On the sunny slope in pensioner Karsten Klenke’s garden, it hums and hums on this warm spring day. There are numerous wild bees around – including fur bees, sand bees and mason bees. The former police officer and amateur biologist has created an insect paradise on his property with many different flowering plants. Nesting aids made of wood or clay hang on the house wall.

This support is enormously important for insects – because: “In Germany, at least half of the wild bee species are endangered and that is currently not getting any better due to climate change,” says biology professor Alexandra-Maria Klein from the University of Freiburg, referring to World Bee Day on May 20th. In addition to a lack of fodder plants and a lack of nesting opportunities, the animals suffered from pesticides and the sometimes extreme weather conditions. Pesticides are agents against weeds, insect pests and fungal diseases on crops.

Bumblebees are easy to observe

According to Klein, there are around 570 species of wild bees in Germany. If you are out in nature and want to see some, then your best chance is with earth bumblebees or rock bumblebees with their distinctive red bottoms. These bumblebees live together in so-called states, which makes sightings more likely. The majority of other wild bees live alone, such as the fairly common red mason bee.

Since many wild bee species nest in the ground, the widespread bee hotels are only an option for less than ten percent of the species, says the professor of nature conservation and landscape ecology. “However, bee houses can be very helpful in educational work.” With hinged models you can easily show what the bees and larvae are doing.

Honey bees stay in the hive in bad weather

During pollination, wild bees fill the niches that are not occupied by honey bees. “The honey bee is highly complex. When a worker flies out of the hive in the morning and notices: ‘Pfff, it’s too cold,’ then she tells her sisters: ‘Just don’t go out today.’ Then these bees won’t fly.” But many wild bees are out and about early in the year and even in unfavorable weather conditions. “They can’t afford to stay in their house. They live alone.”

In order for wild bees to survive, diverse habitats are important, emphasizes the professor. “Anyone who has a garden or balcony can grow a flowering meadow for bees and other insects.”

The biologist Johann-Christoph Kornmilch has researched what helps wild bees in a nationwide pilot project. Accordingly, flower strips whose plant species are adapted to native bees make sense in agriculture. Large, specially created nesting mounds have also proven successful.

“I would like to see a nationwide safety net for bees,” says the expert. Communities or farmers could get involved in this and ensure bee-friendly structures through which the animals can spread. In cities, it helps if people mow until the flowering period has passed, says Kornmilch.

“Wild bees are simply incredibly beautiful”

Since the various species of wild bees are on the move all year round, it is important that something is always blooming, emphasizes hobby researcher Klenke. “I promote diversity,” says the 77-year-old, who has counted around 38 species in his garden. There is a lot of flight activity at the stone troughs, where wild bees fly in and out of numerous holes in the ground. Klenke also sees the loss of habitat as the greatest threat to wild bees. Due to pure grass farming in many fields, more and more forage plants that offer nectar and pollen were missing.

Klenke acquired specialist knowledge over the years after becoming interested in bees and bumblebees at a young age. Professor Klein is also fascinated by her research objects. Every day you see something new and there is so much to discover, she says. “And if you look at them a little larger or take a photo of them, you realize: wild bees are simply incredibly beautiful.”