(Coleoptera, Diptera, Hymenoptera and Lepidoptera)

by Brian Pitkin, Willem Ellis, Colin Plant and Rob Edmunds

DRYAS. Mountain Avens. [Rosaceae]

One species of Dryas is recorded in Britain, Mountain Avens (D. octopetala).

Two miners are recorded on Dryas.

The tortricid Cnephasia conspersana is recorded as a seed / shoot-feeder on Dryas in Britain.

A key to the European miners recorded on Dryas is provided in Bladmineerders van Europa.

Key for the identification of the known mines of British
insects (Diptera and non-Diptera) recorded on Dryas

1a > Leaf-miner: The larva first makes a lower-surface epidermal corridor. Next the larva begins to feed on the sponge parenchyma, subsequently also the palissade parenchyhma; the initial corridor becomes obliterated. The final mine is full depth, occupies half of a leaf, at one side of the midrib, and is almost flat. The upperside turns orange brown. Finally the larva vacates its mine and spins a new leaf into a pod, that is eaten from the inside. If needed another leaf is treated the same way.

On Dryas octopetala in Britain and elsewhere. West Sutherland in Britain and Austria, French mainland, Germany, Italian mainland and Switzerland in continetal Europe.

1b > Leaf-miner: Egg on the leaf margin or the underside of the leaf. The mine is a corridor, narrow at first, for about 10 mm descending towards the base of the leaf, meticulously following the leaf margin. Then the corridor reverses its direction, and widens into a blotch that may occupy half of the leaf, to the midrib. Frass in the corridor as a broad central ribbon; broadly scattered in the blotch.

On Dryas octopetala in Britain and elsewhere. North Ebudes in Britain. Widespread in continental Europe.

Stigmella dryadella (O. Hofmann, 1868) [Lepidoptera: Nepticulidae]