Now that there is a mosquito plague, the question arises whether residents of the province can also find more spiders in their homes. There would be more spiders walking around than in other years, and they would also be a lot thicker and larger than normal. What is going on? The born West Frisian spider enthusiast Peter Koomen answers.
It is a general fact: where there are insects, and therefore mosquitoes, there are spiders. Is the spider population increasing now that there is a mosquito plague?
“That’s difficult to say,” says Peter Koomen. The arachnologist and spider lover is only too happy to delve into the subject of spiders. According to the native West Frisian, no exact figures are kept about the number of spiders. “A spider plague is just like the economy: afterwards you can easily reconstruct what happened, how and why. This is difficult to predict in advance.”
Spider’s menu
Due to the warm late summer weather, there is still plenty of food to be found for insects. This means there are more insects and that is good for spiders, after all, it is their food. The more food for the spider, the bigger and fatter they become. The production of spider eggs also increases. When spiders carry many eggs, they appear a lot larger. They store those eggs in their bodies.
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Special eggs
According to Koomen, it is difficult to say whether there is a so-called spider plague in the province. However, he notes that the upcoming winter also plays a determining role in this. “If the winter is wet and mild, spider eggs will become moldy after laying and die.” In contrast to a cold and dry winter, most eggs will survive because of their special antifreeze layer. But it shouldn’t get too cold, because then most spiders will die anyway, says Koomen.
“You better not kill them, otherwise your house will be full of mosquitoes”
Tips
Koomen has some advice for people who see a spider in their home and would like to get rid of it. “Don’t kill! Then your house will be full of mosquitoes and other insects.” The best way to keep spiders out of your house is to keep windows and doors closed or to place a screen in front of a window. But says Koomen: “You are never more than one meter away from a spider. They are everywhere, including in crawl spaces and cavity walls, for example.”
Exterminators can do nothing other than keep spiders away, says the spider expert. Killing spiders is prohibited. They can rub a kind of soap on the windows, which makes it more difficult for spiders to build a web. They can also spread certain smells or sounds in the house that spiders hate.
Special spiders
There are plenty of special specimens in the province, says Peter Koomen. For example, he found 49 species during a backyard survey in Alkmaar. Most were house, garden and kitchen spiders. But Koomen also found the ‘little greenhouse spider’, which crawled over from the Mediterranean. This spider, measuring 3 to 4 millimeters, was first found in a garden center in 2015. The eight-legged animal probably came with a plant.
The ‘cave spiders’ are also appearing more and more often in North Holland. These spiders actually only live in caves, for example in Limburg. No explanation has yet been found for this, says spider enthusiast Koomen. “There is still plenty of research to be done about spiders. But others can do that, I am much too old for that,” he jokes.