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

 

LIGULARIA. Leopardplants. [Asteraceae]


Four species of Ligularia are recorded in Britain. They are all introduced.

Only one British miner is recorded on Ligularia.

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



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


1 > Leaf-miner: The mine begins as a long, quite narrow corridor, usually not far from the tip of a leaf segment. Usually this corridor follows the leaf margin for some distance, but it may also run freely through the blade and may then be stongly contorted. In the end the corridor is directed towards the midrib, where an elongated blotch is formed, overlying the midrib and some of the larger lateral veins. Frass in a nearly continuous line in the initial corridor, in scattered lumps in the later part of the mine. Primary and secondary feeding lines very conspicuous when seen in transparancy. Pupation outside the mine.

The mine starts as a very narrow corridor, usually close to the tip of a leaf segment and following the leaf margin. The later section of the corridor approaches the main vein, where an elongated blotch is made with long broad finger like extensions that lay over the secondary veins. In the initial corridor the frass forms an almost continuous line, in the blotch it is distributed in large scattered lumps. In fresh mines the secondary feeding lines are clearly visible.

On numerous genera of Asteraceae, but not yet on Ligularia, in Britain, Throughout the British Isles, more common in the south than the north. Also continental Europe.

Trypeta zoe Meigen, 1826 [Diptera: Tephritidae].



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ng> (Hübner, 1796) [Lepidoptera: Gracillariidae].

1b > Leaf-miner: Larvae usually gregarious. Early mine an epidermal gallery leading to a contorted blotch with black frass. Subsequently two successive cones formed by folding the tip of a leaf downwards (British leafminers, as Caloptilia syringella). Often, many leaves on a single bush turn brown and curl up with the mines. The species can be a pest in gardens. The mine begins at a row of eggs along the midrib. The emerging larvae form relatively broad, inconspicuous, lower-surface corridor. Subsequently a large, grey brown or greenish brown, very opaque upper-surface blotch is made, occupied by ten or more larvae. The mine makes the leaf somewhat bumpy, but the leaf does not fold around the mine, like in Caloptilia cuculipennella. After some time the larvae leave the mine and continue feeding, still comunnally, in a downwards rolled leaf.

Gracillaria syringella larva
Gracillaria syringella larva
Image: © Willem Ellis (Bladmineerders van Europa)

On Symphoricarpos, Fraxinus, Jasminum, Ligustrum, Phillyrea and Syringa in Britain and Chionanthus, Forestiera, Forsythia, Fraxinus, Jasminum, Ligustrum, Phillyrea and Syringa elsewhere. Widespread in Britain, Ireland and continental Europe.

Gracillaria syringella (Fabricius, 1794) [Lepidoptera: Gracillariidae].

1c > Leaf-miner: It is the third generation, appearing in the autumn and overwintering, which mines leaves. The larvae spin the leaves, forming a protective cover. The spring (first) generation attack the developing flowers and the second generation live inside the olive kernels. Initially the larva makes an upper-surface, short, narrow corridor. Later, in early spring, it may abandon this mine and make elsewhere on the leaf an irregular full depth blotch, or it may continue the corridor into a blotch. Most frass is ejected through a hole in the mine; part of it is captured in spinning at the leaf underside. In the end the larva lives free under the leaf, causing window feeding.

On Olea, Jasminum, Ligustrum and Phillyrea in Britain and Olea and Phillyrea elsewhere. First discovered in the Surrey in 2009. Widespread in continental Europe.

Prays oleae (Bernard, 1788) [Lepidoptera: Yponomeutidae].



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