ASPLENIUM. Spleenworts and Wall-rue. [Aspleniaceae]

Eight species of Asplenium are native to Britain - Black Spleenwort agg. (A. adiantum-nigrum), Sea Spleenwort (A. marinum), Lanceolate Spleenwort (A. obovatum), Irish Spleenwort (A. onopteris), Wall-rue (A. ruta-muraria), Forked Spleenwort (A. septentrionale), Maidenhair Spleenwort (A. trichomanes) and Green Spleenwort (A. viride). A ninth species Smooth rock-spleenwort (A. fontanum) is introduced.

Phyllitis scolopendrium is treated as Asplenium scolopendrium (Rustyback) by Stace (2010).

Only one Diptera miner, the agromyzid Chromatomyia scolopendri, is recorded on Asplenium in Britain, and this also occurs on Phyllitis and Polypodium.

Elsewhere the fern-feeding agromyzids Chromatomyia scolopendri and Phytoliriomyza hilarella and the fern-feeding anthomyiids Chirosia grossicauda and Chirosia histricina are recorded mining Asplenium.

Two non-Diptera mines, Psychoides verhuella and Psychoides filicivora are recorded on Asplenium in Britain (see below).

A key to the European miners, based on characteristics of the mines, immature stages and where relevant the larval cases, recorded on Asplenium is provided in Bladmineerders van Europa. This includes Chirosia grossicauda, Chirosia histricina, Chromatomyia scolopendri, Phytoliriomyza hilarella, Psychoides verhuella and Psychoides filicivora.

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

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: Larvae usually feed on the underside of a fern frond under an untidy mass of sporangia, but on occasion enter the leaf to make an extensive irregular blotch mine (British leafminers). Usually the larva lives free under the leaf, under an inrregular mass of spun soredia and frass. The larva feeds on the sori, and larva betrays its presence as a sorus on an unusual place. Sometimes also elongate full depth blotches are made (Bladmineerders van Europa).

Recorded on Asplenium, Phyllitis, Polystichum and Dryopteris, but not yet on Cetarach or Polypodium, in Britain and Asplenium, Ceterach, Phyllitis, Polystichum and Dryopteris elsewhere. Widespread in southern England and Wales. Initially occurred mainly near coasts, but it is increasingly recorded inland. Outside of Britain and Northern Ireland, only recorded in Madeira.

Psychoides filicivora (Meyrick, 1937) [Lepidoptera: Tineidae]

1b > Leaf-miner:Full-depth corridor or blotch, often positioned along the leaf margin. In the first part much, brown-black, fine-grained frass, later parts of the mine almost free from frass. After hibernation the larva lives free in an untidy case of silk, covered with remants of sori (Bladmineerders van Europa).

Recorded on Asplenium, Ceterach, Phyllitis and Polystichum, but not yet on Poypodium, in Britain and Asplenium, Ceterach, Phyllitis, Pteridium and Dryopteris elsewhere. Widespread in Britain and continental Europe.

Psychoides verhuella Bruand, 1853 [Lepidoptera: Tineidae]