Monday, November 7, 2022

  My annual searches for autumn larvae are now complete. Larvae have been unusually - and worryingly - hard to find.

  For the last 14 autumns I have searched diligently, in a standardised manner, for larvae in Savernake Forest, Wiltshire. Larvae have been relatively numerous after all previous hot summers, and I was expecting to find them with some ease this autumn. 

  However, 2022 has been the second poorest autumn on record for larvae in Savernake, after 2020 (which saw an old fashioned wet July).  

  The same picture has been presented at my other monitoring sites, near Lambourn and in Cirencester Park Woods, Glos (a new colonisation).  

  It appears that something went badly wrong, something outside my previous experience - outside my box.  

  However, my searches are from the ground (I can no longer climb sallows due to arthritic knees) and my findings are based on the assumption that the females lay the same percentage of eggs low down each year - for which there's no evidence either way...

  Much depends on the Dangle Leaf season, now starting. I find this method about as effective as Floo Powder in Harry Potter, though it works well for Ben Greenaway on small-leaved sallows in Southwater Woods, W Sussex.  The dangles blow off on my large-leaved sallows (last late November, Storm Arwen took the lot...).  Ben is only just starting his searches now.  

  Worse, every early November I pray in earnest for cold, wet, miserable weather. This is the time when larvae are going into hibernation (diapause). They don't go far when the weather's poor. But wander far and wide in mild weather. Yet again, the weather's set to unseasonably mild during this crucial period.  

  A few larvae are already in hibernation, but the sallow leaves are staying on well in the absence of frosts. 

Here's 'Cruella', in hibernation on Sun Nov 6th:-

But 'Suella' was still only just starting to colour up (also yesterday) -

  This winter's 'Boris' and his counterpart 'Cincinnatus' are poised to quit their leaves, as is 'Lettuce Liz'.   

Watch this space...