|GALL INDUCING FLIES|
|When I saw plant galls for the first time I wanted to know what species there were to be found basically, and so I started collecting anything that looked like a plant gall. Boxes full of them I have now. Nowadays I think it is better for me to take pictures (digital or slides) and when you are interested in the gall maker itself, it is a good idea to try to get the inhabitants to emerge from the galls. The list of species described below are gall makers and their hosts, from species that I myself or another gall studying person has seen. A description is given and, where possible, a picture. For people who are interested in the Dutch distribution of pant galls can soon take a look at the database we are preparing for this website. Since the subject of plant galls becomes more popular only recently, we do not have yet such an extended database. Any contribution is welcome!|
|Chirosia betuleti is a fly of the Anthomyiidae, causing the tip of the frond to get rolled upwards in a loose, collection of pinnae (Redfern et al. 2002). Inside lives a white maggot that mines along rachis causing it to coil. The gall is not very rare, but not so common.||
(Picture: J. Wolfs)
species occur on Phragmites australis, Reed. Galls of Lipara are
most easily found in patches of reed than grow under less optimal conditions,
like the less wet areas near water.
Lupara lucens, is shown on the pictures and is thought to be the most common of the Lipara species. She causes the thickest gall of all the Lipara species in the Netherlands. Galls are sometimes predated by birds, like great tit.
Besides Lipara lucens, there also is Lipara pullitarsis, and Lipara rufitarsis.
(pictures: B. Kabbes)
cardui is a fly that causes spectaculair deformations of the
stem of Cirsium arvense. The gall has a very compact internal
structure and there are several larvae in one gall. The gall is often
positioned on the dividing branches or in the top end of the plant.
In case of the latter the formation of flowers is prevented due to the
galling. The galls are round and elongated, strait or bended. They are
between 6-50 mm long and 4-20 mm in diameter. Inside the larvae chambers
are irregular and the larvae are white of colour. The gall starts with
being green and shiny, but later turns brown and more hard. The maggot
transforms inside the gall. Margaret Redfern explained how the larvae
are able to emerge from the galls: "Urophora cardui larvae
cause chambers that are not sealed over - a tunnel to the
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