Orchestes testaceus (Müller, 1776)
Alnus glutinosa, Hongarije, Kimle © László Érsek: mine with cocoon
larva in opened 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
mine
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 midrib and the frayed leave missing a large part of its distal half remains unmistakable (lower picture).
hostplants
Betulaceae, oligophagous
Alnus glutinosa, incana, x pubescens, x spaethii.
phenology
Larvae in May-June (Scherf, 1964a); adults emerge in June (Rheinheimer & Hassler, 2010a).
BENELUX
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).
larva
pupa
synonyms
Rhynchaenus, Trecticus, testaceus; Rhynchaenus scutellaris (Fabricius, 1801).
notes
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)
It has long be assumed that O. testaceus and O. calceatus were one and the same species. This has definitely been refuted by Košťál & Caldara.
references
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), Košťál & Caldara (2013a), Kozlov, van Nieukerken, Zverev & Zvereva (2013a), le Monnier (2003a), Morris (1993a), Rheinheimer & Hassler (2010a), Robbins (1991a), Scherf (1964a), Seidel (1926a), Skala (1936a), Sønderup (1949a), Viramo (1962a, 1970a, 1975a), Vorst (2010a).