At first glance, the blue-black carpenter bee (Xylocopa violacea) has little in common with the friendly Maya the bee. Among bees, this unusually large and dark species inspires respect from other animals and us humans thanks to its loud humming. The gentle giantess is actually quite harmless. Now a board of trustees has chosen her as “Wild Bee of the Year” for 2024 to draw attention to her special way of life.
Black and yellow ringed: The bodies of the carpenter bees (Xylocopa) are covered with predominantly black hairs and are noticeable due to their bluish shiny wings. The most widespread representative in this country is the blue-black carpenter bee (Xylocopa violacea). At two to three centimeters, the females are among the largest wild bees in Germany. Externally, the females of the southern carpenter bee (Xylocopa valga) look very similar, which was first detected in Germany in 2009 and has been spreading ever since. At 1.4 to 1.6 centimeters, its relative, the small carpenter bee (Xylocopa iris), is slightly smaller and only occurs sporadically in Alsace and Baden.
Blue-black carpenter bee spreads
A board of trustees has now named the blue-black carpenter bee “Wild Bee of the Year” for 2024. Last year the choice fell on the spring silk bee. The annual presentation of a particularly interesting species is intended to encourage people to get out into nature and observe these important flower pollinators in their habitat. Anyone who comes across blue-black carpenter bees during their foray can report this find to the board of trustees and thus help scientists with documentation. Even if the imposing appearance and loud humming of the “annual bee” can inspire respect, carpenter bees are gentle giants and are harmless.
In Germany, the blue-black carpenter bee is most commonly found in Baden-Württemberg. In the wake of climate change, the heat-loving species has expanded its range into the northern federal states and as far as Denmark in recent years and is therefore now found throughout Germany. Overall, however, the populations of wild bees, which are useful to us humans, remain threatened. The blue-black carpenter bee prefers to live in orchards, but can also be found in warm, sunny places in residential areas, such as on green facades. The females build their linear nests in old and dead wood from dead trees, house beams, fence posts or firewood. In order for the animals to gnaw the brood cells into the wood, it must be sufficiently crumbly, but not yet rotten. The blue-black carpenter bee is less picky when it comes to food: although it prefers butterflies and labiate plants, it collects pollen from over ten plant families
Peculiarity in reproduction
In late summer, the males and females of a generation of carpenter bees look for overwintering quarters in cavities in facades or between brick walls. Mating occurs in the following spring and the newly mated females build their nests from the end of April. Within just about two months, the larvae develop and live on the previously created supply of pollen and nectar. Like all solitary bees, the blue-black carpenter bee does not need the help of its fellow bees when building nests and caring for the brood. In most solitary wild bees, the female closes the entrance to the nest after laying her eggs and dies. However, the blue-black carpenter bee instead guards the unlocked nest entrance and witnesses the hatching of its offspring. It therefore represents a special feature.
Source: State Museum of Natural History Stuttgart