Nature Notes from Skye
(and occasionally other places)
Fri 16 - Sun 18 Sep 2005 Doncaster (Part 3)
Galls on other trees and bushes (see part 2 for galls on oak)
Two mite galls on Beech. Aceria fagineus causes roundish brown hairy patches between the veins on the underside of the leaf, while Aceria nervisequus causes elongated ones along the veins on the top side of the leaf. The mites live among the hairs.
Acalitus stenapsis is another Beech mite, that causes the leaf edge to roll. Hartigiola annulipes is a gall-midge that causes tall pimples on Beech leaves.
Two Ash galls now. Dasineura fraxini is a gall-midge that causes a pouch on the leaflet midrib, and Psyllopsis fraxini is a jumping plant-louse whose larva lives in a crumpled leaf-roll.
Two mite galls on Maple, Aceria macrochelus and Aceria aceriscampestris.
The Rivet Gall, Didimomyia tiliacea, on Lime. This consists of a roundish outer gall, and an inner gall shaped like a rivet which fits inside the outer gall. The rivet contains the gall-midge larva and eventually falls to the ground, leaving a hole which gradually grows over on the upper side. The top picture shows the upper side and the bottom picture the lower side, after the rivet has fallen. The RH pic shows the leaf-roll caused by the mite Epitrimerus trilobus on Elder.
Not a rust fungus but the hairy erineum caused by the mite Eriophyes malina on Apple leaves. A related mite, Eriophyes convolvens, causes these leaf-rolls on Spindle.
Acalitus brevitarsus, a mite gall on Alder. Like many mite galls, the leaf is made to grow clusters of hairs, called an erineum, among which the mites live. In this species, the hairs have several near-horizontal branches at the tip, so that each group of hairs is like a forest with a closed canopy. The close-up picture shows how dense this canopy is although you can't see the individual branches. It seems incredible that a mite can get its host plant to grow such a highly-specified structure tailored to its needs.
Pontania proxima on Crack Willow or Crack x White Willow. The RH pic also looks like a Pontania gall, but it isn't. It is hard and woody and is apparently Rabdophaga salicis, normally found on stems or twigs but here, very unusually, occuring in a leaf midrib. There were several other R salicis in the vicinity in their normal positions.
The Hawthorn Button-top Gall, caused by the gall-midge Dasineura crataegi. On the right, "Pocket Plums", Blackthorn fruit swollen and distorted by the fungal gall Taphrina pruni.
This rose leaf had been entirely eaten by some creature, apart from the midrib and the gall of Diplolepis nervosa, which was obviously not to its taste. Another gall-wasp, Diplolepis rosae, caused this hairy red Robin's Pincushion or Rose Bedeguar Gall.
Two gall-midge galls on Bramble. The stem swelling contains several cavities, each lined with fungal mycelia on which the larvae of Lasioptera rubi feed. The leaf creases form a home for the larvae of Dasineura plicatrix.
On to part 4, galls on herbaceous plants...
All photos and other content copyright © Carl Farmer