The leaf and stem mines of British flies and other insects
 

(Coleoptera, Diptera, Hymenoptera and Lepidoptera)

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

 

THALICTRUM. Meadow Rues. [Ranunculaceae]


Eight species of Thalictrum are recorded in Britain. These include the native Alpine Meadow-rue (T. alpinum), Common Meadow-rue (T. flavum) and Lesser Meadow-rue (T. minus).

Three British miners are recorded on Thalictrum in Britain.

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



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


1a > Stem-miner: Larva forming an external stem mine, with widely spaced grains of black frass. Pupation takes place at the end of the mine. Puparium black

On Aquilegia and Thalictrum in Britain and elsewhere. Only from Hunts and Cambridge in Britain. Also in Germany, Sweden and Estonia.

Ophiomyia aquilegiana Lundquist, 1947 [Diptera: Agromyzidae].

1b > Leaf-miner: Larva forming short, irregular white linear mine, with frass in conspicuous black strips. Pupation external, normally adhering to the leaf near the end of the mine until dislodged by rain or wind (Spencer, 1972b: 83 (fig. 269B; Spencer, 1976: 381 (figs 663B), 450).

A pale green, upper-surface, fairly broad, waving corridor; relatively short, up to 7 cm. Frass at first in grains, later in short thread fragments or pearl strings, at either side of the corridor. Often several mines in a leaf. Pupation outside the mine, exit slit in lower epidermis.

A relatively broad, short upper surface gallery. Frass in conspicuous black stripes .

On Aquilegia and Thalictrum in Britain and elsewhere. Common and widespread throughout the Britain, particularly in gardens. Also recorded in the Republic of Ireland. Widespread in much of Europe. Also recorded in the western U.S.A., the Himalayas and northern India.

Phytomyza minuscula Goureau, 1851 [Diptera: Agromyzidae].

1c > Leaf-miner: Larva forming a large primary blotch, sometimes several larvae feeding together with frass scattered irregularly throughout the mine; leaves often being largely destroyed and the plants suffering considerable damage (Spencer, 1976: 380, 381 (fig. 663A)).

Striking, large, somewhat inflated, upper-surface, often purple-brown blotch without a preceding corridor. The mine is unusual because locally also the spongy mesophyl is eaten away, making the mine locally full depth and giving it a mottled appearance (right picture below). The mine begins in the centre of the leaf, or the base of a leaf segment (Griffiths, 1956b). The very first part of the mine differs in colour and structure; probably it is made by the larvae before its first ecdysis. Frass in very fine grains scattered over the floor of the mine. Pupation outside the mine. Exit slit in upper epidermis (Pakalniskis, 2004a).

A large blotch is formed, sometimes by several larvae, on the upper surface of the leaf. Frass is found scattered throughout the mine .

On Aquilegia and Thalictrum in Britain and elsewhere. Common in southern Britain particularly in gardens. Also recorded in the Republic of Ireland, Europe. Range extending eastwards to the Kirghiz and Kazakh Republics of the [former] U.S.S.R.

Phytomyza aquilegiae Hardy, 1849 [Diptera: Agromyzidae].



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