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


Dialectica scalariella (Zeller, 1850)
[Lepidoptera: Gracillariidae]

Gracillaria scalariella Zeller, 1850
Dialectica scalariella
(Zeller, 1850)

Leaf-miner: Mine upper-surface or, more often, lower-surface. At first a long, narrow, winding epidermal gallery with central, more or less deliquescent, reddish brown frass. The gallery abruptly widens into an elongate blotch that is epidermal at first but soon deeper; the blotch is brown with strikingly white margins. Epidermis finely wrinkled. Lower surface mines strongly contract the leaf (and often there is a mine at either side of the midrib). 2-3 Larvae in a blotch, each with its own initial corridor. Frass in large black grains in a central depot; moreover in the form of very thin threads stuck in a reticulate pattern in the epidermis (Bladmineerders van Europa).

Larva: Details unknown. 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).

Pupa: Hering (1957a) states that the pupa lies naked in the mine but pictures on Lepiforum show normal cocoons, with a thin silken wall, not covered by frass. At emergence the pupa works itself for a large part out of the mine (Bladmineerders van Europa).

Adult: The adult is not illustrated in UKMoths (check for update). The species is included in

Hosts in Great Britain and Ireland: Currently unknown.

Hosts elsewhere:

Anchusa strigosa     Bladmineerders van Europa
Cynoglossum creticum     Bladmineerders van Europa
Echium aculeatum     Bladmineerders van Europa
Echium candicans     Bladmineerders van Europa
Echium gaditanum     Bladmineerders van Europa
Echium giganteum     Bladmineerders van Europa
Echium nervosum     Bladmineerders van Europa
Echium plantagineum     Bladmineerders van Europa
Echium vulgare Viper's-bugloss British Wild Flowers by John Somerville et al. Bladmineerders van Europa
Myosotis latifolia     Bladmineerders van Europa
Lithospermum officinalis     Belgian Lepidoptera
Lithospermum officinalis     Belgian Lepidoptera
Pulmonaria officinale     Belgian Lepidoptera
Symphytum officinale Common Comfrey British Wild Flowers by John Somerville et al. Belgian Lepidoptera
Symphytum officinale Common Comfrey British Wild Flowers by John Somerville et al. Bladmineerders van Europa

Time of year - larvae: Currently unknown.

Time of year - adults: Currently unknown.

Distribution in Great Britain and Ireland: First recorded in the UK in Kent (2004), when a moth was trapped (British leafminers).

Distribution elsewhere: Widespread in continental Europe including Azores, Canary Islands, Corsica, Crete, Croatia, French mainland, Germany, Gibralter, Greek mainland, Italian mainland, Madeira, Malta, Portuguese mainland, Sardinia, Sicily, Spanish mainland, and Switzerland (Fauna Europaea).

Introduced in Australia for the biological control of the serious weed Echium plantagineum (Patterson's curse), originating from southern Europe (Kumata & Horak, 1997a; Walsh, Woods & Dodd, 1993a; Wapshere & Kirk, 1977a), see Bladmineerders van Europa.

NBN Atlas links to known host species:

Echium vulgare, Symphytum officinale

British and Irish Parasitoids in Britain and elsewhere: Currently unknown.

External links: Search the internet:

Belgian Lepidoptera
Biodiversity Heritage Library
Bladmineerders van Europa
British leafminers
Encyclopedia of Life
Fauna Europaea
NBN Atlas
NHM UK Checklist

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Last updated 23-May-2019  Brian Pitkin Top of page