Agromyza megalopsis Hering, 1933

on Hordeum

Hordeum vulgarem Hungary, Mosonmagyaróvár, 20.v.2020 © László Érsek

larva in the mine

larva, ventral

mandibles

fresh puparium

hardened puparium

parasitation

mine

A small number of eggs is deposited in a transverse row, near the leaf margin, not far from the leaf base. From each egg a corridor starts running towards the leaf tip. Neighbouring corridors merge, finally one mine results with several larvae. After the first moult the direction of the mine reverses, wihle the mine widens considerably. About half of the puparia is formed in the mine (Geigenmüller, 1966a; Hering, 1962a), but these observations were made during a mass occurrence, therefore under circumstances that were not quite normal.

hostplants

Poaceae, narrowly oligophagous

Hordeum vulgare & subsp. distichon; Secale; Triticum.

Hordeum is the most important hostplant by far. According to Papp & Černý references to Triticum are even incorrect.

distribution within Europe

From Poland to Spain and from France to Crete (Černý & Merz, 2006a; Gil Ortiz, 2009a; Fauna Europaea, 2011).

larva

Described by Darvas & Papp (1985a); the mandible is said to have 2 large teeth, with 2 smaller teeth more proximal; front spiraculum with 9, posterior spiraculum with 9 papillae.

puparium

Rear spiracula (with 3 papillae) so close that they touch each other (Spencer, 1966a, 1973b).

synonyms

Altgough this species was described by Hering in 1933, he never mentioned it, not even in his major work of 1957, until in 1962. This can hardly mean otherwise than that in some of Hering’s descriptions of otherAgromyza‘s megalopsis must have been substituted.

notes

Not known from the Benelux, but recorded from Germany (von Tschirnhaus, 1999a), and both there and around Paris a pest of barley and rye (Dempewolf, 2004a; Geigenmüller, 1966a; d’Aguilar, Chambon & Touber, 1976a).

Griffiths (1963a) supposes that megalopsis belongs to the A. ambigua group of species (Darvas & Papp, 1985a do not dwell on the species’ taxonomy), and the place of the species in the identification key is based on that assumption.

references

d’Aguilar, Chambon & Touber (1976a), Černý (2001a), Černý, Barták & Roháček (2004a), Černý & Merz (2006a), Černý & Vála (1999a, 2006a), Černý, Vála & Barták (2001a), Ci̇velek, Çikman & Dursun (2008a), Darvas & Papp (1985a), Darvas, Skuhravá & Andersen (2000a), Dempewolf (2004a), Gallo (1996a), Gil Ortiz (2009a), Gil-Ortiz, Martinez & Jiménez-Peydró (2010a), Geigenmüller (1966a), Hering (1933c, 1962a), Griffiths (1963a), Papp & Černý (2015a), Spencer (1966a, 1973b), von Tschirnhaus (1999a).