FRANGULA. Alder Buckthorn. [Rhamnaceae]

Alder Buckthorn (F. alnus) is the only species of Frangula recorded in Britain.

No Diptera miners are recorded on Frangula in Britain.

Two non-Diptera miners are recorded on Frangula in Britain (see below).

Elsewhere two additonal British non-Diptera miners are recorded on Frangula (see below).

A key to the European miners, based on characteristics of the mines, immature stages and where relevant the larval cases, recorded on Rhamnus including Frangula is provided in Bladmineerders van Europa. This includes Bucculatrix alaternella, Bucculatrix frangutella, Bucculatrix rhamniella, Calybites quadrisignella, Coleophora ahenella, Coleophora violacea, Hedma rhamnifoliae, Thiodia glandulosana, Trachys minutus, Stigmella alaternella, Stigmella catharticella, Stigmella crenulatae, Stigmella pyrellicola, Stigmella rhamnella and Stigmella rhamnophila but not Lyonetia clerkella or Recurvaria nanella.

Key for the identification of British non-Diptera mines recorded on
Frangula

Note: The larvae of mining Coleoptera, Hymenoptera and Lepidoptera may live in a corridor mine, a corridor-blotch mine, a blotch mine, a case, a rolled or folded leaf, a tentiform mine or sandwiched between two more or less circular leaf sections in later instars. Larva may pupate in a silk cocoon. The larva may have at least six legs (although they may be reduced or absent), a head capsule and chewing mouthparts with opposable mandibles (see video of a gracillarid larva feeding). Larvae of Hymenoptera and Lepidoptera usually also have abdominal legs (see examples). Frass, if present, never in two rows. Unless feeding externally from within a case the larva usually vacates the mine by chewing an exit hole. Pupa with visible head appendages, wings and legs which lie in sheaths (see examples).

1a > Leaf-miner and case bearer: The larva lives outside the mine, protected by a case, and feeds on the underlying plant tisses via a hole cut in the epidermis. Mine does not contain frass (Coleophora species)

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1b > Leaf-miner, but not a case-bearer: The larva lives mainly inside the mine. Mine usually contains frass. In later instars the larva may live sandwiched between two more or less circular sections cut from the leaf e.g. Incurvaria species.

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2 > Leaf-miner and case-bearer: Lobe case. The full grown case is about 7 mm long. The mouth angle is 0°, causing the case to lie flat on the leaf. The case is gradually enlarged by the addition of rings that are cut out of the epidermis. The rings become gradually larger, and stick irregularly out of the contour of the case. The rings are cut out of the lower epidermis of the mine. This implies that mines may have both normal, small openings, and large ones. Compare for instance C. violacea, that cuts rings out of the upper epidermis (Bladmineerders van Europa). The larva feeds briefly initially and again after over wintering. It then aestivates until Autumn. It makes one case which it enlarges by adding pieces of excised lower epidermis (British leafminers).

Recorded on Cornus, Frangula, Lonicera, Rhamnus, Symphoricarpos and Viburnum in Britain and Cornus, Frangula, Lonicera, Rhamnus, Swida, Symphoricarpos and Viburnum elsewhere. Southern England. Widespread in continental Europe.

Coleophora ahenella Heinemann, 1877 [Lepidoptera: Coleophoridae].

3a > Leaf-miner: The highly distinctive, violet or purplish spiral mines of this species are often the key to its discovery. They can be found on leaves, often several to a leaf. After the initial leaf-mining phase, the larva feeds externally on the underside of the leaves, creating small feeding windows, before pupating in a ribbed cocoon typical of the Bucculatriginae (UKMoths). A narrow corridor, densely wound, amost entirely filled with purplish brown frass. The last 1 to 2 cm of the corridor are free from the spiral, and almost straight. At this point the mine is left and the larvae continue to live free on the leaf, causing window feeding. The empty larval chamber, obviously free from frass, is conspicuousy slender. The egg, in the very centre of the spiral, is at the leaf lower side, as is the exit from the mine (Bladmineerders van Europa).

Recorded on Frangula and Rhamnus in Britain and elsewhere. Widespead in England and continental Europe. Also recorded in the Republic of Ireland.

 

Bucculatrix frangutella (Goeze, 1783) [Lepidoptera: Bucculatricidae].

3b > Leaf-miner: The gallery is contorted in a series of S turns. The frass is initailly cloudy but then darker green being either dispersed or coiled (as shown). A little area of uneaten leaf is between each traverse. Finally the frass turns black and is deposited in a central line. The larva is greenish yellow, head pale brown (British leafminers). Full depth corridor, beginning at an under-surface egg shell. The corridor makes several sharp turns, causing the loops to (mostly) almost touch each other. In the last section the corridor is appreciably wider. Frass olive green when fresh, brown later, coiled for most of the length of the corridor. Pupation outside the mine (Bladmineerders van Europa).

Recorded on Rhamnus, but not yet on Frangula, in Britain and Rhamnus and ? Frangula elsewhere. Widespead in England and continental Europe. Also recorded in the Republic of Ireland.

Stigmella catharticella (Stainton, 1853) [Lepidoptera: Nepticulidae].

3c > Leaf-miner: Full depth blotch, invariably beginning at the leaf tip or the tip of a leaf lobe or tooth. Oviposition site covered by a black, shining drop of hardened secretion. Frass generally in long threads, but sometimes in elongated granules. Larva without abdominal legs. Pupation in the mine, not in a cocoon (Bladmineerders van Europa).

Recorded on Corylus avellana, but not yet on Frangula, in Britain. Recorded on several genera and species in several plant families including Frangula elsewhere. Widespread in Britain and continental Europe.