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

 

X CRATAEMESPILUS. [Rosaceae]


X Crataemespilus is a name applied to graft chimeras between the genera of Crataegus and Mespilus.

Four British miners are recorded on X Crataemespilus.

A key to the European miners recorded on Crataegus including Crataemespilus is provided in Bladmineerders van Europa and to Mespilus in Bladmineerders van Europa.



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


1a > Leaf miner: In a small Phyllonorycter-like mine initially, but with brown rather than green lower epidermis. Later in two or more successive cones formed by folding leaf-lobes downwards. The mine begins at a flat, iridescent egg shell. It starts as an epidermal corridor, widening into (and mostly over run by) a shallow lower surface blotch in the tip of a leaf segment. The lower epidermis is off-grey with small light brown spots at first, but soon turns brown. Silk is deposited within the mine, causing it to contract. This wrinkles the lower epidermis, but there are no clear folds formed. Soon the larva starts consuming the palissade parenchyma, and the upperside of the mine than turns brown as well. Frass in loose grains. After some time the larva leaves its mine and continues living free under a downfolded leaf segment, kept in place by some spinning. Here too the leaf tissue is consumed up to the palissade parenchyma, browning the leaf.

On Crataegus, Fragaria and Sorbus, but not yet on X Crataemespilus, in Britain and Amelanchier, Cotoneaster, Crataegus, X Crataemespilus, Fragaria, Mespilus and Sorbus elsewhere. Widespread in Britain, Ireland and continental Europe.

Parornix anglicella (Stainton, 1850) [Lepidoptera: Gracillariidae].

1b > Leaf miner: The mine is often in the lobe of the leaf. There are many creases in lower epidermis, which is strongly contracted, causing lobe or leaf-edge to fold over. Rather small, lower-surface, tentiform mine with a yellow-green epidermis that has a number of folds. Pupation within the mine. The pupa of the summer generation in a quite flimsy cocoon; in the autumn generation there is more, golden, silk. All frass in a clump in the distal angle of the mine.

On Crataegus, Cydonia and Pyrus, but not yet on X Crataemespilus, in Britain and Crataemespilus, Crataegus, Cydonia, Mespilus, Pyracantha, Pyrus and Sorbus elsewhere. Widespread in Britain, Ireland and continental Europe.

Phyllonorycter oxyacanthae (Frey, 1856) [Lepidoptera: Gracillariidae].

1c > Leaf miner: The reddish frass is linear, later in arcs, finally dispersed. Long corridor, that widens only little, and winds freely through the leaf, not influenced by the venation. In thick, sun-exposed leaves the mine may be much shorter, especially in Cotoneaster, Malus and Pyrus. Frass brown, in arcs..

On Cotoneaster, Crataegus, Malus, Pyrus and Sorbus, but not yet on X Crataemespilus, in Britain and Amelanchier, ? Chaenomeles, Cotoneaster, Crataegus, Crataemespilus, Cydonia, Malus, Mespilus, Prunus, Pyrus and Sorbus elsewhere. Widespread in Britain. Also recorded in the Republic of Ireland. Widespread in continental Europe.

Stigmella oxyacanthella (Stainton, 1854) [Lepidoptera: Nepticulidae].

1d > Leaf-miner: The larvae mine the leaves of hawthorn, creating a gallery which begins narrowly with black linear frass. The mine then widens, and the frass is laid in distinct arcs, finally becoming irregular and central near the end. Egg at the underside of the leaf, often close to a vein; occasionally on the petiole. The mine is a corridor. In its first part the frass lies in a central line, later is is clearly coiled. The corridor makes some sharp hairpin turns, while the loops remain so close together that usually a secondary blotch is the result. The mine can cross lateral veins. The larva is green.

On Crataegus, but not yet on X Crataemespilus, in Britain and Crataegus and X Crataemespilus elsewhere. Widespread in Britain, Ireland and continental Europe.

Stigmella crataegella (Klimesch, 1936) [Lepidoptera: Nepticulidae].



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