Friday, April 17, 2009

Breeding Log of Two Apatura iris by IRP Oates

On 3rd August 2009 two ova of A. iris were found on female Salix caprea trees, somewhere deep within the heart of the Purple Empire. They were found by searching with a tall step ladder, but you don't need to know that.

They were hatched indoors, and the larvae taken through their first instar there, before being placed outside on a sleeved potted sallow (S. caprea) in my garden on the Gloucestershire / Wiltshire border. This proved wise in what was a Foul & Abusive August. They were named Fred and George, you can work out why for yourselves.

They fed intermittently, mainly during the late afternoon or early evening, before bedding down for the winter. During Sept and Oct they often went days without doing anything. The truth is that rearing iris larvae during late summer & autumn is almost as dull as rearing those of the Brown Hairstreak Thecla betulae.

They changed colour slowly during late October and went into hibernation in mid November, initially on withering leaves. On 15th Nov Fred moved to take up a position next to a prominent upper bud, and stayed there all winter, wisely comatose. George had a crawl round on 16th Nov but then returned to his curled up leaf, where he conked out for the winter. Oh that we could do likewise! The leaf remain attached all winter.

Both gradually changed colour, to green, during late March, having not stirred all winter. On 30th March, George moved to take up a position alongside a swelling bud. He started feeding on 5th April, ahead of Fred - whose bud proved to be slower in opening. Both were feeding on 6th April, close to their winter pads. George fed initially from the leaf's underside, which is unusual.

Because the sleeve was placed in the shelter of a beech hedge the sallow did not come into leaf early, so Fred & George had to hang about a bit, waiting for the leaves to unfurl. The leaves did not unfurl properly before mid April.

On 14th April, George was on guard, hunched on a leaf, but Fred was resting up by day on his/her winter pad on the stem. Fred moved to a leaf pad the following day. By the 17th, each had consumed a single whole leaf. That night, most of the drain covers along the 17 mile route between their village and Swindon mysteriously disappeared - something to do with the high price of scrap iron - it's amazing what goes on when you're rearing iris.

I am now quitely confident that Fred & George are going to fly. They've got through the tricky late winter period, when larvae can just wither up and die (it's most distressing: I once lost James & John the sons of Zebedee in that manner). Watch this space: nothing might happen, but watch it anyway.