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Strophedra weirana - New to Cheshire

Posted: Thu Nov 26, 2009 11:58 pm
by SteveMcBill
Strophedra weirana - New to Cheshire:

Hi All,

When out trapping with Mel Bellingham in Delamere Forest this summer (2009) I potted a dark brown tortrix which upon dissection proved to be Cheshire ’s first Strophedra weirana. The larva of this species feed between two or three Beech leaves, with one placed over the other, and held together by spinnings. This is illustrated on plate 15 in volume two of the Ray Societies book on Tortricidae. I’ve noticed these spinnings when out mining in the past but always dismissed it as S.weirana hadn’t been seen in Cheshire.

I was leaf mining across at Linacre Reservoir near Chesterfield on 13th October when I noticed the attached spun Beech leaves, which were tenanted, so I brought them home. It was not until two days later that I found time to inspect them again, by which time I was too late to photograph the larva. The Ray Society book mentions that “the spinning is characterized by the large amount of brownish frass scattered within.”. Also that it overwinters in a “frass-covered, tough silken cocoon spun up in the larval habitation which eventually falls to the ground”. As the description matched my specimen I sent the attached pictures to John Langmaid and asked him if anything other than Strophedra weirana fed like this on Beech. John replied “That has to be Strophedra weirana. The only thing that does a similar spinning is Diurnea fagella but .... the larva's a bit bigger!!!....”. Looking in MOGBI vol.4 (1) p109 Diurnea fagella pupates in cocoon in detritus or soil, Oct-Mar. So when on Beech you see similar spinnings, check that a frass-covered cocoon is present before recording Strophedra weirana.

Regards,

Steve Hind
Cheshire County Micro-moth Recorder