Many hobby gardeners are startled when they discover a black-colored bumblebee-like insect in their garden. They suspect that this is a dangerous hornet. There is no need to panic as this species proves to be an interesting garden visitor in need of protection.

The black hornet is actually a bee

Table of Contents

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  1. the essentials in brief
  2. Black Bumblebee Hornet
  3. lifestyle and development
  4. food
  5. Toxic or dangerous?
  6. frequently asked Questions

    7. the essentials in brief

    • The great black hornet is a species of bee. It is referred to as a blue-black, large, or violet carpenter bee. The species is unmistakable due to its striking body features reminiscent of a bumblebee.
    • As a warmth-loving species, the carpenter bee is mainly found in southern Europe. Their area is increasingly expanding to the north.
    • The solitary bees live in dead wood or the earth. They are among the early-flying pollinators and are active until midsummer. Suitable niches are sought out for hibernation.
    • Carpenter bees do not specialize in plants. Wisteria is a frequently visited tree. The insects are considered harmless.

    Who is the black hornet?

    The black bee is impressively large

    Anyone who has seen this insect will never forget it. With a bumblebee-like body and the conspicuous size of between 20 and 28 millimeters, the animal is almost frightening. In fact, it is the largest native bee species that does not belong to either bumblebees or hornets. It is the blue-black carpenter bee with scientific name Xylocopa violacea.

    Typical and noticeable features:

    • blue wings
    • blue-black body
    • black hair

    distribution

    The insect has many names such as blue, violet or large carpenter bee. The species is native to southern and central Europe. Until the 1980s, the distribution area in Germany extended to the Upper Rhine plain. Since 2003, the carpenter bee has been increasingly spreading northwards. Today it can be observed as far away as Schleswig-Holstein and partly in southern Sweden.

    Frequency in Germany

    While the carpenter bee was classified as critically endangered in the 1980s, the population has since recovered. By giving up meadow orchards, nature was able to develop independently, resulting in more deadwood. At the same time, the warmth-loving species is favored by rising temperatures, allowing it to spread north. But even in warmer areas of Germany, suitable nesting sites are scarce, so the carpenter bee rarely occurs there.

    This is where the carpenter bee lives:

    • on meadow orchards with dead trees
    • at structurally rich forest edges
    • in natural gardens and parks

    Are there multiple types?

    In the warmer regions within the German-speaking region, you can observe three types of carpenter bees between April and August. They are difficult to tell apart based on their physical characteristics. With a length of 15 to 18 millimeters, the small carpenter bee is smaller than its relatives. The blue-black carpenter bee is usually between 20 and 25 millimeters in size, while the eastern carpenter bee reaches a body length of 22 to 28 millimeters.

    German distribution nesting place
    Xylocopa violacea Big carpenter bee Austria, Switzerland, Germany rotten deadwood and thicker stems
    Xylocopa valga Eastern carpenter bee Austria, Switzerland, Germany rotten deadwood
    Xylocopa iris Little carpenter bee Austria Switzerland; lost in Germany pithy stems, diameter: 11-16 mm

    lifestyle and development

    Carpenter bees in Central Europe live solitarily. They dig their own burrows in brittle deadwood or pulpy plant stalks, using the insects' strong upper jaws. Depending on the thickness of the tissue, carpenter bees gnaw a tunnel or a complete system of several parallel tunnels branching off from a main tunnel. While the nest entrance remains open, carpenter bees close the brood cells in their nest tunnels with a substance made from wood or plant pulp particles and saliva. They are lined with a waterproof substance so that the brood is optimally protected.

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    development

    When the warm rays of the sun herald spring, carpenter bees wake up from hibernation and start looking for a partner. It takes no longer than two months for the egg to develop into an adult carpenter bee. Insects produce one generation per year. Females live an unusually long time for bees, so they get to know their offspring themselves. This survivability is otherwise known from furrow and club horn bees.

    The impressive growlers like sunlit habitats with a wide variety of flowers and heavy deadwood.

    This is how carpenter bees overwinter

    Before hibernating, carpenter bees spend the rest of the year exploring their surroundings. For the hibernation, they retreat to their birth nests or look for other hiding places. Their hibernation strategy differs from the concept pursued by hornets:

    carpenter bee hornet
    Who hibernates? both genders mated young queens
    What is needed? mostly above-ground, sheltered crevices low-light, rain-protected cavities
    Where do you overwinter? Cracks in the wall, burrows, own nests Tree cavities, attics, bird nest boxes, deadwood
    How do you overwinter? individually or in small groups individually, rarely in small groups

    What do carpenter bees feed on?

    Carpenter bees also collect pollen and nectar

    Carpenter bees feed on pollen and nectar from various plants. Species that bloom early are of great importance, since the insects are busy building their nests as early as April. In the crop and with the help of the hind legs, they transport the pollen to their nests to feed the brood. Their diet is diverse and should persist into midsummer:

    Carpenter bees prefer large-flowered plants:

    • mints: Winter jasmine, sage, Ziest
    • daisy family: meadow knapweed, thistles
    • borage family: Adderhead
    • papilionaceous plants: Chinese and Japanese Wisteria, Vetchpeas

    tips

    Carpenter bees are considered to be site-loyal and always return to the old breeding grounds. Therefore, you should not make intensive changes in your garden.

    digression

    Intelligent beings?

    If the flowers are large enough, the carpenter bees use the normal entry point through the flower opening. They touch the flower organs and act as pollinators. Most of the pollen is transported with her crop. Occasionally, the insects use a different method of acquiring food.

    As so-called nectar robbers, carpenter bees use their powerful mouthparts to gnaw through the flower tube. This is how they get the coveted nectar of deep buds that their long tongues can't get through in the normal way. In this form, the insects scavenge for food without fulfilling the consideration of pollination.

    Toxic and dangerous?

    The carpenter bee has a stinger that it uses to inject its venom into a potential attacker. This happens extremely rarely because the species is not aggressive. A sting is only to be feared if you crush or otherwise threaten the insect.

    tips

    If you collect wild herbs for your own use, you should leave the bouquets in the fresh air for a while before washing them and then shake them out well. This way hidden guests can get away and you avoid a sting.

    frequently asked Questions

    How can I help the black hornet?

    Rotten wood offers shelter to the black hornet

    Carpenter bees depend on deadwood, which becomes rarer in tidy gardens, forests and fields. Well-intentioned clean-up work destroys the valuable habitat of the carpenter bee. Leave trunks from dead trees or create a pile of thick trunks to provide a retreat for the impressive species. With a species-rich range of daisy, lepidopteran and labiate plants, you offer the insect important food.

    Design Tips:

    • put rotten stumps on a stone slab if the ground is wet
    • lay out dead tree trunks on dry sandy soil
    • Tie dead branches to trees at an angle
    • Combine early bloomers and summer bloomers

    A strange black hornet, about two centimeters tall, has settled in our half-timbered house. Like a woodworm, it bores thick holes in the beams so that sawdust falls out. What can we do against it?

    Carpenter bees do not stop at half-timbered houses when the wood has become brittle as a result of the natural aging process. If your building has been inhabited, this is an indicator of aging. It represents an ideal nesting place. To prevent such an "infestation", you should protect the wood from weathering. Treat it with stains (€66.50) and varnish to deter carpenter bees. Avoid damaging the wood with saw cuts or nail holes. Such cavities are readily populated.

    Stopping colonization that has already started:

    1. Place fruit tree stumps or pieces of old logs nearby
    2. Drill holes as an incentive for new colonization
    3. Cover entry holes in the beam

    What are these giant black hornets that appear in Turkey or Croatia?

    There are several species of the hornet genus that can reach impressive sizes. The Asian hornet (Vespula mandarinia) attracted particular attention. The species reaches dimensions between 27 and 55 millimeters and is characterized by a predominantly black abdomen with a broad yellow band. However, supposed sightings of this giant hornet in Europe are confusion with other species, since this insect is found in East and Southeast Asia:

    • Oriental hornet (Vespula orientalis) lives in Southeast Europe, e.g. Turkey
    • Vespa velutina (colloquially: Asian hornet) was introduced to Europe

    How do carpenter bees collect their nectar?

    Females collect pollen mainly in their crops but also with their hind legs. It crawls into the nest up to the brood cell and turns to face the entrance. Pollen is removed by cleaning the hind legs. The female solidifies the particles on the ground using her head and mouthparts. Sometimes it rotates several times before all the pollen is cleaned off and piled up.

    How do carpenter bees process the collected nectar?

    The females mix the pollen particle by particle with honey until a paste is formed. This is deposited in a separate passage parallel to the nest entrance. The color of the paste differs depending on the nectar collected. It varies between brown, dark red, dark green and beige.

Category:

Animals in the garden