Osmia

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Osmia
Horned mason bee (Osmia cornuta), female collecting pollen from cowflower (Taraxacum)

Horned mason bee ( Osmia cornuta ), female collecting pollen from cowflower ( Taraxacum )

Systematics
Order : Hymenoptera (Hymenoptera)
Superfamily : Apoidea
without rank: Bees (Apiformes)
Family : Megachilidae
Subfamily : Megachilinae
Genre : Osmia
Scientific name
Osmia
Tank , 1806

Osmia is a genus of bees from the Megachilidae family, they are mostly mason bees in German, some species are called snail-shell bees . The genus is distributed Holarctic , it is particularly species-rich in the Mediterranean area.

A total of 347 species have been described, most of them (206 species) in the Palaearctic. Individual species occur in the Oriental and Neotropical . Some authors count the holey bees ( Heriades ) and scissor bees ( Chelostoma ) as a subgenus of Osmia.

features

Osmia bees are about 6 to 16 millimeters tall and have a stocky build. Sometimes they are very hairy, but sometimes only a little. The abdomen is often almost bald and has light-colored hair ties. The females have a conspicuous belly brush (hair on the belly side), which can be colored red, black or white. This belly brush is used to transport pollen (so-called "belly collector"). Males have appendages typical of the species on the abdomen and the end of the abdomen.

Way of life

Osmia are solitary, nest-building bees. Most species only have one generation a year. Some species fly early in spring (e.g. O. cornuta , O. bicolor ), others later, still others only in midsummer (e.g. O. spinulosa ). The males hatch one to two weeks before the females (proteranderia).

Nesting way

Mason bees nest in very different ways, often with mineral mortar or vegetable mortar (chewed pieces of leaf). According to Westrich (p. 162) the following nesting methods can be classified (without species that are included in Heriades ):

  • In existing cavities: O. bicornis, O. brevicornis, O. cornuta, niveata, O. gallarum, O. leaiana, O. tuberculata .
  • In empty snail shells: O. andrenoides, O. aurulenta, O. bicolor, O. rufohirta, O. spinulosa, O. viridana . Some of these species are also called "snail shell bees".
  • In dead wood in self- dug cavities: O. pillicornis .
  • Dug itself in sandy soil: O. maritima .

Mason bees collect pollen, which may also contain nectar, in their brood cells. When there is enough pollen supply for a larva, an egg is placed in the cell and the cell is closed. As a rule, several cells are built one behind the other. Unfertilized eggs are laid in the last cells, from which males develop. The individual cells are normally separated from one another by partitions; only in the Schöterich mason bee ( Osmia brevicornis ) are the larvae (8 to 23 larvae) and pollen stores without dividing walls in a large cell in which the larvae develop together. In some species the larva overwinters, in some the finished bee (" imago" ).

habitat

Some species are mainly found in forest areas (e.g. O. pilicornis ), others on south-facing rocky slopes and dry grasslands (e.g. O. andrenoides ). Osmia bicornis occurs in very different habitats (forest edges, clearings, field hedges, but also in localities). Osmia alticola occurs in the Alps on alpine meadows and meadows. Osmia cornuta is particularly common in settlement areas and sometimes even occurs in the center of large cities. As a rule, no high population densities are achieved. Some species can be promoted very well through artificial nesting aids (e.g. Osmia bicornis through nesting tubes).

Sources of pollen

Some types of Osmia collect pollen from different plant families (polylectic), for example Osmia bicornis and O. bicolor . Other species specialize in pollen from individual families or genera (oligolectic). O. cerinihidis collects wax flowers ( Cerinthe ); O. adunca and O. anthocopoides collect pollen from Natterkopf (Echium); O. mitis collects bluebells ( Campanula ); O. leaiana , O. niveata, O. spinulosa and O. villosa collect pollen from sunflower plants.

Pseudocopulation

In some Osmia species ( O. tarentina, O. mustelina, O. kohli, O. rufa ) in the Mediterranean area, the males pollinate orchid flowers ( Ophrys ), which attract them by imitating females. The males carry out a so-called " pseudocopulation " in which they receive the pollen and bring it to the next flower, which also mimics a female.

Parasites

Systematics

The genus Osmia belongs to the Osmiini tribe with over 1000 species and currently 15 genera, many of which do not occur in Central Europe.

Other genera of this tribe in the native fauna are: Chelostoma , Heriades and Hoplitis (the latter is, however, still counted as Osmia by Westrich ). According to Müller, the following subgenera of Osmia are currently represented in the Palaearctic (number of species described in brackets): Allosmia (9), Erythrosmia (4), Helicosmia (68), Hemiosmia (7), Hoplosmia ( 21), Melanosmia (19) , Metallinella (1), Nasutosmia (2), Neosmia (8), Osmia s. st. (27), Pyrosmia (30), Tergosmia (7).

Hoplosmia used to be considered a separate genus by some authors.

Native species

(after, not completely)

See also

Individual evidence

  1. ↑ a b c d e f Erwin Scheuchl & Willner, Wolfgang: Pocket dictionary of wild bees in Central Europe . 1st edition. Quelle & Meyer, Wiebelsheim, Hunsrück 2016, ISBN 978-3-494-01653-5 .
  2. ↑ a b c A. Müller: Palaearctic Osmiine Bees - Genus Osmia. 2019, accessed January 2, 2020 (American English).
  3. ↑ a b c d e Paul Westrich: The wild bees of Germany . Stuttgart 2018, ISBN 3-8186-0123-2 , pp. 161-184, 592 .
  4. ^ P. Westrich: The wild bees of Germany . 2018, p. 168, 600 .
  5. ↑ Solitary bee species: Mason bees (Osmia). Retrieved January 4, 2020 .
  6. ↑ HF Paulus & C. Gack: On the pseudocopulation and pollination in the genus Ophrys (Orchidaceae) of Sardinia and Corsica . In: Jber. Naturwiss. Ver. Wuppertal . tape 48 , 1995, pp. 188-227 .
  7. ↑ Christophe J. Praz, Andreas Müller, Bryan N. Danforth, Terry L. Griswold, Alex Widmer: Phylogeny and biogeography of bees of the tribe Osmiini (Hymenoptera: Megachilidae) . In: Molecular Phylogenetics and Evolution . tape 49 , no. 1 , October 2008, ISSN  1095-9513 , p. 185-197 , PMID 18675365 .
  8. ↑ Ch. D. Michener: Bees of the World . 2nd Edition. The Johns Hopkins University Press, 2007, pp. 448-490 .