Ministry warns of illegal insect traps

Horsefly traps are quite popular in gardens – especially in the Berlin area near the many paddocks. But they mainly kill other insects.

A horsefly trap in a paddockImago Images

The currently damp weather causes many puddles and pools of water. Ideal breeding grounds for many insects. And when spring really gets going after the rainy April weather this time, they are back: the mosquitoes. And later also wasps and horseflies. All those flying and stinging insects that many city dwellers often only perceive as annoying pests and fight against them.

So-called horsefly traps have become increasingly popular for some time. Because they are mainly set up near horse paddocks, of which there are plenty in Berlin, but even more in the Berlin area. Because horseflies like to bite horses and cattle to feed on their blood.

The Potsdam Ministry of the Environment is now calling for the horsefly traps to be dispensed with. Their use could even be against the law. The main reason: The traps are primarily used to catch other insects that are important for preserving biodiversity.

The great insect extinction

According to the ministry, many people set the traps as early as the spring. “Although the main flight time of horseflies is between the beginning of June and mid-September,” the ministry said. “However, this kills numerous insects of various species in these traps in spring, including protected wild bees and butterflies.”

And that in turn is a big problem, because with the increasing industrialization of agriculture, the use of pesticides such as glyphosate and the drought caused by climate change, the largest insect die-off in a very long time has been taking place for years. In Germany, the so-called Krefeld study from 2017 is used as evidence: The Krefeld Entomological Association had compiled data on 63 German protected areas with the result: between 1989 and 2016 a decline in the biomass of flying insects of 76 percent was found.

Many ask themselves: Why are there mosquitoes, wasps and horseflies at all? What are their uses? Basically, animals and plants just exist and don’t have to be of any use to humans. But they still have it: bees and many other insects pollinate flowers and most other plants. Without insects, people would have no or much less and much more expensive food from the field.

In addition, most insects or their larvae are the food base for many other insects, birds, fish and amphibians. They are part of the great food chain. And with the decline in insect populations comes a noticeable decline in certain bird species.

Very few mosquitoes bite

In addition, even mosquitoes are much better than their reputation. Experts like Doreen Werner from the Leibnitz Center for Agricultural Landscape Research in Müncheberg, east of Berlin, point out that there are 28 species of mosquitoes in Germany, and the mosquito is just one of them.

Insects are important to humans and should be left as undisturbed as possible. The Brandenburg Environment Ministry also points out that horsefly traps are not particularly effective. Basically, they work according to a simple principle: A round black ball with a net above it hangs on a rope. The idea behind this: horseflies only see very blurred, and the round ball, which heats up in the sun and moves back and forth on the rope, is supposed to simulate a horse’s hindquarters for the insects. They fly at the “prey” from below, and when they realize that it’s not a horse, they want to turn upwards, but get caught in a net there and fall into a funnel.

The problem with this: “This trap catches numerous useful insects – but horseflies hardly end up in it,” says the ministry. It refers to a study from North Rhine-Westphalia. Seven horsefly traps were set up there from May to October. A total of 53,400 insects were caught. The proportion of horseflies was only four percent, the rest were other insects, including wild bees, beetles and butterflies, including legally protected or endangered species. The ministry therefore emphasizes: “Without a special permit under species protection law, horsefly traps can therefore violate the Federal Nature Conservation Act.” Therefore, the use of horsefly traps should be avoided altogether.