Caloptilia populetorum (Zeller, 1839)

clouded slender

Betula pendula x pubescens, Doorn, Moersbergen, 10.ix.2020 © Ben van As

Betula pendula, Amerongse Berg, 24.ix.2020 © Ben van As

Betula pendula, forestry Gieten, 3.x.2010 © Kees Boele: early leaf roll

final leaf roll

Betula pendula, Belgium, Liège, Terril Batterie Nouveau, 18.x.2010 © Jean-Yves Baugnée: cocoon (identification uncertain, betulicola is possible as well)

mine

At first the mine is epidermal and rather large, sometimes even occupying the entire length of the leaf. At a later stage the larva begins to consume the tissue below the epidermis, and the mine becomes a tentiform one; the leaf is strongly contracted by then. The epidermis is brown. The mine may be lower-surface or upper-surface. After the mine has been vacated the larva moves twice. At first it lives in a rolled, sometimes just folded, leaf margin, next in a leaf that has been rolled lengthwise. Pupation in a cocoon at the underside of a leaf.

host plants

Betulaceae, monophagous

Betula pendula, pubescens.

Clear preference for B. pendula, contrary to C. betulicola, which is indifferent (Buszko, 1992c).

phenology

Larvae in July – August, pupae in end-July – September (Emmet ao, 1985a).

BENELUX

BE recorded (Steeman & De Prins, 2005a).

NE recorded (Kuchlein & de Vos, 1999a; Microlepidoptera.nl, 2009).

LUX recorded (Fauna Europaea, 2009).

distribution within Europe

Europe, except Italy, the Balkan Peninsula and the Mediterranean Islands (Fauna Europaea, 2009).

larva

Whitish, head light brown; pronotum without black markings (Brown, 1947a).

pupa

Described by Patočka & Zach (1995a) and Patočka & Turčáni (2005). Cocoon whitish, under a downfolded leaf margin, of of the leaf roll itself.

Dorsal image of head and pronotum of the pupa of C. populetorum (at left) and C. betulicola right). The pronotum of populetorum bears a pair of elongated ridges, while that in betulicola shows a pair of shallow depressions (from Patočka & Zachs).

synonyms

Gracillaria populetorum.

notes

It has long been assumed that the leaf rolls of C. betulicola would run perpendicular to the midrib, those of C. populetorum parallel with it. However, recently pictures by Ben van As (see above) show shoots bearing several leaf rolls where both pattern co-occurred. Apparently the rolls of both species are indistinguishable.
The unfortunate species name has caused quite some confusion. The species is included in a key to the Poplar miners by Hering (1927a) and accused of damage to Aspen and Willow by Delplanque (1998a).

references

Bengtsson & Johansson (2011a), Biesenbaum (2010a), SCS Brown (1947a), Buhr (1935a, 1936a, 1964a), Burmann (1943a), Buszko (1992b,c), Buszko & Beshkov (2004a), Corley, Marabuto, Maravalhas ao (2011a), Delplanque (1998a), Deutschmann (2008a), Emmet, Watkinson & Wilson (1985a), Hering (1923a, 1957a), Huisman & Koster (1994a), Huisman, Koster, van Nieukerken & Ulenberg (2005a), Jaworski (2009a), Kuchlein & Donner (1993a), Kuchlein & de Vos (1999a), Kuchlein ao (1988a), Leutsch (2011a), Opheim (1977a), Patočka & Turčáni (2005a), Patočka & Zach (1995a), De Prins (2010a), Robbins (1991a), Schütze (1931a), Steeman & De Prins (2005a), Szőcs (1977a), Thomann (1956a).