Jacob Rees-Mogg

  This year's hibernating larvae are named after some of our politicians ('Donald', 'Boris', 'Margaret Hilda' etc.), so I wont be too upset if they get eaten by tits.  Here's 'Jacob', a lovely mottled grey form -

 Hello Purple enthusiasts,

Has anyone tried detecting caterpillars using fluoresence (as described here https://www.nightsea.com/galleries/caterpillar-fluorescence/)?

In my area, the density of Emperor caterpillar appears to be relatively low (I find one caterpillar every 2 hours on average). I am therefore looking for optimization techniques :-)

J.

Into Hibernation, via Dangle Leaf

Yet again, the weather's been ridiculously mild in early November, when Purple Emperor larvae were seeking to enter hibernation (or diapause, if you like). Some were crawling around for two or three hours, on different days, often ending up close to where they started. It remains to be seen whether they've wasted valuable energy reserves doing this.

To date, I have found 12 in hibernation, at two different sites. Interestingly, the five in Savernake went into hibernation a week earlier than the seven at Lambourn. Twelve is a reasonable sample size for monitoring winter survival, especially after a poor egg lay season.

I've named them after some of the politicians we all love so much (many of them will get predated by tits). Here's 'Donald', who spent more than two hours crawling around on Nov 9th, and moved again on the following day:-

He eventually conked out, curled around the underside of this thick branch, in a most unphotogenic pose.  

Most of the twelve are, as usual, aligned on narrow stems next to buds, like 'Nigel' here - 

But two are on well silked-on leaves - 'Boris' and 'Ivanka'. These are the first I've recorded hibernating on leaves in the wild (though Ben Greenaway had three do so last winter in Sussex, one of which survived). Here's Ivanka -

Note that she changed position by 180 degrees between Nov 2nd and Nov 16th.

Here's 'Boris', but he's difficult to photograph - 

And here's one of the loveliest 'pillars I've ever seen, the adorable 'Priti' - an unusual golden colour form conked out on the upperside of an old branch (+ lichens, moss & Veiled Liverwort). I don't think she'll stay there, as it's a very sunny position - 

Three of these larvae, including the adorable 'Priti', were found by Dangle Leaf - a technique for finding hibernating iris larvae by looking for vacated silked-on feeding leaves at leaf fall time, and then tracking where the 'pillar went. Ordinary leaves just fall off, but some of those that have been used by iris larvae remain attached, tied on by silk: the petiole itself breaks, as normal, but the leaf is then held on by the silk, and spins distinctively in the breeze. Here's what to look for -

I recently discovered iris in my local wood via Dangle Leaf. Ben has some success with it in Sussex, but it seems to work better with his Grey Willow hybrids than with my Goat Willow-type trees. There's an excellent German youtube piece explaining it:  https://youtu.be/5Yc4QDVg_wY

Good luck with Dangle Leaf, in sheltered places. This has been a very windy autumn and the Dangle Leaf Season may be short...

east midlands distribution map

 Thanks are due to  Derek, for uploading the map. Good to know that a word document cannot be uploaded to this blog: it has to be converted to a jpg file. 

The map shows Derbyshire [no sightings yet], Nottinghamshire [not many habitats yet, but spread across the whole county], and Leicestershire [a number of sightings, most concentrated within the National Forest area in the north-west of the county.

Gradual Northern Movement

 Since moving to Sheffield from Buckinghamshire, I have become increasingly interested in the appearance of HIM in all areas to the north of Rockingham Forest [Fermyn Woods]. I am grateful to my new friends from the East Midlands branch who have generously supplied me with data, in particular, Richard Jeffery, Ken Orpe, Suzanne Halfacre, and Jane Broomhead. Ken Orpe kindly generated this distribution map. 

Leicestershire has been particularly fruitful; in particular, the National Forest region has been very good for recorders with several new habitats having been registered. Nottinghamshire less so, but it is particularly exciting to announce  sightings, one adult and four larvae [two close together on one bush Matthew!], in Sherwood Forest. Matthew notes in his book that it was last recorded there in 1939.  Congratulations to Samantha and Nicholas Brownley, who made these observations, with supporting photos. With Chambers Farm Wood in Lincs, this is the most northerly known habitat. Of course, we cannot rule out releases being responsible for these sightings. 

Nothing in Derbyshire yet, but they are getting ever closer to the border. Ken Orpe will open a bottle of champagne when it happens!

I have not included Lincolnshire. HIM is well established in several woods south of Grantham, and in Chambers farm wood in the north of the county.

2021 Field Trails: Ready & Waiting

Well it has certainly been a while since I have posted anything here. Irrespective of this, much Apatura science has continued in the background and after 6 years of quite intensive science and investigation, I think we are finally ready to go live with Apatura attraction field trails next summer. I have now analysed Limburger and Pálpusztai cheeses, as well as Belachan and Shito pastes. I have also re-analysed Matthew and Niel’s Pantainorasingh plus Monika tiny shrimp mixture all by Solid Phase Micro-Extraction (SPME) Gas-Chromatography/Mass Spectrometry (GC-MS). The volatile analysis has identified one compound that is consistently present in all of these samples. The relative peaks relevant to this compound have been high-lighted with an anterisk (*). In addition to being found in these samples, the compound in question has also been confirmed to be present in all other known Apatura attractants inclusive of Dung (predominantly carnivore), Carcasses, Human skin volatiles, Cigarette smoke and Petrol fumes. The appropriate compound can also easily be explained in relation to the attraction of Apatura specimens which have been photographed clustered around the remains of a dead Rana frog. As predicted, the compound in question is a degradation product of a Branched Chain Amino Acid (BCAA), which have been confirmed to be readily incorporated into the male specific centrally methylated pheromone compound. As such, the males are being directly attracted to the site(s) of what they specifically need in order to produce their male specific pheromone. All I need to do now however is to wait until next summer in order to perform the field trials. It is going to be a long winter.

More Doom & Gloom

  For the last twelve years I've monitored the Emperor's performance in Savernake Forest, Wiltshire, by standardised searches for larvae during the late summer / early autumn period, from the ground. The data are shown in a table on Page 236 of His Imperial Majesty, a natural history....

  This is what I look for - 

  The 2020 tally is a mere nine. This is by far the lowest total in the 12 years. The previous lowest annual total was 16, in 2019.  The mean for the previous 11 years is 55 (the running mean is now 51).  

  This meagre total is entirely due to a very poor egg lay, as the adults got blasted away by gales in late June and early July - before they'd laid many eggs. 

The quality and quantity of the sallow resource in Savernake is actually quite high at present (though sallows close to Grand Avenue remain largely unsuitable as in dry weather their foliage gets covered in dust generated by speeding vehicles - Range Rovers and SUVs mainly; see Book, pages 236-237). There haven't been any problems with sallows droughting off in Savernake (though there have been in Sussex).   

  Ben Greenaway is finding a similar paucity of larvae in Southwater Woods in West Sussex, though he hasn't finished searching yet.  

  This means that the prospects for the 2021 Purple Emperor season are, at this stage, distinctly poor. But much depends on the winter, when larval losses can be high. The last thing we need is another mild wet winter (when mortality is very high).  

  Larvae are so scarce this autumn that I've had to abandon plans to search for Purple Emperor larvae in places where the insect hasn't been recorded for ages if at all, like the Forest of Dean, some woods in Herefordshire and into Monmouthshire, and Devon. I'm only prepared to launch a major autumn larval survey campaign in terra nova after a decent egg lay.

  Ben and I hope to have large enough samples of hibernating larvae to monitor winter survival rates, so we can compare survival / mortality rates between Savernake and Sussex.  

  I'll end with an image of hope. I found two larvae on the same spray on an isolated tree in Savernake which has revealed larvae in eight of the last 12 years. It is very rare to find two close by. 

These guys deeply resent each other's presence: one will periodically invade the other's seat leaf, where they will lock horns and try to wrestle each other off. Ridiculous, but that's Emperors all over.