|
CONVOLVULUS. Bindweeds and Convolvuluses. [Convulvulaceae] |
|
Field Bindweed (C. arvensis) is the only native species of Convolvulus recorded in Britain. Introduced species include Austraian Bindweed (C. erubicens), Ground Blue-convolvulus (C. sabatius), Mallowed-leaved Bindweed (C. althaeoides), Small Blue-convolvulus (C. siculus) and Tricolor Convolvulus (C. tricolor). Only one Diptera miner, Pegomya setaria, is recorded on Convolvulus in Britain. Elsewhere the polyphagous agromyzids Chromatomyia horticola and Liriomyza strigata are recorded mining Convolvulus. The agromyzid Melanagromyza albocilia is recorded boring the stems of Convolvulus elsewhere. One non-Diptera leaf-miner is recorded on Convolvulus in Britain (see below). Elsewhere one additional British non-Diptera miner is recorded on Convolvulus (see below). A key to the European miners, based on characteristics of the mines, immature stages and where relevant the larval cases, recorded on Convolvulus including Calystegia is provided in Bladmineerders van Europa. This includes Chromatomyia horticola, Apterona helicinella, Bedellia ehikella, Bedellia silvicolella, Bedellia somnulentella, Bucculatrix cantabricella, Cnephasia incertana, Dichomeris lamprostoma, Hodgesiella rhodorrhisella, Hodgesiella rebeli, Stigmella freyella, Titanio normalis and Trachys puncticollis but not Liriomyza strigata. |
|
Note: Diptera larvae may live in a corridor mine, a corridor-blotch mine, or a blotch mine, but never in a case, a rolled or folded leaf, a tentiform mine or sandwiched between two more or less circular leaf sections in later instars. Pupation never in a cocoon. All mining Diptera larvae are leg-less maggots without a head capsule (see examples). They never have thoracic or abdominal legs. They do not have chewing mouthparts, although they do have a characteristic cephalo-pharyngeal skeleton (see examples), usually visible internally through the body wall. The larvae lie on their sides within the mine and use their pick-like mouthparts to feed on plant tissue. In some corridor miners frass may lie in two rows on alternate sides of the mine. In order to vacate the mine the fully grown larva cuts an exit slit, which is usually semi-circular (see Liriomyza huidobrensis video). The pupa is formed within the hardened last larval skin or puparium and as a result sheaths enclosing head appendages, wings and legs are not visible externally (see examples). 1 > Leaf miner: Blotch mine. Broad corridor, widening into a large transparant blotch with 1 or several, proportionally very large larvae that quickly completely mine out a leaf, then move to another leaf. At the start of the first mine at the leaf underside 1 or more oval egg shells. Pupation outside the mine
Pegomya setaria (Meigen). |
|
Key for the identification of the mines of British
|
|
|
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: At first it makes a narrow gallery lined with frass, but subsequently it makes a series of large translucent yellowish brown blotch mines from which all frass is ejected. It also constructs under the leaf an 'aerial' network of silk threads in which it moves around and rests clear of the leaf surface when not feeding (UKMoths). The mine begins at an egg shell that almost invariably is placed on (not next to) the midrib. The egg is oval, not globular, like in the Nepticulidae. Here a narrow tortuous corridor of some 30 mm begins, with a central frass line, reminding of a Stigmella mine, that often cuts off part of the leaf, causing it to die. Then the larva leaves this mine and begins to make a series of full depth full depth mines (not necessarily on the same leaf). The larva is larger than the mine, and protrudes from it with the rear part of its body. The openings to all these mines are in the lower epidermis. Under the leaf an irregular spinning develops, in which frass grains are trapped. Pupation outside the leaf (Bladmineerders van Europa). The pupa is attached to a leaf without a cocoon. It has a dorsal keel and a pronounced facial beak (UKMoths).
Bedellia somnulentella (Zeller, 1847) [Lepidoptera: Bedellidae]
|
|
|
1b > Leaf-miner: In the first instar the larva mines the leaves, forming short, irregular, blotch-like mines, but in later instars it lives externally, feeding in spun leaves and often twisting those of tender shoots. Larval head light-brown or yellowish brown, edged with black postero-laterally, ocellar area blackish; prothoracic plate black edged with whitish anteriorly; abdomen dull dark green; pinacula distinct, black, sometimes brownish but with black bases to setae; anal plate large, black (Bradley et al., 1973). Small, full depth mine without a definite shape; little frass. Some silk is deposited in the mine. The larva soon leaves the mine and continues feeding among spun leaves (Bladmineerders van Europa).
Cnephasia incertana (Treitschke, 1835) [Lepidoptera: Tortricidae] |
| Last updated 04-Feb-2012 Brian Pitkin |  |
|