Orchestes testaceus (Müller, 1776)
Alnus glutinosa, Hongarije, Kimle © László Érsek: mine with cocoon
larva in opned cocoon
Alnus x spaethii, Aalten
Alnus glutinosa, Belgium, prov. Antwerp, Balen, Scheps © Carina Van Steenwinkel
same leaf, underside, with oviposition scar
another mine, lighted from behind
larva, ventral view
Alnus incana, Belgium, prov. Namur, Lives; © Jean-Yves Baugnée
Alnus glutinosa, Orvelte
Oviposition in the underside of the midrib or a thick lateral vein; later a large scar is visible there. Initially the larva tunnels in the midrib or vein, that inflates and disfigures somewhat as a result. Then the larva starts a corridor in the leaf blade, quite narrow at first, but strongly widening as the larva approaches the leaf margin or leaf tip. The mine is reddish brown in colour. The mature larva makes itself a dark brown globular cocoon in the mine and pupates there.
Because the mine is made at a time that the leaf still is unfolding, the leaf becomes permanently rumpled. In the course of the summer the mine erodes away, but the combination of the oviposition scar, the swollen mibrib and the frayed leave missing a large part of its distal half remains unmistakable (lower picture).
Larvae in May-June (Scherf, 1964a); adults emerge in June (Reinheimer & Hassler, 2010a).
BE recorded (Curculionidae.be, 2010).
NE recorded (Heijerman, 1993a).
LUX not recorded (Fauna Europaea, 2007).
distribution within Europe
Almost all of Europe, except Ireland, the Iberian Peninsula and the Balkan Peninsula (Fauna Europaea, 2007).
Rhynchaenus, Trecticus, testaceus; Rhynchaenus scutellaris (Fabricius, 1801); Orchestes calceatus (Germar, 1821).
According to Hering (1957a) the species is very common throughout Europe, and this is confirmed for the Netherlands by van Frankenhuyzen a.o. (1982a); in my experience during the last decade is rather uncommon in the Netherlands. Also in the UK the species is fairly scarce (Morris, 1993a).
Although the Fauna Europea (2011) considers O. calceatus and testaceus synonyms, there probably exist biological differences between both taxa: testaceus is said to live exclusively on Alnus, calceatus only on Betula (Morris, 1993a; Reinheimer & Hassler, 2010a; Viramo, 1970a). O. calceatus then can be divided in a western European subspecies O. c. semirufus and the typical subscies calceatus in northern and eastern Europe (Viramo, 1970a).
Ahr (1966a), Beiger (1979a), Buhr (1933a, 1964a), Drăghia (1968a), van Frankenhuyzen & Houtman (1972a), van Frankenhuyzen a.o. (1982a), von Frauenfeld (1864a), Hartig (1939a), Heijerman (1993a), Hering (1927b, 1930a, 1957a), Huber (1969a), Kleine (1924/25a), Kozlov, van Nieukerken, Zverev & Zvereva (2013a), le Monnier (2003a), Morris (1993a), Reinheimer & Hassler (2010a), Robbins (1991a), Scherf (1964a), Seidel (1926a), Skala (1936a), Sønderup (1949a), Viramo (1962a, 1970a, 1975a), Vorst (2010a).