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As climate changes, lovebug swarms are likely new normal

Published: 02 Jul. 2025, 16:11

A swarm of lovebugs fly near the summit of Mount Gyeyang in Incheon on June 29. [YONHAP]

What looked like scorched earth on Mount Gyeyang last weekend was something far more alive — and far more unsettling. Swarms of mating lovebugs, their red thoraxes and black wings carpeting the trails, left hikers stunned and officials scrambling to respond.

For the past week, Kim Ju-soo, head of the forest protection team at the Gyeyang District Office in Incheon, has been fighting what he calls a “war” against the lovebug on the mountain.

The bugs, known scientifically as Plecia longiforcep and characterized by their red thoraxes and black wings, went viral on social media after videos showed them blanketing hiking trails. The posts prompted the dispatch of 10 officials to remove the insects.

This marks the fourth consecutive year of a large-scale outbreak of lovebugs in the Seoul metropolitan area, with growing public complaints. According to the Seoul Metropolitan Government, 9,296 reports were filed last year alone. Posts about sightings this year have flooded social media, particularly from areas like Mount Gyeyang in Incheon and Mount Gwanak in southern Seoul.

Officials from the forest protection team of Gyeyang District Office install insect traps and conduct disinfection as swarms of lovebugs emerge near the summit of Mount Gyeyang in Incheon on June 30. [NEWS1]

But where did they come from, and why are there so many?

A nonnative species, it was merely a decade ago when lovebugs were first discovered in Korea in Incheon. Originally found in subtropical regions below the 33rd parallel north — including southeastern China, Taiwan and Japan’s Ryukyu Islands — the insects appear to have migrated northward to the Korean Peninsula as the climate has warmed.

“An analysis of domestic specimens shows a genetic similarity to populations found in Qingdao, Shandong Province,” said Park Sun-jae, a researcher at the National Institute of Biological Resources. “They likely arrived through logistics and trade routes.”

Similar patterns have emerged in the United States. Lovebugs have expanded northward along the humid eastern corridor of the North American continent, spreading from Mexico through Texas and Florida and recently settling in Virginia, which shares a latitude with Korea.

“This recent outbreak in Korea’s capital region is the northernmost record in East Asia,” said Shin Seung-gwan, a professor of biological sciences at Seoul National University. “Whereas southern China sees two generations of lovebugs per year, the bugs now appear to be adapting to temperate climates, emerging once annually in places like Shandong and Korea.”

A giant swarm of lovebugs is seen at a trail on Mount Gyeyang in Incheon on June 28. [SCREEN CAPTURE]

Experts also say that the insect is well-suited to survival in Korea’s capital region. The rising heat and humidity, as well as the abundance of LED lighting, create favorable conditions. A 2024 report by the National Institute of Biological Resources confirmed the insects are drawn to LED light — a factor likely contributing to the outbreak.

Lovebugs are also resistant to pesticides and thrive in urban heat islands. A genetic analysis of Korean specimens by the Seoul National University team revealed traits for pesticide resistance and heat stress adaptation.

The bugs have few natural predators. While birds typically feed on insects, most avoid lovebugs due to their acidic, sticky secretions. This predator-free, favorable habitat has been linked to the scale of the outbreaks.

Though lovebugs are unlikely to transmit disease or directly harm humans, their sudden proliferation causes distress and concern. A survey by the Seoul Institute found that 86 percent of respondents considered lovebugs a pest.

Eunpyeong District officials conduct emergency disinfection for lovebugs in a residential area near Galhyeon-ro in Eunpyeong District, northern Seoul, on July 4, 2022. [NEWS1]

Still, chemical control could backfire. While some parts of North America have seen fungal pathogens infect lovebug larvae, such biological methods remain unverified in natural settings. The National Institute of Biological Resources is currently studying natural fungal insecticides as a potential solution.

“Lovebug outbreaks typically subside after about two weeks,” said an environmental official. “Given the uncertainty around the ecological effects of chemical controls, the best approach for now is physical removal — such as spraying water.”

Translated from the JoongAng Ilbo using generative AI and edited by Korea JoongAng Daily staff.
BY JEONG EUN-HYE, CHON KWON-PIL [[email protected]]