around watching daytime TV and painting their fingernails, but have laid a lot of eggs), it is clear that there has been an unusually high mortality rate amongst 1st instar (= baby) larvae.

In and around Savernake, and elsewhere, we have recorded a 1st instar mortality rate of about two-thirds, from a decent sample.  

This means we are finding a lot of 'L1 Fails'; i.e. single leaves bearing the distinctive feeding marks close to or, better, either side of an end-of-leaf larval silk pad + isthmus. Like this - 

Here's one with the egg case (by my thumb, the vacant seat pad is to the right, and has shrivelled) -

Often, the seat pads aren't that distinctive, or the feeding isn't, in which case you need to find the egg case base (or ECB for short) to be sure. 

I have not recorded a higher loss rate amongst L1 (1st instar) larvae, though L1 losses were high in the thundery heat of 1976. 

It looks as though a great many of them succumbed to the heat, and desiccated. Some, though, will have been predated, though invertebrate predator numbers seem to be relatively low, again due to the heat (I can't monitor invertebrate predators, it's too difficult). E.g. social wasp numbers crashed in mid-July.  

We have even lost some early 2nd instar larva to assumed heat desiccation. I have not recorded this before, though Dennis Dell has in Switzerland, which is prone to hotter weather. 

However, we haven't lost any young larvae to heavy rain wash-off, which happened in 2018, and even in 1976. We haven't had any thunderstorms. (L1 larvae are vulnerable to thunderstorms).

All this may mean that predation by titmice during the winter may be lower than it would have been...

Here's what we like to find, a healthy L2 (2nd instar) 'pillar -

I have also recorded Savernake's earliest ever 3rd instar larva (L3), on August 14th.  

Finally, sallow foliage quality is wonderfully high this year, without any of the Willow Rust which rampaged throughout the western reaches of the Empire during 2023 and 24, and hardly any Sallow Mildew (another problem, in damp summers). 

This does mean, though, that there's an awful lot of foliage to be searched...

Onward, towards the 2026 Purple Emperor season!

Excerpt from Oates' Diary: Sun June 29th 2025

Knepp - 

Bentons Gorse W Side: Rosemary’s Tree 5.10 – 6.55.  Big and overdue session here, and a deeply memorable one.  I needed to make up for missing out on the teenage jackdaw-chasing episode here last Friday, which had Neil and Kat rolling around in laughter (several Emperors terrorising a flock of young 'daws).  I did make up, and with Neil. 

Things started off with a brace of males sapping on a low horizontal SW side oak branch, and 2-3 others flying about higher up, and deteriorated nicely from there. 

5.20.  A female panicked after failing to shake off 2 over-amorous males through a tumbledown, and hurtled off south along the oak edge, zig-zagging and alternating high and low.  Eventually they went off squabbling and she escaped.  I wouldn’t like to be a female Purple Emperor…

Then, a vista of five males in the air at once, all oak edging separately. 

5.27.  Six in a vista.  3 males feeding well apart on the favoured horizontal bough, plus two males mucking about and another trying to come in to feed.

5.30.  4 males feeding separately on the favoured branch, 3 in perfect condition, one frayed. 

5.44.  Female on the feeding bough, plus 3 males and a Red Admiral, but problems with hornets. 

6pm.  Seven males in a vista around Rosemary’s Tree. 

6.03.  Six males feeding along a 3m length of bough. 

6.05.  Ten in a vista!  8 males feeding loosely along the branch length, two in flight nearby, plus a Purple Hairstreak and the hive bee-mimic hoverfly Brachypalpus laphriformis feeding on sap bleeds.   

6.20.  OMG!  A fresh (Neil thought female) Large Tortoiseshell flew in through the tree, to settle and display on the barkless dead branch rising vertically off the main feeder branch.  We both managed to get token photos before it got disturbed by hornets and was then chased off south along the oak line by two irate Emperors.   When were Purple Emperors and Large Tortoiseshells last seen interacting together in Britain? 

6.25.  Excellent tumbledown involving a fresh but mated female and two Andrew Tate males. 

6.40.  Female being hotly pursued around Rosemary’s Tree by 6-7 males, but they were too frenetic to count.  Then things went quiet. 

6.55 – 7.05.  When leaving, I counted 22 males along the whole quarter mile west edge of Bentons Gorse. 

Ambition: we want people to be able to have similar experiences with this butterfly all over England, and Wales, and Scotland.