Sunday, August 31, 2014

Woe, and thrice Woe!

My first full search for larvae in / around Savernake took place yesterday, accompanied by Ian Shale.  In 4hrs 30 mins searching we found signs of three larvae, only - egg case bases and 1st instar larval feeding leaves + silk seat pads, two of them with 2nd instar feeding leaves too.  But no attendant larvae.  Presumably, these had perished.

The tiny egg case bases can last for weeks - last year I found one in early November.  But the larva eats the bulk of the egg, leaving just the glued-on base behind, like this:-

The larval feeding leaves + seat pads are quite salient by late August, hence why I prefer to look for 2nd or 3rd instar larvae, rather than eggs.  They look like this:-

This is a dismal tally, given that we searched much of the traditional main breeding area.  Last year the same trees produced nearly 50 larvae!  Part of the problem was that frog-hopper nymphs had devastated much of the foliage, and iris females avoid such trees.  Also, the early spring had led to the development of coarse, thick and dark leaves, which are generally avoided.  I realise why I saw just a lone female in that part of the forest this flight season.

The hunt is now on to find where the females laid their eggs...

Watch this space, but at present the prospects for 2015 look distinctly bleak!

1 comment:

dennis said...

even on 'good' sallows, with little frog hopper nymph damage, were larvae not found by me!