Years ago, after driving on a short highway, your car windscreen was regularly black from the insects that flew against it. Now that is different, there are far fewer mosquitoes and other insects left behind on your car.
Last October was a record month, explains Manger. “It has never been this warm in October, all over the world, so that is very special.” This heat allows insects to continue flying for longer. Insects that normally ‘should have fledged long ago’ are still buzzing because of the exceptionally mild autumn.
In addition, there are also insects that can always be found in the Netherlands in winter anyway. Manger mentions winter damselflies as an example.
This warming is therefore not necessarily a problem for all insects: “For most insects this is not so bad, for butterflies and dragonflies, for example, it is not such a drama in itself,” says Manger. In fact, while there are certainly species that have disappeared due to the higher temperatures, there are also species that are actually improving. “There are also animals that come from the south, that come here because of the heat and can survive here just fine.”
The drier summers associated with warming, on the other hand, do pose a danger, according to Manger. “The summers and springs are drier than before and the winters are much wetter. So what you get is a drying out in the summer.” Although it does occasionally rain heavily in the summer, it also evaporates much faster, he says. “So it seems like it’s going very well, but that’s not the case because it just dries up.”
Daan Drukker of the EIS knowledge center for insects agrees on the impact of the prolonged dry summers on insects. Species that depend on water such as streams, fens and high groundwater are particularly affected by this effect of climate change. This is easy to measure with kites such as the moon dragonfly and fen glazier because these creatures are closely monitored.
Still, the impact of the current warm weather on insects ‘cannot be measured’, says Drukker. Neither he nor his colleagues notice much of “confused” species. It is suspected that this warm autumn will not have much influence on insect populations.
But the fact that southern species are increasingly showing themselves in the north is ‘as clear as possible’, says Drukker. Among the insects that attract our northern country are many grasshoppers, he says, such as the southern pointed head and the southern tree locust. That is not necessarily a cause for concern, because the southern species are not harmful to the rest of the biodiversity. Because their enemies also crawl to the north, the southern guests are kept in check. That way they don’t become invasive.
The other side of the coin is that due to the increasing heat, the species that called Drenthe home are increasingly being pushed to colder areas, Drukker explains. For example, there are species that need water all summer long, but no longer have access to it because puddles and other small waters dry up.