Dialectica imperialella (Zeller, 1847)
fen slender
Symphytum officinale, Belgium, prov. Liège, Oreye: mine with young, colourless, larva © Jean-Yves Baugnée
Symphytum officinale, Nieuwendam; mine, upper side
same mine, lower side
same mine again, lighted from behind, with full grown larva
Symphytum officinale, Nieuwendam: detail detail of the start of the mine.
Pentaglottis sempervirens, Belgium, West Flanders, Wielsbeke © Steve Wullaert
underside of the leaf; exceptionally heavy infestation
Echium plantagineum, Belgium, prov Antwerp, Mol; © Carina Van Steenwinkel
mine
A number of eggs are deposited over a wide area of the underside of a leaf. The larvae make very wide epidermal galleries, that are hardly discernable, but for the tread thin line of frass that is glued to the floor of the mine. Gradually the larvae come together, and the mine becomes deeper, and finally becoming locally full depth. Only then the mine is apparent from above as some disconnected brownish spots. At the underside the mine is quite larger, membraneous. Pupation usually is outside the mine.
hostplants
Boraginaceae, oligophagous
Aegonychon purpurocaeruleum; Lithospermum officinale; Pulmonaria angustifolia, officinalis; Symphytum officinale.
Found in 2012 by Steve Wullaert on Pentaglottis sempervirens, by Carina Van Steenwinkel on Echium plantagineum.
phenology
Larvae in August – September (Emmet, Watkinson & Wilson, 1985a).
BENELUX
BE recorded (Phegea, 2009).
NE recorded (Kuchlein & de Vos, 1999a; Microlepidoptera.nl, 2009).
LUX recorded (Fauna Europaea, 2009).
distribution within Europe
From Denmark to the Pyrenees, Italy, and Romania, and from the UK to Russia and Ukraine (Fauna Europaea, 2009).
larva
pupa
Described by Patočka (2001b), Patočka & Turčáni (2005a).
predators
synonyms
Acrocercops, Gracillaria imperialella.
references
Barton (2018a), Beiger (1980a), Bengtsson & Johansson (2011a), Biesenbaum (2010a), Buszko (1987a, 1992b), Doets (1946a), Drăghia (1968a), Emmet, Watkinson & Wilson (1985a), Gomboc & Kirichenko (2022a), Huisman, Koster, van Nieukerken & Ulenberg (2001a, 2003a, 2004a, 2005a, 2006a), Kasy (1965a), Kuchlein & Donner (1993a), Klimesch (1950c), Kuchlein & Donner (1993a), Kuchlein & de Vos (1999a), Mifsud & Askew (2019a), van Nieukerken, Gielis, Huisman ao (1993a), Patočka (2001b), Patočka & Turčáni (2005a), De Prins (2010a), De Prins & Steeman (2013a), De Prins, Steeman & Sierens (2016a), Starý (1930a), Szőcs (1977a), Wieser & Huemer (1999a).