Tuesday, November 1, 2011

Yew Midge Gall

This year some of the yew trees in Teesdale are heavily infested with this 'artichoke' gall, caused by a tiny midge called Taxomyia taxi. This insect has a strange two-speed life cycle. Eggs are laid on the yew shoot tip foliage in late spring, inducing the formation of a swollen terminal bud where they spend the winter. Some emerge as adults in the following year but others, like his one, have slower development and spend a second winter inside an enlarged and more conspicuous gall before emerging as midges two years after the eggs were laid.

Margaret Redfern's recent New Naturalist book, Plant Galls, is a mine of information on the strange world of these plant-insect interactions.

7 comments:

  1. Well blow me down! I've seen this and just thought what the hell..........thanks again.

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  2. I am fascinated by galls and all their variations. I've never noticed this one. Must take the camera out to the park and see if we've got them here.

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  3. Having commented on your blog for a while I've just found your other blog. I recall the name Phil Gates from my time being involved with various natural history groups on Merseyside - would that be you or simply a coincidence of names? Scriptor Senex - aka John (formerly Clive) Edwards.

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  4. Hi Adrian, i think you only really notice them when there are a large number on a single tree

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  5. Hi John, I was first introduced to galls by a wonderful naturalist called Fred Stubbs who lived in the dales in North Yorkshire - he produced one of the first affordable ID keys and helped start the British Plant Gall Society which now has a very useful web site at http://www.british-galls.org.uk/
    It could be someone else of the same name that you remember, although I was involved for many years with natural history groups like the Northern Naturalists Union on this side of the Pennines, and have written quite a lot for natural history magazines. All the best, Phil

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  6. I shall take myself off to the local churchyard and have a look there.

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  7. Hi toffeeapple, make sure you choose a tree that hasn't been neatly clipped..

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