An outbreak of lovebugs, a species of March fly that remains in pairs, has spread rapidly to areas across Seoul over the weekend, according to reports from authorities Sunday.

In 2022, several complaints were filed about lovebugs in northwestern Seoul and Goyang, Gyeonggi Province. However, this year, the outbreak has spread to other districts, such as Dongdaemun-gu and Seongdong-gu in eastern Seoul, and Gwanak-gu in southern Seoul, authorities said.

Lovebugs aren’t toxic or harmful, but they have become a nuisance following invasions of residential areas and local shops, where they tend to stick to clothing and vehicles.

Yang, an office worker who lives in Eunpyeong-gu, one of the worst-hit districts in Seoul said, “I like to open my windows at least once a day to bring in fresh air. But I can’t do that anymore because I’m worried that they’ll fly into my house.”

Though the reason behind the outbreak has not yet been confirmed, professor Shin Seung-gwan from Seoul National University’s School of Biological Sciences predicts that the insects have spread through what he calls the “hitchhiking method.”

“Lovebugs may have spread around Seoul by flying to other districts, or 'hitchhiking' by sticking onto cars or subway trains,” said professor Shin in an interview with Yonhap News Agency.

There are increasing complaints by citizens asking their respective municipalities to spray pesticides in areas infested by lovebugs. However, experts like Shin say that such an approach isn’t ideal, as it “can kill other bugs that eat lovebugs, leading to bigger insect outbreaks.”

Instead of continuously spraying pesticides or disinfectants, local governments are taking a more careful approach. Eunpyeong-gu Office, for example, is distributing handouts to their residents explaining how they can kill the bugs on a smaller scale, such as spraying them with water. Experts also recommend using flypaper to prevent the bugs from getting inside the house.