Two-thirds of the way through my annual survey of iris breeding sites in / around Savernake Forest and it looks very much as though this year will prove to be the poorest in six years of systematic recording.
To date only 16 breeding sites have been found - that's both live larvae and failed breeding sites (i.e. definite vacant larval seat pads + egg case bases, and no sign of the larvae anywhere).
Worse, only five live larvae have been found - along with 11 failed breeding sites. That is an unusually and worryingly high proportion of failed larvae, usually it's the other way round. I will look around the failed sites again, as one or two larvae may yet be located - they can wander quite far, especially just after the second skin change (yesterday I found a third instar larva 2.5m away from the egg case base and 1st / 2nd instar feeding leaf, but they can travel much further).
Perhaps the cold, wet August (memorable for ex-Hurricane Bertha sitting over us for a week mid-month) caused high mortality. However, I strongly suspect that the bulk of these disappearances result from mortality due to unsuitable foliage: early springs produce leaves that are too thick, coarse (dark-leaved to our eyes) for young larvae in late summer. Certainly, there is a shortage of the favoured 'mid-green soft matt leaves of medium thickness' around this early autumn.
Of course, all this is based on the assumption that the females consistently lay low down from year to year. They may, or they may not... the minxes...
Finally, a plea to support Paul Fosterjohn's production of a badge showing a Purple Emperor larva and the Never Underestimate a Caterpillar motto (in English and Latin). Paul needs more subscribers. Details -
This is a crowd-funding initiative in that I need 40 orders placed within a month before I go into production. I am looking for each person to order at least one pin badge and send me a cheque for the amount of £5.50 per badge with an additional £1.20 for postage (for up to four badges). I will bank all the cheques on the 4th of October ONLY IF 40 orders have been received.
I particularly want this badge...