Galls: Taxomyia taxi

09 Thursday Feb 2023

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Artichoke gall, fly gall, galls, galls on Yew, insect galls, midge gall, Taxomyia taxi, Yew

My Field Studies Council Guide to plant galls in Britain explains that the gall midge Taxomyia taxi actually causes two types of gall on Yew trees. The least common, which looks just like a swollen bud, completes its life cycle in one year – I’ve yet to find any of these. But I was very pleased earlier this week to locate several examples of the artichoke gall, in which the same midge completes a two-year life cycle. Eggs are laid in May/June, the larvae crawl in to a leaf bud and stay there, barely growing, until the following summer. At that point, they grow rapidly, over-winter again as larvae, before pupating and hatching the following May. I couldn’t find any explanation for the different life cycles.

230209 taxomyia taxi

Not wanting to kill the creatures inside, I haven’t opened up any of the galls I’ve found but, if you’re curious, as I was, about what’s inside the artichoke, the Plant Parasites of Europe website has some excellent images of the larva, the pupa and the adult fly.

Dasineura fraxini galls

03 Wednesday Nov 2021

Posted by sconzani in insects, leaves, trees

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Ash tree galls, Dasineura fraxini, gall causing midge, gall midges, galls, galls made by midges, galls on Ash leaves, midge gall

One of the benefits of checking the leaves of various trees, and other plants, for leafmines is that, even when I don’t find them, I do find other things just as interesting, and this is one of those. I didn’t know what it was, of course, until I got home and checked my Field Studies Council Guide to plant galls in Britain fold-out guide. (If you’re not familiar with these, check the FSC online shop here. I have a few of these and find them really useful.)

My guide informed me that these galls on the leaves of Ash trees were created by the larvae of Dasineura fraxini, a species of tiny midge. Few people have ever seen the adult midge but I did have a look at one of the galls that was partly open and spotted one of the miniscule orange larvae. These galls can be found from May through to October, at which time the leaves will fall to the ground, where the larvae will pupate and over-winter until emerging as adult midges in the springtime.

211103 Dasineura fraxini (3)

238/366 Midge galls

25 Tuesday Aug 2020

Posted by sconzani in autumn, insects, nature, plants, wildflowers

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British galls, British insects, British wildflowers, Cosmeston Lakes Country Park, galls on wild carrot, Kiefferia pericarpiicola, midge gall, Wild carrot

I was looking around at the various wildflowers yesterday at Cosmeston, seeing what insects might be about, when I noticed these odd growths on some of the Wild carrot flower heads. I split one open with my finger nail and a miniscule orange blob fell out; turns out that was the larva of a midge with the long-winded name of Kiefferia pericarpiicola.

200825 Kiefferia pericarpiicola (1)

The galls start off green (below left), before turning pinkish and eventually brown. According to the Nature Spot website, these galls can be seen from late summer through to autumn, after which the larvae will leave the gall and drop down to the soil to pupate. The midge only occurs in southern parts of Britain at the moment – and I only found two previous records in the Welsh biodiversity database – but perhaps that will change as our climate continues to warm and the midge flies further afield. It’s also possible, of course, that this insect is under-recorded – it seems the midge itself is almost never seen, only its gall creations.