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

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Elachista trapeziella Stainton, 1849
[Lepidoptera: Elachistidae]

Scarce Dwarf

Elachista trapeziella Stainton, 1849
Biselachista trapeziella (Stainton, 1849).

Leaf-miner: The mine in Luzula pilosa is rarely at the leaf-tip, being usually about halfway down the leaf blade and well clear of the winter/pring dieback. The autumn mine typically consists of a long stright slended gallery folloowing one of the veims. The mine is no wider than the larva and the frass is scattered towards or away from the leaf-tip. In spring the mine is contined as a broad elongated gallery with frass irregularly placed. Pupation occurs on the upper surface of a leaf and is anchored by a silk girdle (Bland and Knill-Jones, 1988).

From autumn till early spring the larva makes a quite narrow corridor with a total length of 12-16 cm, essentually running parallel to the leaf venation; the corridor may change direction 2-3 times. Generally the corridor lies about halfway the length of the leaf. In March-April this gallery abruptly gives way to an elongate blotch, that generally obliterates the original gallery. The larva may leave its mine and restart elsewhere by making a lower-surface opening in a new leaf, not far from the leaf-tip. Pupation external (Bladmineerders van Europa).

Larva: The larvae of moths have a head capsule and chewing mouthparts with opposable mandibles (see video of a gracillarid larva feeding), six thoracic legs and abdominal legs (see examples).

The larva has a black head and prothoracic plates with a pink body and narrow creamy nid-dorsal line and a more diffuse creamy line along the spiracles. The intensity of the pink varies considerably (Bland and Knill-Jones, 1988).

Body more or less intensely pink, with three cream-coloured length lines; head and prothoracic plate black (Bladmineerders van Europa).

Pupa: The pupae of moths have visible head appendages, wings and legs which lie in sheaths (see examples).

See Patocka (1999a), Patocka and Turcáni (2005a) (Bladmineerders van Europa).

Adult: The adult is illustrated in UKMoths. The genitalia are not illustrated by the Lepidoptera Dissection Group (check for update).

Hosts in Great Britain & Ireland:

Luzula pilosa Hairy Wood-rush British Wild Flowers by John Somerville et al. Pitkin & Plant (as Biselachista)
Luzula sylvatica Great Wood-rush British Wild Flowers by John Somerville et al. Pitkin & Plant (as Biselachista)

Hosts elsewhere:

Luzula luzuloides White Wood-rush   Bladmineerders van Europa
Luzula pilosa Hairy Wood-rush British Wild Flowers by John Somerville et al. Bladmineerders van Europa
Luzula sylvatica Great Wood-rush British Wild Flowers by John Somerville et al. Bladmineerders van Europa

Time of year - larvae: Autumn to April-June of the following year (Bladmineerders van Europa).

Time of year - adults: Currently unknown.

Distribution in Great Britain & Ireland: Britain including East Norfolk (VC27), East Ross (VC106), Forfar, Kincardineshire (VC91), North Devon and South Wiltshire ( NBN Gateway, as Biselachista trapeziella).

Also recorded in the Republic of Ireland (Karsholt and van Nieukerken in Fauna Europaea). See also Ireland's NBDC interactive map.

NBN Grid Map:

NBN Grid Map

Elachista trapeziella, as Biselachista trapeziella
NBN Grid Map : NBN Terms and Conditions

Maps are only displayed if the NBN server is active. N.B. Only publicly available records, if any, are shown by default

Distribution elsewhere: Widespread in continental Europe including Austria, Belgium, Czech Republic, Danish mainland, Finland, French mainland, Germany, Italian mainland, Latvia, Norwegian mainland, Poland, Slovakia, Sweden and Switzerland (Karsholt and van Nieukerken in Fauna Europaea).

NBN Interactive Grid Maps of known host species:

Luzula luzuloides, Luzula pilosa, Luzula sylvatica

British and Irish Parasitoids in Britain and elsewhere:

Centistes fuscipes (Nees, 1834) Braconidae: Euphorinae
Pholetesor viminetorum (Wesmael, 1837) Braconidae: Microgastrinae

External links: Search the internet:

Belgian Lepidoptera
Biodiversity Heritage Library
Bladmineerders van Europa
British leafminers
Encyclopedia of Life
Fauna Europaea
NBN Gateway, as Biselachista trapeziella
NHM UK Checklist, as Biselachista trapeziella

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Last updated 21-Jul-2016  Brian Pitkin Top of page