Thursday, May 29, 2014

Held Back!

The last week of May is one of the key weeks in the butterflying calendar, only this time the weather's been foul.  Purple Emperor larvae have scarcely grown since my last post - which is perhaps a good thing as they were ridiculously advanced and actually needed slowing down.  A visit to the Savernake area on Sat May 24th found that most of the few surviving larvae were 2-4 days off from pupating, like this one -

However, there is one runt, who was only just changing into the 4th instar.  This larva was on a tree that was felled during the winter.  It wasn't dislodged when the tree crashed down.  I left it to see how it fared, but then moved it on April 21st when it became clear that the tree wasn't going to come into leaf.  So I pet rescued the poor fellow, whilst it was still in hibernation (late), and placed it on a nearby young sallow.  I think it only commenced feeding at the end of April.  Here it is, skin changing to the 4th instar -

My prediction now is that iris will start to emerge around June 20th, but much depends on June weather as the insect spends ages in the pupal stage if the weather's poor. 

I am not optimistic about adult numbers this year, having recorded record levels of predation this winter (from a sample of 63 larvae) and having had a surprisingly high number of larvae vanish during April and May too.  Much depends on June weather and, especially on flight season weather, but I fear that iris will be relatively scarce this year.  Hopefully I have got this terribly wrong, in which case I will post a selfie of me eating my hat...

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