Pear fruit cutter

Pear fruit cutter
Pear fruit cutter ( Rhynchites giganteus ), female
Systematics
Class : Insects (Insecta) Order : Beetle (Coleoptera) Subordination : Polyphaga Family : Leaf roller (Attelabidae) Genre : Rhynchites Type : Pear fruit cutter
Scientific name
Rhynchites giganteus
( Krynicki , 1832)

The pear fruit cutter ( Rhynchites giganteus , syn .: Rhynchites versicolor ) is a beetle from the family of leaf rollers , subfamily Triebstecher or Rhynchitinae, which belongs to the weevils in the broader sense. The genus Rhynchites is represented in Central Europe with eight species . Rhynchites giganteus belongs to the subgenus Epirhynchites , which is represented in Europe with five species. Of these, apart from the pear fruit cutter from Central Europe, there are also the two very similar speciesRhynchites auratus and Rhynchites lenaeus reported.

The name of the genus Rhynchites is from Altgr. ῥύγχος, rhýnchos, "trunk" derived and refers to the long trunk. The species name giganteus ( Latin ) means “gigantic”. The name is not very meaningful as there are similar species that can reach the same size. On average, however, it is relatively large.

The beetle can be harmful to pears to a limited extent. The female shows a simple form of brood care .

Fig. 1: Wing cover (end of the body on the right)
	Fig. 3: side view
Fig. 2: Proboscis , male above , female below	Fig. 4: Right front claw

Characteristics of the beetle

The beetle is metallic coppery with purple or green shading; The tip of the trunk, antennae and tarsi are blackened. The beetles reach lengths of just under seven to nine millimeters (without a trunk).

The head is extended like a trunk forward, the trunk slightly bent downwards. A fine central keel runs between the deflection of the antennae and the base of the trunk. The mouthparts are at the tip of the trunk. The upper jaws of the female have permanent external teeth, which give the tip of the proboscis a star-shaped appearance when the upper jaws are closed when viewed from above (Fig. 2, bottom).

The eleven-link antennae are not kneeled as in the weevils in the narrower sense, but end as culled as with these. In the female, they are turned in about the middle of the trunk, in the male further forward. The first and second antennae are of the same length (Fig. 2).

The pronotum is seamlessly fused with the front breast. Seen from above, this is a little longer than it is wide. The males, like the females, do not have a protruding thorn over the front hips.

The wing covers are very wrinkled. They are long haired, the hair is uniformly long and uniformly strongly sloping backwards. This distinguishes the species from Rhynchites auratus , in which the hairs are less uniformly long and stick out more steeply. The dots standing in rows are significantly larger than the dots that are disordered in the unevenly wide intervals between the rows. In addition, they are not round, but elongated and can converge near the label (Fig. 1). There is no short row of dots next to the tag that ends a little behind the tag (without a row of scutellar dots).

The splints have one small end spike in the male and two in the female. The tarsi are all four-limbed, the third limb is deeply split and bilobed to accommodate the claw limb. The claws are not fused at the base and are toothed on the inside (Fig. 4).

biology

The beetle can be found in Central Europe from April to September on various trees from the rose family , especially fruit trees and hawthorn species . The species can be harmful to pear crops. The eggs are laid in the fruit, the latter made to fall off by cutting the stems.

For the countries of the former Soviet Union , the pear pest is given for biology: The species overwinters in the larval stage or as an adult in the ground. The adults appear before the pears start to bloom. They feed on buds, later on flowers, leaves, young shoots and fruits. The white and oval eggs are laid in June – July. To do this, the females gnaw a passage into the fruit, widen the end to form an egg chamber and lay a single egg there. Then they close the passage with chewed pulp. A groove is then gnawed on the surface of the fruit around the egg chamber. Several eggs can be laid per fruit. Finally, the fruit stalk is gnawed. Up to 160 eggs can be laid. The infected fruits fall to the ground.

The larvae hatch after eight to twelve days. The larvae take thirty to sixty days to develop. They feed on semen and the sperm chamber. The last larval stage leaves the fruit to pupate. The doll's chamber is laid out in the ground at a depth of about 15 cm. During the winter and the next summer, the development is interrupted ( diapause ). Pupation and hatching of the adults takes place in the following autumn, but the beetles remain in the pupal chamber until the next spring.

Solitary pear trees and those on the edge of pear tree cultures are mainly infested.

distribution

The range of the species includes southern and central Europe, Turkey and northern Iran, within the former Soviet Union the beetle is widespread.

literature

• Heinz joy , Karl Wilhelm Harde , Gustav Adolf Lohse (ed.): The beetles of Central Europe . tape 10 : Bruchidae – Curculionidae 1 . Goecke & Evers , Krefeld 1981, ISBN 3-87263-029-6 .
• Hans Gønget: The Nemonychidae, Anthribidae and Attelabidae (Coleoptera) of Northern Europe. Brill, Leiden / Boston 2003, ISBN 90-04-13265-1 . ( Fauna Entomologica Scandinavica. Volume 38)
• Eduard Voss: Monograph of the Rhynchitinen - Tribus Rhynchitini. 2. Generic group Rhynchitina . In: Coleopterological review. Issue 24, 1938 ( PDF; 3.1 MB ).

Individual evidence

1. ↑ ^{a b c} Rhynchites giganteus in Fauna Europaea. Retrieved September 23, 2011
2. ↑ Epirhynchites (subgenus) in Fauna Europaea. Retrieved September 6, 2011
3. ↑ Sigmund Schenkling: Explanation of the scientific beetle names.
4. ↑ ^{a b c d e f} Interactive Agricultural Ecological Atlas of Russia and Neighboring Countries

Web links

Commons : Pear Fruit Cutter  - Album with pictures, videos and audio files

• Image of males and females