SAPPORO - Japan's northernmost main island of Hokkaido, long known for its reputation as being largely cockroach free, may begin to see more of the insects as factors including warmer temperatures spurred by climate change create ideal environments for cockroaches to thrive.
Experts are already urging people to brace for an influx in cities including Sapporo amid increases in the number of well-insulated homes and shipments from warmer areas in Japan, which are thought to contribute to the trend.
Despite the widely held belief, Hokkaido has been home to some species of the pests, especially those more resilient to colder climates.
"Their numbers are definitely lower compared to (the main island of) Honshu," said Hiroshi Nishino, assistant professor at Hokkaido University. "They have also gone unnoticed due to being nocturnal and difficult to spot."
While cockroaches are common in subtropical climates, those seen in Hokkaido are largely made up of three species including the Japanese cockroach, which is said to have existed on the northern island for over 100 years.
According to Shizuma Yanagisawa, deputy director of Ryuyo Insect Nature Observation Park in Shizuoka Prefecture and self-appointed "cockroachist," advanced heating systems and well-insulated homes have provided warm habitats through the winter for species that are more sensitive to cooler temperatures.
The rapid increase in online shopping and shipments from Honshu and areas farther south may also have brought cockroach eggs onto the island.
Sales of anti-cockroach products have risen in response. According to major Japanese pharmaceutical company Earth Corp., its insect repellant line has grown in Hokkaido, with those catering to cockroaches climbing by about six percent on average per year between 2017 and 2025.
"It is important to create an environment that discourages cockroaches such as not leaving food or dishes out for long periods of time, cleaning thoroughly and not hoarding objects in cardboard boxes," said Akihiro Kitaguchi from the marketing department of the company.
