Wasp season actually started on January 1 this year. “Do you remember when it was exceptionally warm?” says Arnold van Vliet, biologist at Wageningen University. ‘The first wasp queens probably woke up then. They started building their nests and with the spring being warm and dry they have been successful in raising their larvae. That means there will be a lot of wasps soon.’
Van Vliet was the first to start at the beginning of July signaled that this could turn out to be an exceptionally good summer for the wasp. The biologist keeps in touch with wasp fighters every year and they told him that relatively many reports of nuisance had been received. Also according to the website observation.nlwhere everyone can report their wildlife observations, an exceptional number of wasps were seen in the first half of the year.
So, since they will be everywhere this summer: a short wasp science course.
1. The wasp does not exist
There will be no less than 408 species of wasps in front of. Those wasps belong to different families: you have the golden wasps and the pincer wasps, the pear-headed wasps and the club wasps. ‘The species that we encounter most often and that cause the most nuisance are the common wasp and the German wasp,’ says Van Vliet. Those are the wasps that scour the terraces for sweets. They are also called ‘lemonade wasps’.
2. Wasps are sun worshipers
The first half of the year was particularly dry and warm. That is beneficial for the wasp. When the queens wake up, they go in search of nectar. They have it easier in dry and sunny weather, because there are many flowering plants to be found.
Soon a queen starts building a nest: she gnaws on wood, for example from a fence, and makes the typical, paper-like wasp’s nest. Then she lays her eggs. Once the larvae hatch from the egg, the queen has to look for insects to feed them. ‘The first time she is on her own,’ says Van Vliet. ‘It makes a difference if she can easily get hold of insects. When it is warm and dry, there are more insects and they therefore use less energy.’ It leads to the rapid expansion of the wasp family.
3. Wasps only get cravings for ice cream and lemonade later in the season
Until about mid-summer, the workers are busy feeding the youngest generation. ‘They catch insects, cut them into pieces and feed them to the larvae,’ says Van Vliet. ‘As a reward, they get sweeteners back from those larvae.’ So they don’t have to look elsewhere for sweets.
But at some point the nest matures and there are no more larvae. Then the workers have nothing more to do. The holiday season starts and that includes good food: on our terraces.
4. Lemongrass, cloves and geranium keep wasps (a little) at bay
How do you keep wasps away? from a American study a 2012 study found that certain essential oils can keep wasps at bay. When the smell of lemongrass, cloves or geranium arose from a wasp trap, there was a 70 percent decrease in the number of wasps caught.
Yet Van Vliet doubts whether this works so well in practice. “When I bought some of those oils myself, I couldn’t keep wasps away. Let alone when you just put down a bowl with water and cloves.’
What works best according to Van Vliet: do not use sweets on the terrace. And have wasp nests removed in the vicinity – although he also thinks we should be cautious about that. ‘Wasps also make a positive contribution: they trap flies, mosquitoes and spiders’, says Van Vliet. ‘A worker bee catches about 1.5 insects per hour.’
5. Wasps are useful
One of the advocates of the wasp is the British ecologist Seirian Sumner. With some colleagues she put in a row what use can the wasp have for humans.
So to start with, they catch other insects. This can come in handy in agriculture, where they can be used as biological control agents. Much more environmentally friendly than poison.
Wasps are also pollinators. Although the larvae feed on insects, adult wasps search for nectar. According to Sumner, there are 164 plant species worldwide that are completely dependent on the wasp for pollination.
In addition, we can eat wasps and their larvae. In Japan, for example, they are a delicacy. The fried insects are a more efficient source of protein than, for example, cow meat: they take up relatively less space, require less water and do not emit as much nitrogen.
Even the wasp venom, which makes a sting so painful, can be useful: it contains antibiotics. This keeps the prey fresh and free from disease. Humans too, perhaps. For example, the venom of a wasp from Brazil has already been shown to be effective against a bacterium that had become resistant to various other drugs.
6. Only the queen hibernates (but that may change)
Everything comes to an end, including wasp season. When it gets colder, the males and workers die and the queens look for a hibernation place. At least, that’s how it went until now. ‘Climate change could well change this,’ says Wageningen researcher Van Vliet.
According to him, there are colonies of the German wasp and the common wasp in New Zealand hibernate in their entirety. ‘Then they continue to expand the nest the following year,’ says Van Vliet. ‘This can create huge wasp nests, up to 4 meters high.’