Nature Notes from Skye
(and occasionally other places)
Fri 16 - Sun 18 Sep 2005 Doncaster (Part 4)
Galls on herbaceous plants
Two galls on Fireweed; these will be well worth looking out for back home as we have plenty of the host plant. The first is a stem swelling containing the moth caterpillar Mompha nodicolella, and the second a leaf-roll due to the gall-midge Dasineura kiefferiana.
The work of the jumping plant-louse Trioza urticae on Stinging Nettle, and that of the gall-midge Dasineura serotina on Perforate St John's Wort.
Two more leaf-crumplers. Galls of the aphid Brachycolus stellariae on Lesser Stitchwort, and the gall-midge Macrolabis heraclei on Hogweed.
A stem swelling in Common Catsear caused by the gall-wasp Phanacis hypochoeridis. This can contain up to 50 larvae, each in its own chamber. The left-hand dead head of the Spear Thistle has the receptacle and achenes converted into a woody gall of the tephritid fly Urophora stylata.
The two common galls on Burdock are both caused by tephritid flies. The first is found by looking for an achene with a hole in the top end. Here part of the achene is removed to show the larva of Terellia tussilaginis (sorry for crummy picture). The second is the larva of Tephritis bardanae which eats the flowers and causes the receptacle to form a thick callous, in which it eventually pupates.
Yet another tephritid larva, Urophora jaceana, in a hardened section of a Knapweed flowerhead. The purple swellings on the Sow-thistle leaf contain larvae of the gall-midge Cystiphora sonchi.
Two galls on Mugwort now. First, the tephritid fly Paroxyna misella, which causes a stem swelling beyond which the plant does not grow properly. The second, the dark swelling on the upper of the two leaves over the ruler, was thought to be caused by the gall-midge Rhopalomyia foliorum, but this awaits confirmation.
More gall-midges. Dasineura trifolii causes the folded Clover leaflets on the right of the first picture, compare normal leaflets on the left. Dasineura viciae causes the folded leaflets on Vetch. We also saw Dasineura spadicea, which I showed on the Bettyhill pages, on Tufted Vetch, and probable Dasineura loewiana on Hairy Tare, but I can't make out which bit is the gall in my picture of that so I'm leaving it out!
The imposing larval home of the gall-midge Contarinia loti on Greater Birdsfoot Trefoil. Centre pic shows the Lighthouse Gall, Rondaniola bursaria, on Ground Ivy, also made by a gall-midge. The RH pic is not of a gall but is of a gall-causer. It shows the rust fungus Coleosporium tussilaginis on Eyebright. We previously had this from Skye on Butterbur. It does not gall that plant either, but it does cause a gall when it occurs on Senecio species, while its alternate generation galls Pines.
A gall on Reed caused by the gout-fly Liparia lucens. It causes the stem to thicken and growth to cease beyond that point. The RH pic shows the grass Phleum bertolonii (Lesser Catstail) with shortened, distorted and purple internodes. In one area of a field there were many like this while in other parts of the field all the plants were normal. There is no known gall of this type and eventually it was decided that it was just an unusual growth form, but it looks very odd.
The overlap between the galls seen in Doncaster and those seen in Bettyhill was virtually non-existent. The only ones I have notes of from both places are Dasineura spadicea and Iteomyia capreae, though there may have been one or two others that I didn't bother either photographing or jotting notes on because I knew them from Bettyhill or Skye; can't recall any though. Doncaster and Bettyhill have very different floras of course, but even on species common to both places, such as Nettle, the galls were nearly always different.
Part 5 consists of species other than galls or flowering plants.
All photos and other content copyright © Carl Farmer