Wooden bees

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Wooden bees
Xylocopa iris, female

Xylocopa iris , female

Systematics
Order : Hymenoptera (Hymenoptera)
Superfamily : Apoidea
without rank: Bees (Apiformes)
Family : Real bees (Apidae)
Genre : Wooden bees
Scientific name
Xylocopa
Latreille , 1802
Large wooden bee ( Xylocopa violacea )
Wooden bee stealing nectar from a winter jasmine
Wooden bee before the start of a broad-leaved flat pea flower
Wooden bee building a nest in dead wood of weeping willow, Radebeul 2010

The wood bees ( Xylocopa ; composed of the Greek ξύλον xylon 'wood' and κόπτειν koptein 'cut', i.e. 'those who cut wood') are a genus from the family of the real bees (Apidae) within the bees . Eight species of them occur in Europe , in Central Europe there are three. The animals have their German as well as their scientific generic name, as most species create their nesting paths in wood. They can cause damage to built-in wood and are therefore combated in houses and objects made of wood, particularly in the United States .

features

Wooden bees reach a body length of 14 to 28 millimeters. They can be easily distinguished from other species of bees by their bumblebee-like body and mostly black hair and their blackish, purple iridescent wings. In Central Europe the group can only be confused with the females of Megachile parietina , which show a certain similarity. However, these have the belly brush typical of Megachile species.

In Central Europe, Xylocopa iris can be easily distinguished from the other two occurring species, which are difficult to determine on the basis of external characteristics.

Some species have a mammary gland that sits on the back at the back of the thorax and is believed to be reproductive.

Occurrence

These heat-loving bees have their main distribution in the tropics and subtropics and are distributed worldwide, except in the far north, in very numerous and differently colored species. In Central Europe they fly in one generation from April to August.

Way of life

When visiting flowers, wooden bees act as “nectar robbers” in many cases. With their mandibles and their sturdy proboscis they can pierce flower tubes in order to suck up the nectar by the shortest possible route . At large butterfly flowers like those of wisteria and grass pea but they use the normal access via boat and pen away from the front and so act as pollinators. They also collect pollen, which they not only transport with the hairbrushes on the rails and the heel of the hind legs, but also for the most part in their crop . With a comb on the maxilla they can comb pollen out of the hair on the front legs and swallow it. The species occurring in Central Europe collect nectar from different plants ( polylectia ), but prefer butterflies and mint plants . Males have been observed sleeping in self-dug holes in the ground.

Unlike most other bees, wooden bees build their nests themselves. They gnaw these with their strong mandibles into wood (mostly dead wood that is already crumbly due to fungal attack ) or into stems containing marrow . In thin branches or stakes, only one passage is usually gnawed. Parallel corridors that emanate from the main corridor are hollowed out in thicker wood. The individual brood cells lie one behind the other in a line, are separated by dividing walls made of pieces of wood or marrow and coated with a waterproof secretion . A mixture of pollen, head gland secretion and nectar in the form of a loaf of bread is the provisions for the brood and lies lengthways along the cell wall. The egg is laid on the long side of the provisions, with the female squeezing herself between the provisions and the cell wall when laying the eggs. When the nesting site is ready, only the nesting passages are closed, but not the nest entrance. A nest is about five centimeters deep and kinks along the direction of the wood grain at a right angle with a length of ten to fifteen centimeters. If a nest is used by several bees, it can be up to three meters long.

Pupation takes place after just one and a half to two months without the formation of a cocoon . The adults of the next generation appear very quickly, but the animals fly in only one generation in the temperate latitudes. They fly during most of the warm season and finally overwinter individually or in small groups in crevices, self-dug holes in the ground or their nests. The mating takes place only after the wintering in spring. What is unusual for solitary bees is the long lifespan of the females, which then create their nests well into the summer and even live long enough for them to experience the adults of their brood and live with them in the nest. This is otherwise only known from bees of the genera Halictus , Lasioglossum and the closely related Keulhorn bees ( Ceratina ). Social behavior has been observed in some species, but has not yet been proven in the Central European species.

species

There are the following types:

Individual evidence

  1. ^ Xylocopa. FaunaEuropaea, accessed May 6, 2009 .
  2. ↑ * List of species on www.discoverlife.org , accessed April 10, 2020
  3. ↑ MS Engel, AS Alqarni, MA Shebl, J. Iqbal, IA Hinojosa-Diaz: A new species of the carpenter bee genus Xylocopa from the Sarawat Mountains in southwestern Saudi Arabia (Hymenoptera: Apidae) . In: ZooKeys . No. 716, 2017, pp. 29–41. doi : 10.3897 / zookeys.716.21150 . PMID 29290706 . PMC 5740427 (free full text).
  4. ↑ Reinholdreiber: Observations of the southern wooden bee Xylocopa valga Gerstaecker, 1872 (Hymenoptera: Apidae, Xylocopinae) in southern Baden and in Alsace (France, Alsace, Département Haut-Rhin) . In: Ampulex , Vol. 7, 2015, pp. 26–31, (PDF) .

literature

  • Andreas Müller, Albert Krebs, Felix Amiet: Bees. Central European species, way of life, observation. Naturbuch-Verlag, Augsburg 1997, ISBN 3-89440-241-5 .

Web links

Commons : Wood bees  - Collection of images, videos and audio files