Following the 'Pararak' Light, a Dark Swarm Attacks... Dayfly 'Alert' Spreads to Gangnam

Recently, swarms of mayflies have appeared under the lights in Seoul, causing inconvenience to citizens.

These are 'Dongyang Harusari' (Oriental mayflies), measuring 3cm in body length and nearly 5cm when their wings are spread. According to local governments in Seoul and Gyeonggi Province on the 19th, Dongyang Harusari have been appearing intensively since May. They are mainly observed in Seoul's Gangdong, Gangnam, Gwangjin, Songpa, Seongdong districts, as well as in Yangpyeong, Namyangju, and Hanam in Gyeonggi Province.

Oriental Mayfly
Photo by Namyangju City

Dongyang Harusari are not sanitary pests. However, due to their habit of being attracted to bright lights, they gather intensively around lights, causing discomfort and inconvenience in daily life.

On the 18th, Dongyang Harusari were even captured on the broadcast screen during a baseball game at Jamsil Baseball Stadium in Seoul. At that time, so many mayflies were observed in the stadium that players had to swat them away with their hands while playing.

Dongyang Harusari inhabit clean waters such as second-grade or higher rivers, and since their mouths are degenerated, they do not bite or transmit infectious diseases. They generally die naturally within 4 to 5 days, but since the Han River basin, their larval habitat, is a water source protection area, spraying insecticides and disinfection are difficult.

On the afternoon of May 13, 2022, during the KBO League game between the KIA Tigers and LG Twins at Seoul Jamsil Baseball Stadium, mayflies were flying in the sky above.
[Photo by Yonhap News]

They have a characteristic attraction to bright lights, so they gather intensively around streetlights or shop lights. When their wings are spread, they reach a size of 5cm and are sometimes called 'Tinkerbell.'

They are usually known to be active from mid to late May, but this year, the appearance period has come earlier due to the rise in temperature earlier than usual.

As a result, convenience stores and regular restaurants have sighed over the damage to their business, and citizens have expressed discomfort.

Oriental mayfly stuck on the convenience store window
[Photo by Namyangju City]

Accordingly, local governments are also considering countermeasures. On the 16th, Gwangjin-gu announced that it would operate 44 additional 'sanitary pest insecticides' mainly in residential areas, parks, and along the Han River, where insects are likely to appear.

In Seongdong-gu, where Dongyang Harusari have concentrated every year, the district office provided guidance on pest control methods. Seongdong-gu Office said, “Since Dongyang Harusari are attracted to bright lights, please minimize lighting brightness after 8 p.m., and if unavoidable, use yellow-toned lights or sodium lamps.”

How to Deal with Oriental Mayflies
[Image Source=Seongdong-gu Office Blog]

This content was produced with the assistance of AI translation services.