Purple apple fruit cutter
| Purple apple fruit cutter | ||||||||||||
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Illustration of a purple apple fruit cutter |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Rhynchites bacchus | ||||||||||||
| ( Linnaeus , 1758) |
The purple apple fruit cutter ( Rhynchites bacchus ) is a beetle from the family of leaf rollers (Attelabidae), which belongs to the superfamily Curculionoidea . The related reddish-brown apple cucumber ( Caenorhinus aequatus ) has a similar way of life in Central Europe , but it can be distinguished by its different color. The similarly colored pear fruit cutter ( Rhynchites giganteus ) is also easily distinguishable due to its significantly larger body size.
features
The beetle is about 4.5 to 6.5 millimeters long. The body is stocky with parallel side wing covers ( elytra ) with clear front corners ( "shoulders") and significantly narrower neck plate (pronotum), which is a little wider than long. The trunk is longer than the pronotum (about one and a half times as long in the female, slightly shorter in the male), it is cylindrical and straight in the female, and slightly curved in the male. Striking is a central (medinan) keel in the basal half, which is bounded on both sides by a dotted furrow. The trunk is wider (widened) towards the front, stronger in the female than in the male. The pronotum and the elytra have relatively loose, coarse point pits. The beetle is striking because of its color. It is strongly metallic, shiny purple, sometimes metallic green with a purple sheen. The legs also have a metallic sheen, the antennas are colored black. The entire top is covered with long, fine red-brown hair, which is, however, quite inconspicuous.
Way of life
The larva of the species develops in fruit systems of woody rose plants , especially fruit trees. In addition to apples, apricots, peaches, cherries and plums, sloes are also documented, and there is further information on quince and the fruits of hawthorn and clout medlar . The female eats a niche in the developing young fruit in March or April, in which it lays one or more eggs. It then gnaws through the fruit stalk so that the fruit plant wilts and falls off. With some types of fruit, such as B. apples and apricots, the fruit stalk is only partially severed. Here the dried fruit plant initially remains hanging (similar to the Monilinia fruit mummies) and only falls to the ground in autumn. It is believed that the beetle also infects fruits with this fungal disease, which are believed to help them break down the pulp. The larvae are cannibalistic, so that in the case of multiple occupancy only one remains. The adult beetles also eat buds and leaves. The larva first eats the pulp, then the ovules. The fully grown larvae (they are then 6 to 8.5 millimeters long and colored white with a light brown head capsule) leave the fruit and pupate in a pupa chamber in the ground. Some of the larvae pupate immediately, come outside in late summer of the same year and eat on fruit tree leaves; they later overwinter under bark scales and in cracks in the trunk. Other larvae of the same population remain in the ground as old larvae (prepupa), overwinter at this stage and only pupate in the following summer. The pupal stage takes about two weeks to develop. The beetles are quite able to fly and are occasionally caught in light traps at night.
distribution
The species lives in Europe from the Baltic States and Poland to the Mediterranean area. It is absent in Scandinavia, but is considered extinct on the British Isles. It also lives in North Africa, Asia Minor and Western Central Asia, it occurs in Iran and the Caucasus.
Economic importance
The purple apple fruit cutter is in warmer countries such as z. B. in the Mediterranean area and in southern Ukraine a dreaded pest in fruit growing, which in earlier times could destroy entire harvests. It occurs in Central Europe, but is rare and has no particular economic significance here.
swell
- GA Lohse: 2nd subfamily Rhynchitinae. In: H. Freude, KW Harde, GA Lohse (Ed.): Die Käfer Mitteleuropas. Volume 10. Goecke and Evers Verlag, Krefeld.
- Hans Gonget: The Nemonychidae, Anthribidae and Attelabidae (Coleoptera) of Northern Europe. Fauna Entomologica Scandinavica, Vol. 38. Brill Academic Publishers (Leiden).
- Interactive Agricultural Ecological Atlas of Russia and Neighboring Countries
- T. de Stefani (1918): Rhynchites bacchus, a Coleopteron injurious to Apples, Apricots and Plums, in Sicily. Bulletin of the Bureau of Agricultural Intelligence and Plant Diseases Vol. 9 No. 3 pp. 402