Gonioctena fornicata

Gonioctena fornicata

Gonioctena ( Spartomena ) fornicata, formerly Phytodecta fornicata, is a beetle of the family of leaf beetles and the subfamily Chrysomelinae. The genus name " Gonioctena " ( AltGr. Γωνία, Gonia "corner" and κτενός ktēīs, ktenós "comb" ) refers to the comb-like teeth arranged at the trailing edge of the rail ( Fig. 5, arrow B). The species name " fornicatus " (Latin ) means " curved " and refers to the pronotum. The name of the subgenus Spartomena alludes to the fact that the animal to Pfriemenginster ( altgr.: σπάρτος spártos " Pfriemenginster " ) can be found. The species is known as Luzerneschädling in Eastern Europe, Central Europe is rather rare.

Characteristics of the beetle

The beetle is slightly elongated and flatter than a ladybug. It reaches a length of five to seven millimeters. The drawing is highly variable. The almost black shapes only individual points or parts of the edge are red, the other extreme of the whole beetle to four dark spots on the elytra is red or reddish yellow. In the intermediate forms may on the pronotum, two spots or patches be on the wing covers together four, five, six or seven points. In addition, the points can coalesce into black areas.

The head is pulled up to his eyes in the pronotum. The eleven-membered sensors are thicker outwards. They are removed from each other, is hinged to the end on the root of the upper jaw ( Figure 2). The upper jaw are not hollowed out laterally ( to insert the pine key end member ).

The pronotum is strongly arched (name fornicatus ), whereas it is flat in many other species of the genus and particularly in the similar subscribed kind Gonioctena viminalis. In addition, the pronotum is dotted fine and dense; on the sides of the puncturing little more ( Figure 3). Behind the center of the reddish yellow pronotum are typically a pair of black round spots.

The coarse points of the elytra form nine distinct rows; the seventh row of dots is not resolved behind the center by next Asked points (Fig. 1), at most slightly irregular. The margins of the elytra are not ciliate at the tip. The Epipleuren run out to the rear and are inwardly bent back (less curved). Typically located on the elytra together five or seven radioed in which a point on the wing covers seam sits roughly in the middle, the remaining points are symmetrically distributed on the elytra. The scutellum is black.

All rails are recessed on top of the tarsi toward channel-like; in this depression the tarsi can be folded upwards. The outer edge of this groove is drawn in a tooth that lies at the center and rear rails on the end near the tarsi ( (Fig. 4), at the front rails of the tooth is removed from the inwardness of the tarsi and weaker formed (Fig. 5, arrow A). the reddish tarsi are all four members, but with the leaf beetles, a thickening on the jaw member as a rudimentary further Tarsenglied ( to be interpreted with the number 4). the third Tarsenglied is oberseits emarginate, but not clearly bilobed. the claws are at the base, each with a tooth provided (Fig. 5, arrow C).

Biology

Old information on rowan and gorse as a host plant are seen critical today, the species is classified as a pest on alfalfa and clover. The larvae feed mainly on leaves and young shoots, the beetles probably older drives.

The beetle has a life cycle of one year. It hibernates as imago at a depth of five to twenty-five centimeters. In spring, the beetles appear again and can then until the second half of June in Luzernekulturen (Medicago sativa) are harmful. After mating, the females lay between 200 and 1000 eggs in small portions, usually on the lower leaves off. The larvae go through four stages and are harmful by foliar feeding, especially in the last two stages. After three to four weeks, the larvae burrow into the soil to pupate. The hatched beetles eat in the same year about two to three weeks until they go to winter again in the ground.

Dissemination

The center of the distribution area is located in Southeastern Europe. In Central Europe the species is found only in the Czech Republic and Slovakia, Austria there are old messages Fund. In Hungary, the beetle and its larvae and mass occurrence can already be harmful. The species is probably realized in the propagation. Anyway, are new find news from Germany, Austria and the USA.