The sun is shining again and that means not only cozy barbecues and ice cream, but also ants. The way to stop the itchy critters? According to the Internet: sidewalk chalk. But experts think otherwise.
One stroke would be enough to stop a whole line of ants. Useful when camping, in the garden or if you want to keep the bugs out of the house. But while it’s being marketed on the Internet as the hack against ants, experts say that’s just a little too good to be true.
Odor trail interrupted
The theory behind this method of controlling ants is that the chalk interrupts a scent trail. The ants use that scent trail to get to food, says professor of entomology.
“Ants’ nests have all kinds of scouts; they explore the environment. If those find a place that is interesting, because there is a food source, they take a little bit of food back to the nest.” On their way back to the nest, they each deposit a piece of a pheromone, a small molecule.
‘Small thumb’
With that, the ants make a path. Professor: “A bit like little thumb did with breadcrumbs, they do it with a scent signal.” By the way, that scent signal is impossible for humans to smell, because our noses are not sharp enough.
“In the nest, they tell the others that something is very interesting. Then some walk along to that food source. Those also along that existing trail lay even more of the scent trail.” That scent trail gets bigger and bigger. “That’s actually the direction blinker,” professor explains. “The more of the scent trail there is, the stronger the ants’ reaction is to follow it.”
Path disrupting
So the ants use that scent trail to guide each other to the right spot, but it can be disrupted. Professor: “That could be because an animal has walked by, a footprint has come up on the trail or the ground has been churned up. Then they are momentarily confused.”
“But if it’s a very strong signal of ‘there’s something to get there,’ they’ll start looking around the disturbance until they pick up the trail again. So then they lay the trail there.”
Does chalk interrupt?
But does sidewalk chalk disrupt that scent trail? Certainly, says ant expert Peter Boer. The ant then encounters a “strange smell” and doesn’t know what to do. So says Dicke, too: “They are confused for a while.”
But that doesn’t mean it’s effective to fight them with this. “Ants have a lot of scouts,” Boer explains. “Those go looking in all sorts of directions until they find the old scent trail again. Then, in no time, they pass on in the nest how to walk.”
‘No final solution’
Therefore, it is not possible to lock up the ants with chalk. “Even if you make a square around it. They just go over it and they find their own trail again. So this is not a final solution.”
Farmer therefore uses sidewalk chalk not to stop ants, but for research in his own backyard. “For example, I use sidewalk chalk to see what the struggles are between ants. So the territories that ants have, I mark with sidewalk chalk. They just don’t language about that. They walk all over that,” Boer said.
So what?
“In general, people try all sorts of things. It always helps only temporarily or not at all,” Boer says. Still, there are solutions, according to the ant expert. Although it does make a difference whether the ants walk inside or outside.
Indoors, it’s simple. “The best thing to do is to wash a whole trail clean so it’s completely gone,” says Dicke. You can do that very simply with soap and water. “That’s much more effective.” You can then just put the stray ants outside.
Other tips
Further, it is also preventable. “Getting rid of an ant street can be done by making sure they don’t have anything in the house at all. Make sure your food is properly cleaned up and sealed airtight. Empty your garbage can regularly,” says ant consultant Jitte Groothuis.
Thinking differently can also help. “Give them some goodies in another place. Then the scent trail inside will naturally dry up. For example, you can offer them fruit scraps at the back of the garden.”
‘Outside you can’t do anything’
Outside is a different story, according to Boer. “Outside there are so many other factors at play, there you don’t have a stable climate like in houses. It really doesn’t help there. Outside you can’t do anything.” Some people try to fight the ants there with boiling water, Boer says. But that doesn’t work either. “A lot of them die, but such an ant nest under the paving stones there are about 1,000, 2,000 ants. If you pour hot water over that, maybe 100 or 200 will die. You just have to learn to live with it, not get annoyed by it.”
By the way, the scent trail inside and outside eventually disappears on its own. As the food runs out, fewer and fewer ants use the trail and it eventually evaporates.
What is the use of the ant?
And completely without the ant, we shouldn’t want to do either. “Ants are incredibly useful animals,” says ant consultant Jitte Groothuis. “They clean up litter, for example. But they also move seeds from a lot of plants.” According to Groothuis, some seeds have so-called “ant sandwiches” on them. The ants then eat those rolls and leave the seeds behind. “That way, plants can spread.”
“Ants dig, and in the process, minerals and other nutrients are moved through the soil. But ant nests also cause the soil to be aerated. This is also very beneficial for many plants that want to grow in it.”
