It seems as if the slug is advancing.

This summer you can encounter them much more than in other years on the bike path, next to the roadside or in the garden.

Allotment gardeners complain about eaten vegetables.

However, experts in conversation with NU.nl do not necessarily think that there are more slugs.

The animals are experiencing a great summer in terms of weather, making them more active and crossing your path more often anyway.

While we humans (usually) are fed up with a changeable summer like this year, slugs are flying the proverbial flag.

"This summer is very humid compared to previous years, when the summers were very dry," said a spokesperson for the ANEMOON foundation, which researches molluscs, among other things.

Paleontologist Jelle Reumer even calls it "the ideal summer" for the nudibranch.

"When I cycled to work, a bit out of town, I saw dozens of them on the bike path. The more it rains, the more active they are."

The ANEMOON spokesperson explains: "Snails use slime to move around. And to produce that slime, moisture is needed."

That is at least one explanation for their visibility at the moment, and perhaps the only one.

"We don't know whether there are also more slugs this year."

See also: Dutch spoiled by warm summers: wet July was traditionally Dutch

No slug count

There is in fact no 'measuring network' to count slugs, as there are, for example, insect counts and the annual garden bird count.

So it is guesswork as to the actual numbers of slugs.

"It is quite possible that the numbers have really increased. In any case, the circumstances have recently been favorable for reproduction," said the spokesperson.

The slug eggs laid in abundance in the spring have now made it into adult slugs.

Regardless of whether humanity needs a slug count, such an activity would not even be possible, says scientist Reumer.

"If you were to organize it on a weekend that it hasn't rained for two weeks, you won't find one, and on a weekend like now you stumble over it."

That makes counting and comparing with other years unrealistic.

Nudibranch can burrow in dry summer

Where do the slugs actually stay in summers that are dry?

ANEMOON Foundation: "In dry weather, they search until they return to more humid conditions. This can be under stones or tree trunks, for example. But they can also burrow deeply."

Reumer remembers a fieldwork expedition in Crete years ago: "It is normally very dry there, but one day it rained heavily. The vineyard-like snails suddenly crawled over the road in hundreds. People followed them. "

Incidentally, this Dutch "ideal summer" is short-lived for many nudibranchs.

Ironically, the very freedom they get through the rain often means their end.

The aforementioned dozens of slugs that Reumer saw on the bike path on their way to work turned out to be largely killed: "No one tells those animals that they should not cross that road."

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