Insects in summer - Firm Facts about well-known Fly Myths
Many people, who sit outside on long summer evenings in short clothing - it can hardly be more beautiful for mosquitoes. The numerous rain showers this year, according to experts, lead to an unusual number of them being around. Which tricks help and which myths persist?
Claim: Mosquitoes prefer sweet blood.
False! Mosquito expert and biologist Helge Kampen sees two errors in this statement: There is no sweet blood and mosquitoes do not orient themselves on blood but on scents. Mosquitoes react to specific scent combinations or "scent cocktails," as Kampen calls them. These cocktails, according to Kampen, consist of two components: on the one hand, the exhaled air, that is, carbon dioxide, and on the other hand, the scent given off through the skin.
According to words from an expert at the Friedrich-Loeffler-Institute (FLI), there are differences in the "attractiveness" of a person. "We have 52 mosquito species in Germany, some of which differ," says Kampen. It is quite possible that a person in a certain region is bitten by many mosquitoes, while in another region they are bitten less.
Claim: Who drinks alcohol attracts more mosquitoes.
True! If someone enjoys a beer or an Aperol on a warm summer evening, they should be aware of the effect of alcohol on their own body odor. "Alcohol causes our veins to dilate and thus increases blood flow and sweating," explains insect researcher and mosquito expert Doreen Werner. The sweat smell is then the attractant that mosquitoes react to, the biologist continues.
Several study results confirm this, for example, from the American Mosquito Control Association. The association for mosquito control had several probands drink a beer, while others remained sober. The mosquitoes were then presented with an arm of a sober person and an arm of a drunk person. The result: More mosquitoes landed on the probands who had previously drunk a beer.
Claim: Mosquitoes are attracted to light.
Almost not! Mosquito expert Kampen says that only a few mosquito species react to light. But even these mosquitoes are influenced more strongly by stimuli such as CO2 or scent substances from the skin. In addition, mosquitoes can detect the temperatures of humans at shorter distances. The closer a mosquito comes, the easier it can find a human. Therefore, anyone who runs through the apartment in the evening for safety reasons should know: "Mosquitoes also come in when the light is out," says Kampen.
The German Federal Environment Agency (UBA) writes on its website about mosquitoes that UV lamps offered for sale in the outdoor area are banned. The reason is that "mosquitoes are hardly attracted to UV light." Instead, many endangered insect species, such as certain moths, are attracted to and killed by these lamps.
Claim: Certain scent substances keep mosquitoes away.
True! However, not every repellent has the same effect. People give off different amounts of CO2 and other scents and are therefore differently attractive to mosquitoes. "One person says they can protect themselves with lavender oil, another says they have to eat garlic and the third needs the chemical weapon from the pharmacy," explains Werner. What works best for each individual can only be found out by trying.
The repellents must be properly dosed, they should reliably work and at the same time be skin-friendly, explains Biologist Kampen. The advantage of anti-mosquito products is that the used substances are standardized, thereby ensuring that their effectiveness is likely. These products, which are mainly applied to the skin, can keep mosquitoes away for several hours, Kampen explains. However, the effect eventually wears off.
Claim: Spittle soothes the itch from mosquito bites.
Partially! The itch-relieving effect is not due to the spittle itself but rather the cooling effect, explains Allergologist Mathias Sulk. Spittle is not a "cure-all," says the head of Allergology at the University Hospital Münster. With it, bacteria from the mouth mucosa can come to the skin. In the case of open mosquito bites, this is not good. Sulk therefore recommends: "I would rather give it water. It evaporates and has the same cooling effect."
In addition to cooling, specifically applied heat should also provide relief. Specially designed heat packs give off a temperature shock for a few seconds. "This heat generates a pain stimulus and this masks the itch," explains Sulk. It is important to use medical heat packs and not, for example, to heat a spoon on the stove and apply it to the bite. Then, burns can occur quickly, warns the doctor.
Whether cold or heat is better at relieving itch is mainly a subjective feeling and varies from person to person, as the allergologist says. There are no studies that have investigated which one works better. But: "We know that both works."
Claim: Mosquitoes in Germany are not as dangerous as in other countries.
True - but this is changing! Mosquitoes are generally considered the most dangerous animals in the world: Above all, through the spread of diseases such as malaria, dengue and yellow fever, "mosquitoes kill more people than any other creature on Earth," according to the US Health and Human Services Agency CDC.
People in Germany should not worry too much about this for the time being, says mosquito expert Kampen. "Mosquito-borne diseases are still quite rare in Germany." However, this could change - because both certain pathogens and mosquito species from warmer regions are thriving better here.
The Asian Tiger Mosquito, which has been occurring in Germany for a few years, is a "good vector for many dangerous viruses" like dengue and Zika virus, explains the biologist. However, there is still no known case where such a disease was transmitted from one of these mosquitoes in Germany. In southern countries like Italy, such transmissions have already occurred.
Already quite widespread in native mosquito populations in Germany is the West Nile Virus, which was first detected in Germany in 2018. According to the Robert Koch Institute (RKI), most infections in humans run symptom-free, about 20% of the infected develop a feverish, influenza-like illness, and about one in a hundred develop a brain or meningitis infection.
In Germany, six infections were reported in 2023 - however, experts assume a high number of undetected cases. The transmitting species, the Common Mosquito (Culex pipiens), is widely spread in Europe. Eliminating them is therefore not a viable way to contain the further spread of the West Nile Virus, which has mainly circulated in certain eastern German federal states.
Claim: After a harsh winter, there are fewer mosquitoes.
False! Native mosquito species are well adapted to the climate in Germany and therefore also to cold winters. The German Wildlife Foundation states on its website that mosquitoes have different overwintering strategies. Mosquito eggs take little damage from frost.
What can be problematic for mosquitoes is fluctuating weather in winter, says Kampen. Mosquitoes adjust their metabolism to temperature conditions. When temperatures rise, their metabolism is reactivated, explains the biologist. If temperatures rise and fall again, the mosquito's body reacts to this and consumes energy.
"New species, such as those that have settled here from the tropics, are of course not well adapted," says the mosquito expert. A relatively cold winter therefore harms these mosquitoes more.
- Despite the beautiful Summer evenings in short clothing, the numerous rain showers this year have led to an unusual number of mosquitoes being active.
- According to an expert at the Friedrich-Loeffler-Institut (FLI), there are differences in the "attractiveness" of a person, and it's possible that a person in a certain region may be bitten by many mosquitoes.
- If someone enjoys a beer or an Aperol on a warm summer evening, they should be aware of the effect of alcohol on their own body odor and the increased attractiveness to mosquitoes.
- Doreen Werner, an insect researcher and mosquito expert, explains that alcohol causes dilated veins, increased blood flow, and sweating, which makes the person more attractive to mosquitoes.
- The Federal Environmental Office writes on its website that UV lamps offered for sale in the outdoor area are banned due to their attractiveness to endangered insect species like certain moths.
- The repellents used to keep mosquitoes away must be properly dosed, skin-friendly, and standardized to ensure their effectiveness.
- Mathias Sulk, the head of Allergology at the University Hospital Münster, recommends giving mosquito bite victims water instead of spit due to the potential bacteria introduced from the mouth mucosa.
- Specifically applied heat can provide relief from mosquito bite itch by generating a pain stimulus that masks the itch, but it's important to use medical heat packs and avoid burning the skin.
- Mosquitoes in Germany are generally less dangerous than in other countries, but the situation may change as certain pathogens and mosquito species from warmer regions adapt to the climate here, increasing the risk of mosquito-borne diseases.
