Orchestes testaceus (Müller, 1776)

Orchestes testaceus: mine with cocoon

Alnus glutinosa, Hongarije, Kimle © László Érsek: mine with cocoon

Orchestes testaceus: larva in cocoon

larva in opned cocoon

Orchestes testaceus: mine

Alnus x spaethii, Aalten

Orchestes testaceus: mine on Alnus glutinosa

Alnus glutinosa, Belgium, prov. Antwerp, Balen, Scheps © Carina Van Steenwinkel

Orchestes testaceus: mine on Alnus glutinosa

same leaf, underside, with oviposition scar

Orchestes testaceus: mine on Alnus glutinosa

another mine, lighted from behind

Orchestes testaceus: larva

larva, ventral view

Orchestes testaceus mine

Alnus incana, Belgium, prov. Namur, Lives; © Jean-Yves Baugnée

9963

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 mibrib 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; Betula nana, pendula, pubescens.

phenology

Larvae in May-June (Scherf, 1964a); adults emerge in June (Reinheimer & 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); Orchestes calceatus (Germar, 1821).

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).

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).

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), 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).

23/01/2017

mod 25.vii.2017