In midsummer, it seems that bumblebees under lime trees die out again and again.
But what is actually behind this phenomenon?
Every year around midsummer people are horrified when they find the first dead bumblebees under linden trees.
The mass extinction causes bewilderment, anger and, above all, often perplexity.
Are Pesticides To Blame?
Was it climate change or even surface sealing?
We explain why the bumblebees die in this particular place and how everyone can help.
Dead bumblebees under linden trees: This is behind the phenomenon of bumblebees dying
There are many rumors about the death of bumblebees in midsummer, half-truths are spread and for a long time it was not even clear whether it was
really such a strange phenomenon or just a natural process
.
There is talk of the fact that nature fans will
find masses of dead bumblebees
again and again from midsummer
, mainly under linden trees
.
Once in the media, numerous discussions sparked off, explanations were given and refuted.
As the Naturschutzbund Deutschland (NABU) reports, it has now been refuted, for example, that bumblebees die just as often in other places.
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Dead bumblebees under linden trees: theories and evidence
So there actually seems to be a connection between linden trees and dead bumblebees.
Just why
For example, earlier theories were based on toxins in the linden trees, others based on a coincidental correlation between natural bumblebee death and the flowering of certain linden trees.
According to NABU, studies by the University of Münster in the 1990s showed that the animals found were by no means old, but rather in their prime.
NABU has also given the all-clear for the theory of poisonous nectar, as neither poisonous sugar nor mannose could be found in the nectar.
But what are the big, small fluff balls dying of and, above all, why?
+
What is behind the death of bumblebees in midsummer?
© Imago
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Dead bumblebees under linden trees: that's why they die
The findings that NABU provides on this question make us sad.
Because the bumblebees simply starve to death under the trees
.
According to NABU, researchers from Münster measured the animals' sugar reserves and realized that there were hardly any energy reserves left.
Queens are the exception, after all, they ensure that the bumblebees will continue to exist for the next year.
Normal bumblebees do not build up large stocks and then have a problem at some point.
Bumblebees usually die under
Krimlinden
or
silver linden
.
In order to understand the connection with bumblebees, one must be able to classify the whole thing:
Summer linden trees bloom in June
Winter linden trees bloom until around mid-July
Dutch linden trees bloom around the same time or before the winter linden tree
Crimean linden and silver linden bloom until the end of July or even into August
If you look at the landscape and your own garden at the end of July, you will notice that fruit trees and vegetables have generally not bloomed for a long time.
With the exception of hibiscus and a few others, there are no more flowers on shrubs.
The food supply is dwindling rapidly despite the best summer weather.
The theory according to NABU: the
animals, already weakened
by the
reduced food supply
, find food on the linden trees, but are often too weak to take in it.
In addition, according to NABU, there is also a certain pressure of
competition
with other bumblebee colonies.
And this is exactly where animal fans can help, because the solution is very simple!
+
The death of bumblebees in autumn often makes animal lovers sad (symbol picture).
© Blickwinkel / Imago
Dead bumblebees under linden trees: Here's how you can help
So we are almost back to the beginning and with the question: is
surface sealing
to blame?
Indeed.
If you live in greener areas with enough wild growth, you will certainly discover many plants that attract bumblebees and other insects even in midsummer.
However, concrete often prevails, especially in new development areas and large cities, gardens are getting smaller and smaller, even if many nature fans make an honest effort to compensate.
But if the efforts increase, the food supply for insects will slowly grow again in late summer.
That works on the balcony too.
Therefore, in this case: Long live the weeds!
Flowering meadows are sometimes mowed too early to prevent the seeds from ripening.
But these flowers in particular are important.
You should therefore not mow wildflower meadows too early in the garden either.
Basically everyone can do something for the bumblebees:
Plant a wildflower meadow instead of sealing the ground with gravel gardens
Do not mow the flower meadows too early (if necessary, seeds can be removed)
Leave blooming "weeds" (or at least smaller parts of them) until the insect colonies would die naturally anyway
Many late-blooming plants can also be integrated on balconies and roof terraces
Many plants do not bloom until July, you just have to know them.
For example, sunflowers, splendid notches, spherical thistle, marigold, sedum plant, coneflower, wild and red angelica, artichokes, ivy, asters, common heather and a few more provide food even after many other plants have long since put their energy into seeds.
In addition, there are some remontant flowers that bloom again under good conditions, including adder's head, wild mallow and many more.
Incidentally, the most popular in the author's garden at the moment: vetch and borage, closely followed by ornamental onion.
A garden for bumblebees and other animals does not have to be overgrown and untidy.
The taller perennials in particular are a great eye-catcher and can be sown in a very orderly manner.
Flowers like the marigold also bloom almost continuously from May.
A nice side effect: while the neighboring gardens slowly become bare and dreary after the harvest, your garden will continue to bloom for a long time.
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List of rubric lists: © Imago