Friday 24 July 2015

Carpenter bee - Xylocopa pubescens Spinola, 1838 - Cyprus

Xylocopa pubescens is a species of large carpenter bee. Females form nests by excavation with their mandibles, often in dead or soft wood. X. pubescens is commonly found in areas extending from India to Northeast, Cyprus and West Africa. It must reside in these warm climates because it requires a minimum ambient temperature of 18 °C (64 °F) in order to forage.

A common area of study in X. pubescens is its dominance hierarchy and guarding behavior. Colonies start and end with female takeover, either by daughters of the dominant female or by foreign intruders. There is only one reproductively active female in a colony at a time who suppresses the reproduction of other females in the nest. Males hold individual territories which females enter to mate. When an intruder enters another male's territory, the male responds aggressively.

X. pubescens is polylectic, so it forages on many species of plants. It forages on some plants for nectar when preparing bee bread during ontogenesis and forages on others for pollen to feed offspring. Pheromones from Dufour's gland are vital to mark flowers previously visited and also to mark nests so that the foraging bees know where to return. X. pubescens is known to be an effective pollinator, often more effective than honeybees, but it is not commonly used in today's agricultural settings

Carpenter bees
 (the genus Xylocopa in the subfamily Xylocopinae) are large bees distributed worldwide. Some 500 species of carpenter bees are in the 31 subgenera. Their common name is because nearly all species build their nests in burrows in dead wood, bamboo, or structural timbers (except those in the subgenus Proxylocopa, which nest in the ground). Members of the related tribe Ceratinini are sometimes referred to as "small carpenter bees".
Carpenter bees are traditionally considered solitary bees, though some species have simple social nests in which mothers and daughters may cohabit. However, even solitary species tend to be gregarious, and often several nest near each other. When females cohabit, a division of labor between them occurs sometimes, where one female may spend most of her time as a guard within the nest, motionless and near the entrance, while another female spends most of her time foraging for provisions.
Carpenter bees make nests by tunneling into wood, vibrating their bodies as they rasp their mandibles against the wood, each nest having a single entrance which may have many adjacent tunnels. The entrance is often a perfectly circular hole measuring about 16 mm (0.63 in) on the underside of a beam, bench, or tree limb. Carpenter bees do not eat wood. They discard the bits of wood, or reuse particles to build partitions between cells. The tunnel functions as a nursery for brood and storage for the pollen/nectar upon which the brood subsists. The provision masses of some species are among the most complex in shape of any group of bees; whereas most bees fill their brood cells with a soupy mass, and others form simple spheroidal pollen masses, Xylocopa species form elongated and carefully sculpted masses that have several projections which keep the bulk of the mass from coming into contact with the cell walls, sometimes resembling an irregular caltrop. The eggs are very large relative to the size of the female, and are some of the largest eggs among all insects.[8]
Two very different mating systems appear to be common in carpenter bees, and often this can be determined simply by examining specimens of the males of any given species. Species in which the males have large eyes are characterized by a mating system where the males either search for females by patrolling, or by hovering and waiting for passing females, which they then pursue. In the other mating system, the males often have very small heads, but a large, hypertrophied glandular reservoir is in the mesosoma, which releases pheromones into the airstream behind the male while it flies or hovers. The pheromone advertises the presence of the male to females
From Wikipedia, the free encyclopedia
Photos Nicosia, Geri by George Konstantinou

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