Why are there more wasps in France in 2020?

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An increase in the number of wasps has been recorded by wasp destruction companies across the country, particularly in Bas-Rhin, Hauts-de-France and Ile-de-France; as well as in the Pays de la Loire and the Nord-Pas-de-Calais coast.Some had speculated that it could be linked to a drop in human activity due to confinement, or the hot temperatures observed this summer.

Read more: France’s wasp population much higher this summer

But the entomologist (expert in insects) Quentin Rome, from the Natural History Museum the National Museum of Natural History (MNHN) a explained the phenomenon to an information source 20 minutes, and suggested that the increase in enrollment is quite normal and related to conditions seen last year, rather than events in 2020.

He said, “This feeling of being overrun with wasps comes back every year. Last year I received requests for an interview on the same topic, although we are actually seeing a sharp decline in the wasp population.

“This is because in France, we have two species of wasps; Germanic and Common. They are both interested in our food, and are very present in urban and quasi-urban spaces. That’s why we feel like they overtake us every time we sit down to eat out.

So, has there been an increase?

Overall, yes. Estimates suggest that the wasp population changes frequently in France, fluctuating considerably from year to year. These are only estimates, said Mr Rome, because there are “few statistical studies that can accurately track populations.”

But, he said: “We estimate that in 2019 wasp populations had fallen by 300% compared to 2018. It is still too early to estimate for 2020, as we are in the middle of the season. wasps, but we can estimate closely, that time, that the populations increased five times compared to 2019. “

What impact is containment?

While some have suggested that containment could be the cause of the increase, Mr Rome disputed it.

He said: “I don’t really understand what it means to say that containment has had a positive impact on wasp populations. I would tend to say the opposite.

“Containment means we’ve spent a lot more time in our gardens, near parks… so much so that the wasp nests were detected earlier than usual. I have particularly noticed it in the Asian hornet, for which I am responsible for monitoring the population in France.

“I received pictures of nests from the first weeks of detention, which were young nests, or nests that previous years had not been found.

What about hot temperatures?

The actual temperature of our seasons is less important than temperature stability, said Mr Rome. Last winter was relatively mild, as was spring, meaning there were no peaks and troughs in temperature that could cause wasp problems.

Mr Rome said: “Of course, a very difficult winter can lead to an increase in wasp mortality, but they can withstand very low temperatures and frost. Stable temperatures are more important to them… peaks and non-seasonal changes can interrupt their [life] cycle.

“The winter heat, as we have seen in the south in recent years – such as 20 ° C at the end of December, followed by frost – risks waking up some king wasps, who will then have nothing to eat and who will probably die.

“Likewise, the late frost that we saw in the spring of 2019 in several regions of France also resulted in an increase in the mortality rate in queens.

Is it possible to peacefully coexist with wasps?

According to Mr. Rome, despite their threatening reputation, wasps are important for biodiversity.

He said: “We often hear about bees because they are pollinators. But many other insects do, too, including wasps. They are also insect predators and tend to concentrate on the most abundant ones, such as tree caterpillars. In this way, they help to regulate [the environment].

“I am therefore not in favor of a major destruction of the wasps that annoy us. Of course, a nest can be dangerous – when it’s in a passage, for example – and you have to hire a professional to get rid of it.

“But the solution to the wasps flying around our table is to give them part of our meal. A quarter of an hour before eating, place some fruit or meat about three to four meters from your table, then they will usually let you eat in peace. [after]. »

So is the increase this year good news for biodiversity?

Overall, the increase in wasp numbers this year is not just a sign of ‘good’ biodiversity, Mr Rome said, with many other factors also at play.

He explained, “It’s not that simple; the increase observed this year is linked to the weather, and a few years ago with more [wasps] and some with less. This is normal, nothing new or unusual.

“As with other species, on the whole they are dying, due to intensive agriculture. This trend is expected to continue this year. The rise of the Asian hornet is also bad news for bees, as they are prey.

“It has not rained” normally “in France for several years, to such an extent that the trees give less fruit and the flowers less nectar. This is likely to cause resource problems for many insects.

“This problem is not so important for wasps or the Asian hornet [though]because they find much of their food in our sugary foods. Other insects can do this too, but much less, and they prefer flowers.

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