This fly causes galls to form on Yew (Taxus baccata). Similar to the 'Artichoke Gall' encountered on Oak, this gall comprises of 60 - 80 terminal leaves that become clustered to form a single gall whose outer leaves are dark green and the inner ones almost white. The galls eventually turn brown and can stay on the plant right through to the next year.
Each gall contains a single orange-red larva that feeds within the gall after a resting period and then pupates inside and emerges as an adult about 1 month later.
Occasional in England and Wales, but may well be quite common and under recorded.
There are few records from our area, but this is probably due to under recording.
Leicestershire & Rutland Map
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Yellow squares = NBN records (all known data)
Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015