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It is not only honey bees that are having a hard time - wild bees and other insects in particular are having a hard time
Photo: Friso Gentsch / dpa
Urban greenery in municipalities gives way to colorful flower meadows, ornamental plant breeders have recently committed themselves to the goal of being insect-friendly, roses and other garden plants, whose pistils and stamens bees like to visit, are in vogue.
And Baden-Württemberg has explicitly banned rock gardens, which are hostile to insects, by law.
Word has got around that Germany's insects, and especially pollinators, are suffering. The shocking findings of large-scale studies such as the one from Krefeld in 2016, according to which the mass of flying insects has decreased by almost three quarters over a period of around 27 years, have awakened environmentalists in many private gardeners and politicians. But as gratifying as the numerous initiatives, especially in urban areas, are - it is doubtful whether they will be enough to stop the decline of the numerous species and with them the plant world, says the agroecologist Andrée Hamm from the University of Bonn. Because the main problem is not the small gardens, but the large agricultural areas. "Cleared, blossom-free agricultural landscapes are to a large extent to blame for the decline of insects," says Hamm.
Making the agricultural landscape more insect-friendly is a Herculean task because of its sheer size.
It takes up about half of the federal territory.
Agricultural scientist Friedrich Longin from the University of Hohenheim in Stuttgart makes it clear how big the problem is: "The only large-scale cultivated plant that flowers is rapeseed." But it is susceptible to pests.
Farmers therefore spray insecticides often and several times.
The result: In the German monocultures almost nothing flies or crawls.
Because there is neither pollen nor nectar and if there is, it is sometimes toxic terrain for insects.
Fewer insects also mean less harvest
The extensive cherry and apple tree plantations in the Altes Land and on Lake Constance alone need countless pollinators in spring, otherwise their yields dwindle. A study by various US and Canadian researchers recently documented that the apple, blueberry and cherry harvests in the US are already limited by pollination. In future, fewer insects will fly and fewer fruits will hang on the branches. Several research projects are now trying to remedy the situation.
In their search for bee-friendly crops, a team led by Longin discovered buckwheat as an ally. It blooms from July to August, depending on the sowing in the blooming hole. "Then when there is no nectar in the gardens or in the fields and the aphids in the forest have already been milked for the forest honey," says Longin. He is currently testing the cultivation of twenty buckwheat varieties to find out which variety would be suitable in this country.
The Ministry for Rural Areas and Consumer Protection in Baden-Württemberg is funding the work.
"We help determine the diversity of insects," says Longin.
He has observed butterflies, various types of bees and flies on the white, delicate flowers.
Longin knows, however, that in future farmers will only sow buckwheat if customers like the small, angular grain.
Since it's gluten-free, it could be of interest to bakers, he hopes.
"As another flowering crop, the first chia variety for cultivation in Germany came onto the market in May," reports the agricultural scientist.
The black chia seeds are considered to be particularly nutrient-rich superfoods and are therefore really in vogue as an ingredient in rolls and snacks.
So far, however, they have come from South and Central America.
Another trend should help the bees: The Federal Research Institute for Cultivated Plants, the Julius Kühn Institute, recently got a group of experts for medicinal plants.
Because these crops from valerian to marigold achieve low yields, but high profits and they attract many insects.
The federal government had already set an increase in the cultivation of medicinal and aromatic plants as a target for 2020.
It should be 20,000 hectares by then.
The last time it was recorded in 2011, there were 13,000.
"We are seeing a steady increase," says Hamm.
With 125 species, the variety of medicinal and aromatic plants that can be used for cultural purposes is enormous.
Many medicinal plants attract insects
However, they have not found a place in the federal government's insect protection program.
"We need data to convince politicians," says Hamm.
That is why he and his colleagues are now recording the number of insects on herbs and medicinal plants.
With the naked eye you can see that caraway, chamomile and especially fennel are approached by many species of bees, beetles and butterflies.
But visitor frequency and pollination performance are unknown to nature.
»The flower architecture is decisive.
It needs a runway, and then the animal has to get the nectar with its proboscis. "
Andrée Hamm from the University of Bonn
That is why the researchers are currently collecting the little visitors on caraway seeds, fennel, savory, coriander and other crops. These regulars then dab it with glycerol gelatine and analyze the pollen that is stuck in the sticky mass. So they try to measure the respective share of the pollination.
»The flower architecture is decisive. It needs a runway, and then the animal has to get the nectar with its proboscis, ”says Hamm. This is why bumblebees avoid thyme. The sweet juice lies far too deep in the small goblets for the comparatively massive animals. The pale blue flax attracts honey bees, butterflies, bed bugs and beetles of various species. Butterflies, beetles, wasps and hoverflies can be seen on umbelliferous plants such as chives. "This diversity is in no way comparable to the local agricultural crops," Hamm describes an initial result.
The Federal Environment Ministry is funding the research project through the specialist agency for renewable raw materials.
At the end of this there should be a sort of ranking of which insects visit which medicinal and aromatic plants most frequently and pollinate them most efficiently.
What can be done for insects in city centers
The city administrators in Hessian Riedstadt also thought of the bees when they gradually replaced the well-known urban green - permanent green hedges and shrubs - with flower meadows from 2010 onwards.
There are now 1.3 hectares spread over 300 small areas.
Knauzias, Dost, cornflowers and poppies bloom on narrow strips between street and sidewalk, traffic islands and other small areas.
Horticultural workers sown a total of seventy different flowering plants.
The city administration would like to continue on this path.
If parking spaces or paths are newly created, they should be lined with regional flowering plants in the future, according to a new guideline.
"Unfortunately, we still don't understand very well why a plant is approached."
Andrea Dohm from the ornamental plant manufacturer Selecta one in Stuttgart
The biologist Karsten Mody from the Technical University of Darmstadt tested the effect of the urban flower meadows on insects. He counted the insects from spiders to cicadas and butterflies on 41 areas in Riedstadt and found that there were more than three times as many insects in total on the meadows. Almost all genera were represented more frequently, especially bedbugs, cicadas, beetles and butterflies. Last year Mody published his findings in the journal Plos One. "The conversion has a very positive effect on insect diversity," says Mody. “And, what was most convincing, maintenance is not as laborious as it is with trees. It is sufficient to mow the areas twice a year and leave sections where possible, as mowing always means stress for the insects. "
Darmstadt, too, has meanwhile converted 7.3 hectares of land, on which hedges and bushes previously grew, into flower meadows based on the Riedstadt model.
More blooming squares and stripes are to follow.
"The residents sometimes have to get used to it," says Mody.
Some people like the sight of permanent green better than a meadow with supposed weeds that turns brown from the dryness in late summer.
"But when we explain that this is better for the insects, everyone is very impressed."
Roses as friends of insects
After all, more and more people want to do something for bees. In garden centers, individual plants now carry the label "bee-friendly". "This is now very important for newly grown ornamental plants," reports breeding manager Andrea Dohm from the ornamental plant manufacturer Selecta one in Stuttgart, where petunias and carnations are mainly produced. “Unfortunately, we still don't understand very well why a plant is being approached.” The color and shape of the flowers seem less important than the scent that the insects perceive, but which differs from what we smell. So far, plant breeders have not been able to search specifically for hereditary traits for insect friendliness in the seed. They have to wait for their hybrids to bloom and see where the insects are going in the field. Until a new insect-friendly variety comes on the market,Several years go by.
It is a stroke of luck when something unusual happens, like on the Tantau test field in Uetersen in Schleswig-Holstein. Thousands of white, pink and yellow roses thrive there. “Thirteen years ago we noticed a little red on the test field because it was always swarmed by bees. We called it “bee pasture” and made the bees pasture range out of it about ten years ago, ”reports breeding manager Jens Krüger at the Tantau company.
But that was clearly ahead of the times. "It was bobbing around." The bee pasture almost fell out of the catalog when the insect deaths became an issue from 2017 onwards. “Insect-friendly roses are very popular now. We have to constantly increase the refinement numbers of the bee pasture series in order to meet the demand. We have even developed a logo for bee-friendly cultivars so that our customers can recognize such plants quickly and buy them in a targeted manner, ”reports Krüger. The trend towards insect-friendly flowers has changed their appearance: once roses were so densely filled that no bees could get to the flower vessels. 55 petals were considered the ideal size. “Now the pistil and stamens should be exposed. Because those who garden also want to be good for bees, «says Krüger.Incidentally, roses primarily provide protein-rich pollen that bees need to raise their brood.
So will Germany soon become a land of bees?
The number of beekeepers has also been increasing for years.
More than a thousand are active in the capital alone.
The proportion of domestic honey in the total honey consumption of Germans has risen to around 30 percent.
The wild bees are doing badly
Nevertheless, there is criticism of the current initiatives. The entomologist Michael Boppré from the University of Freiburg says: “All of these projects primarily benefit the honeybees, our pets, but not the insects as a whole. Because all other insects - with the exception of bees - need different food for the larval stage, often a specific herbaceous plant. «Those who only sow flowering plants for bees feed the bees. But humans even accelerate the decline of other insects because all species compete with each other, explains Boppré. Especially the specialists, including a number of wild bees that only have a single food crop, are disappearing.
This also includes such impressive animals as the blue gentian, whose larvae only live on the gentian. It seldom flies in the foothills of the Alps. »The measures are well meant, but not thought through to the end. We help generalists and eliminate the specialists, ”says Boppré. A general problem with many nature conservation measures: It was only in November 2019 that researchers reported that Natura 2000 protected areas did not protect the specialists among the butterflies well enough.
In addition to scattering flower mixtures intended for bees, the internationally known entomologist therefore urgently advises leaving natural areas that are already there, such as traffic islands and paths, to natural vegetation and only mowing them in sections once a year so that the habitat is »wild Wiese «persists. In addition, much more areas would have to be cultivated more extensively and others would have to be entirely reserved for nature. Regionally rare plants should be consciously preserved. “If you want to stop insect death, you have to stop plant death on a broad scale. Because that is the food. "
