Earth bees are extremely diverse insects that have adapted to very specific habitats. Many of the species use specific plants as a food source. They are threatened by various factors and should be encouraged more in the garden, because their utility is of great importance.

Ground bees are not aggressive and therefore do not pose a threat

Table of Contents

Show all
  1. the essentials in brief
  2. Characteristics
  3. Sand bees in the garden
  4. protect sand bees
  5. Look
  6. lifestyle and development
  7. Natural enemies
  8. species and habitat
  9. Harmful or useful?
  10. Nature conservation in Germany
  11. frequently asked Questions

    12. the essentials in brief

    • Soil bees or sand bees are soil-dwelling bees
    • Ground bees should not be fought as they are useful and - sadly - increasingly rare
    • Sand bees can be carefully driven away by permanently shading your burrow and/or slightly moistening the entrances

    What are ground bees?

    Ground bees are called ground bees. They represent the genus of sand bees (Andrena) and are represented worldwide with more than 1,500 species. About 150 sand bees are native to Central Europe, of which 116 species have been observed in Germany.

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    What to do with sand bees in the garden?

    Sand bees are often responsible for holes in the lawn. They can also dig tunnels in the substrate of flower pots or window boxes (€16.99) so that they can be observed on balconies and terraces in spring. However, there is no reason to fight it, as the insects do not pose a threat.

    Only in extreme exceptional cases, for example when large numbers of animals nest near kindergartens, are deterrence measures considered. Relocating the nests requires a special permit. With all measures and methods, the survival of the sand bees has the highest priority. The use of insecticides or home remedies is neither recommended nor necessary.

    moisten cavities

    If you want to get rid of sand bees, you can gently moisten the burrow entrances. Make sure the animals don't drown. If the habitat becomes too humid, sand bees will stop building their burrows and look for an alternative place. This method only works if the females are still busy digging. If they have already sealed the entrances, the larval development is in full swing. From then on, you may no longer water the breeding grounds, as you endanger the offspring.

    withdraw sun

    You can also drive away sand bees by permanent shading. Set up a parasol or stretch an awning over the free area that is inhabited by a female. It quickly notices that the living conditions are no longer optimal and breaks off the cave construction. This method is only recommended if the female has not yet closed the entrances. If there are already eggs in the nest, development is endangered by the lack of warmth.

    Ground bees do not feel comfortable in the shade

    protect sand bees

    Instead of getting rid of the beneficial insects, enjoy the species in your garden. You can be sure that your garden is one of the most natural and special living spaces. If you want to do something to protect the earth bees, you can redesign the garden and balcony accordingly and plant them in a natural way. The more varied the habitat, the greater the chance of successful colonization by sand bees.

    Create small habitats

    Set up flower boxes (€16.99) or pots filled with sand to offer the sand bees a suitable substrate for nest building. The container should be placed in a sun-exposed place in the garden or on the balcony, as the animals need warmth.

    If you have enough space in the garden, you can also enclose a small area with hollow blocks or quarry stones and fill them with about 50 to 100 centimeters of drifting sand or loamy sand. As an alternative to stones, you can also use deadwood trunks and thus offer several specialized insect species a habitat.

    tips

    If you have wide eaves, you can prepare a bed of sand right next to the house. Here the nest boxes are optimally protected from rain.

    keep paths open

    Small trails in the garden offer some species particularly good conditions. The ground is kept open by kicks. The bryony sand bee prefers such slightly compacted areas. Think about whether all the paths in the garden really need to be paved. If there is no alternative, you can lay the paving stones with the largest possible joints. Even then, sand bees still find good opportunities for nest building.

    plant food sources

    If the habitat is right, all that is missing is the equipment of the garden with suitable nectar plants. The more diverse you design the garden, the more species feel addressed. In order to lure rarer species into the garden, special forage plants must be available. The bryony sand bee nests in gardens where male specimens of various bryony species also grow.

    tips

    It is worth taking a closer look at the food spectrum of sand bees. Many species prefer plants that require a minimum of maintenance to grow.

    What do ground bees look like?

    Sand bees are particularly furry and less conspicuously colored

    These wild bees look very different. There are very small species that are five millimeters long. The large sand bees reach a length of 16 millimeters. Their basic coloring varies from black to black-red and can seldom have a metallic sheen.

    Most earth bees have furry hair and are recognizable by a light-colored fringe of hair on the abdomen. The hind legs have hairbrushes that sand bees use to collect pollen from the stamens. Various characteristics can be used to distinguish between males and females.

    male female
    buttocks without a lock of hair with lock of hair
    face bright spotted velvety hairy pit
    sensor 13 links 12 links

    Difference between ground wasps and ground bees

    Earth wasps show aggressive behavior and thus appear obtrusive. Sand bees, on the other hand, are shy and withdrawn. But both insects only sting when threatened. A characteristic distinguishing feature is the hair, because earth wasps are often only hairy in places and can thus be clearly distinguished from the furry hairy earth bees.

    The insects can be distinguished not only by their appearance, but also by way of life and nest building. While the earth wasp usually only uses one entrance to the underground cave, the earth bee digs several holes. They usually use the cave for many years. Earth wasps are already looking for a new quarters the following year.

    lifestyle and development

    Unlike the honey bee, sand bees do not form a colony. They live as loners. The female is solely responsible for building her nest and caring for her offspring. Rarely, several females form nest aggregations in the immediate vicinity. However, shared use is the exception. The native species are active in spring and mainly fly between April and June. There are few species that can be observed until late summer.

    nest building

    In the spring, they mate and lay their eggs in tunnels that are five to 60 centimeters deep. The females dig their own burrows by compacting the soil into lumps with saliva and carrying them out of the burrow. The clods of earth are piled up around the entrance.

    During the construction process, clods of earth often roll back into the corridor, which then have to be carried outside again. Downpours support the construction work. The clods of earth are moistened and harden after drying, creating a stable entrance.

    Sand bees do not actually build honeycombs, but branch nests that have a vertical main entrance. This branches into short side passages, each of which ends in a brood cell. The nest is mostly arranged vertically. The female places pollen and nectar in each brood cell so that the larvae that later hatch will find enough food. An egg is laid in each brood cell before it is sealed.

    From larva to bee

    When the larvae hatch, they feed on the food provided in the shelter of the burrow. This is sufficient until pupation, because the mother does not take care of the brood. Many bee larvae, such as the common sand bee, develop a protective cocoon that they spin from their own glandular secretions.

    When the new generation hatches depends on the climatic conditions. If the winters are mild, the adult sand bees come out of their burrows in late summer. In Germany, sand bees do not hatch until the following spring, with males breaking out of their cocoons before the females. They try to mate with them directly.

    food

    Sand bees are very specialized when it comes to food. Their menu includes pollen and nectar from asparagus, cinquefoils and speedwells, but also from many daisy, umbelliferous and cruciferous plants or lepidopteran plants. Many species use different food sources. The red-furred sand bee prefers to fly on currant and gooseberry bushes, but also accepts other food plants. About half of the native ground bees fly exclusively on certain nectar plants.

    • Willow Sand Bee: Pollen and nectar from willows
    • Brine sand bee: specialized in bryony species
    • Knautia Sand Bee: field scabious, pigeon scabious

    winter

    Many of the bees native to Germany pupate in late summer, but spend the cold season in the shelter of the cocoon. In the coming spring, the insects hatch and crawl out of their burrows. The parents do not survive the winter.

    Natural enemies

    Crab spiders love to eat bees

    There are many enemies that can be fatal to sand bees. Predators benefit from the protein-rich insects, while parasites and fungi attack sand bees and their larvae in other ways.

    robber

    Predators capture sand bees as adult insects. These include crab spiders, which lie in wait on the flowers of their prey and wait for a visit. Digger wasps can also pose a threat to ground bees. These paralyze the insects with a sting and then suck them out.

    Other predators:

    • different predator fly species
    • Types of assassin bugs
    • insectivorous birds such as bee-eaters

    parasites

    Sand bees are endangered by oil beetles, fan wing beetles and wool hover beetles. Many cuckoo bees such as blood bees or wasp bees lay their eggs in the underground nests of sand bees. In this way, cuckoo bees save themselves the search for food, because their larvae feed on pollen and nectar in the brood cells. Such parasitic species have specialized in a few host animals. You are dependent on its existence and continued existence.

    digression

    This is how sand bees protect themselves against parasites

    Some sand bee species such as the Scottish ground bee and other species that are not native to Germany live communally. Usually several sister females live together in one nest. This is started by a female and extended by the sisters. In this way, latecomers save themselves the time-consuming digging of passages in particularly hard soil. In addition, the females living in the tunnels can protect the brood from invading parasites. Solitary sand bees that leave their nest after laying their eggs do not enjoy this protection.

    fungi and bacteria

    In the closed brood cells, the spread of mold or bacteria can have devastating effects. Therefore, sand bees are very picky about their choice of nesting sites. They avoid habitats with dense vegetation or excessive waterlogging, as these offer optimal living conditions for fungal spores and bacteria. Instead, the insects seek out warm and dry environments.

    These habitats are unattractive for fungi and bacteria:

    • dusty sidewalks
    • sparsely vegetated and sunlit embankments
    • loosely overgrown and sunny lawns

    species and habitat

    As the name suggests, the bicolored sand bee can be recognized by its two colors (brown and yellow).

    Sand bee species are predominantly found on the northern continents. Most earth bees prefer habitats that feature dry and warm conditions. Unlike mason bees, which like to nest in window frames, sand bees look for loose substrates to create a breeding site. Open soils with sandy spots provide optimal conditions for building caves. Soils with a high proportion of clay make it difficult to build nest cavities.

    Because of their main distribution in sandy habitats, the species got their German name. They differ greatly in their appearance and show differences in flight times, food spectrum and habitat.

    Scientific name flight time nesting place food status
    Iridescent blue sand bee Andrena agilissima May - July steep walls cruciferous Rare
    Bicolored sand bee Andrea bicolor March - August Forest edges, bushes, gardens, parks bluebells often
    Grey-black sand bee Andrena cineraria April May Gravel pits, river landscapes, forest edges, gardens different plants often
    Common Sand Bee andrena flavipes April - August Forest edges, hedges, pits, gardens Umbelliferae and daisies, buttercups and rose plants often
    Scottish ground bee Andrena scotica April May Dry grassland, near-natural meadows, gravel areas different plants often

    Harmful or useful?

    Sand bees do not pose a threat to humans, nor are they harmful to other creatures or plants. Even if many people fear the mass appearance of bees in spring, there is no need to worry. Sand bees do not display aggressive behavior. They are shy and do not defend their nests.

    The males are unable to sting. Although the females have a stinger, they rarely use it in dangerous situations. However, the stinger is too weak to penetrate human skin. You can let children and pets play safely in the garden and enjoy the ecological benefits of sand bees.

    Why sand bees are useful:

    • pollinate different plants
    • increase the harvest of fruits and vegetables
    • indicate valuable habitats as they occur in threatened habitats
    • loosen up the soil

    Nature conservation in Germany

    Ground bees also pollinate flowers and are therefore particularly important for us and our environment

    Although most native sand bee species are common, earth bees are protected. The bee population is declining dramatically. If the pollinating insects die out, many plants will not be able to reproduce. According to the Federal Nature Conservation Act, capturing, disturbing or killing animals is prohibited. The protection also extends to the nests, which may not be removed, destroyed or relocated without an exemption. Some Andrena species are already considered endangered as their habitats are becoming scarce. Andrena marginata is even endangered.

    Changing environmental conditions and human intervention have devastating consequences for sand bees.

    Sand bees in danger

    Many sand bee species are still common in Germany, but the situation can change quickly. There are natural nesting sites on poor, dry grassland with a sandy subsoil. Forest fires, floods or landslides continuously create open sites that are populated by sand bees. More and more of these habitats are being destroyed, so that the insects have to reorient themselves. They colonize sites close to humans. But human intervention ensures that such habitats are becoming rare. Gravel and sand paths are covered with tar and areas are improved.

    This endangers sand bees:

    • Shortage of food supply
    • ignorance of the people
    • monotonous garden design

    frequently asked Questions

    Do ground bees make honey?

    Sand bees collect pollen and nectar, but they do not produce honey from them. The insects use plant nectar sources as a food source for themselves and to create a food base for their offspring. To do this, they equip each brood cell with pollen before laying eggs in order to lay their eggs on it. The larvae have to feed on this until pupation, because they only leave the burrow the following year.

    When do ground bees hatch?

    If the brood cavity is warm enough, the larvae hatch shortly after the eggs are laid.They stay in the shelter of the underground tunnels until they pupate and usually overwinter in their cocoons. Only in the following spring do the young insects bite through their protective covering and free themselves from the closed burrows. Most sand bee species fly between April and June.

    Are ground bees dangerous?

    There is no danger from the very differently colored species. Sand bees do not defend their nests. The female leaves after laying her eggs. If it finds itself in a dangerous situation, it tries to defend itself. For humans, however, these defense methods are completely harmless.

    Do ground bees have a stinger?

    Males are stingless. Only the females have a sting with which they can sting when threatened. The sting is not dangerous to humans as the delicate spines cannot pierce through the skin. You don't have to fear a sting from the romping dog.

    How old do sand bees get?

    After males have mated, they die. For the females, the most difficult part of life now begins, because they build the nest box and provide the individual brood cells with food. About four weeks after the mating activities, the females also die. The larvae hibernate in their cocoon to crawl out of the brood cavity next spring. Then the spectacle begins again.

    What do you do against ground bees?

    Control is out of the question for species protection reasons. Removing and destroying the nests is just as punishable as capturing and killing the insects. Relocation requires a special permit.

Category:

Animals in the garden