Osmia Bicornis — Wikipedia

Female redsmia. A horn is visible
below the left antenna.

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Species

Synonyms

• Bee bicornis (Linné, 1758) ^{[ first ]}
• Apis to roof (Linné, 1758) ^{[ first ]}
• Osmia Rufa (Linné, 1758) ^{[ first ]}

L’ Redhead Osmie , Osmia bicornis , is a kind of solitary bees spread in Europe of the Megachilidae family, of the genus Osm . It has disappeared from intensive agriculture areas but is well present in urban areas. His French name comes from his old scientific name synonymous: Osmia Rufa (Linnaeus, 1758).

• Female: the female with a size of 10-12 mm is larger than the male. She wears ^{[ 2 ]} Black hair on the head, gray-yellow on the thorax, brown-clair in Roux on the first three abdominal and black tergites on the last. Below the abdomen, it wears a yellowish ventral brush, for the transport of pollen. On the forehead, it wears two clear, truncated “horns”, absent in the male. These are two growths, much shorter than the antennas, appearing on the Clypeus, above the mandibles.
• Male: The male recognizes himself by his yellowish hairs on the forehead, with white toupet on the face and the antennas longer and thinner than the female. He does not wear “horns”. The coloring of the rest of the body is similar to that of the female.

Osmia bicornis is close to Osmia Cornuta , the cornuated osmia. Alain Ramel ^{[ 3 ]} distinguishes them from the following criteria:

Redus osmie is widespread in Europe. It is one of the most common lonely bees, especially in urban areas.

Habitat: It is present in the gardens, hollow paths, gravel pits or woods.

Head of a female Osmia bicornis , with Corne du Clypeus, according to a modified drawing of Tasei ^{[ 4 ]}

Couple. Both have 3 red tergites and the end of the black abdomen. The male has longer antennas and the female has small “horns” on the forehead

Osmia bicornis male, large antennas, yellowish hairs on the forehead

Redrus osmie is activated from March to June ^{[ 2 ]} , in general after Osmia Cornuta . The males come out first, from the first sweet days of March. The females appear 10-15 days later but remain active until the end of June, mid-July. The flight period of males is much shorter than that of females (about 15 days, according to Tasei ^{[ 5 ]} 1973)

After their appearance, males feed on the nectar of flowers and gather on nesting sites, such as hollow brick batteries or old huts. They patrol near the entrance to the nesting galleries while waiting for the females. When these start to emerge, a strong rivalry settles between them. Females only mate once. Mating lasts 5-10 minutes. Males only live 2 to 3 weeks.

Open nest of red -haired osmia. The center cell contains “bee bread” (pollen + nectar) and an egg

Once fertilized, the female is looking for an adequate nesting place, often the same as the one where she was born. She prefers long cavities from 0.5 to 1 cm In diameter, in old beetle galleries or galleries made in clay by other hymenoptera. She will also easily occupy nest boxes made up of bamboo tubes or holes pierced in wooden blocks. Before adopting a gallery, she inspects it meticulously and possibly clears the remains of cells of the previous year. Cleaning is done backwards.

The female uses clay as a building material. She searches in nature a damp corner of earth, scratches the ground with the legs, takes a clay dumpling that she kneads with saliva. She makes a small ball of 2 mm of diameter that she transports in the nest where she will work it as mortar.

The female builds a first partition, then delimits the future cell by building a “door step”. This is the draft of the second partition which has the shape of a crescent or a mud ring ^{[ 5 ]} . The osmie files a reserve of pollen and nectar. Pollen, harvested on the kittens of willows, hazelnuts or oaks, is transported on the ventral brush. The nectar, harvested on renuncular, papavulated, rosacea, etc., is transported in the jabot. The osmie penetrates the head first into the nest, regurgite the nectar and cups the “bee bread” with its forehead. She then back down to the entrance, turns around and slides the abdomen into the cell to unload the pollen by scraping her brush with her legs. When the cell is half full, after 10 to 30 trips, the female lays an egg and completes the front wall with clay. She will therefore shape, day after day, a dozen cells. The entrance to the nest is ultimately closed by a massive clay partition.

In the latest cells, the female lays non -fertilized eggs that will give males and will be the first to be released the following year. The deeper cells contain fertilized eggs that will give females.

• The egg cycle → Larve → Nymphe → Imago

The egg is elongated and curved and makes 2 to 4 mm . The segmentation is more and more apparent as you get closer to hatching. It occurs about ten days after laying.

The larva fixed on the food reserves, feeds by curling strongly downwards. After one to two weeks, she stands out from her base and turns. It takes 20 to 30 days for the 4 ^{It is} larval stadium be reached.

When food provisions are exhausted, the larva measures from 9 to 13 mm . She then begins to spin her cocoon.
The cocoon wires line the cell with a compact purple and dark brown layer. After spinning the cocoon, the larva lies on the back and remains motionless until the nymphale moult. This nymphosis occurs late July-early August. For a few days the nymph remains entirely white, then the eyes become pink and their color continues to darken for two to three weeks. The pigmentation of the nymph continues for several days.

The last step is the birth of the imago which generally occurs before winter. It will remain inside the protective cocoon until flight moment in March of the following year.

The mortality rate is very high in Osmia bicornis , of the order of 60% of the eggs laid ^{[ 4 ]} . According to Tasei observations ^{[ 4 ]} , ravages in osmia nests are caused by molds, a hymenoptera Melittobia acates Walk. and a diptery, Cacoxenus investigator Loew.

Redus osmie is not threatened.

THE Osmia bicornis And O. Cucky are raised by arboriculturalists for the pollination of fruit trees. They are more effective than domestic bees to pollinate almond trees that bloom very early in the season.

Osmies are very peaceful. If we do with gentleness, there is no risk of being bitten by females. The males have no dart.

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