Tropical trap-jaw ants spreading across Japan's Honshu island

December 07, 2012


Trap-jaw ants, normally found in tropical and subtropical regions, have spread on the main Japanese island of Honshu, including such heavily populated areas as Tokyo, Kanagawa and Osaka prefectures.

Global warming may have created a favorable environment in Japan for the ants, which have huge, powerful jaws and a venomous stinger at the end of their abdomen, said entomologist Mamoru Terayama, a lecturer at the University of Tokyo.

“We have to examine their impact on ecosystems,” he said.

Winged ants with large jaws have been found in Kanazawa-shizenkohen park in Yokohama, Kanagawa Prefecture, since 2010.

In July this year, a worker at the Kanazawa Zoo in the park discovered the insects building a nest. Terayama identified them as trap-jaw ants.

They were also spotted this year in Musashimurayama in Tokyo, Mino in Osaka Prefecture, Akaiwa in Okayama Prefecture, and Inabe in Mie Prefecture, Terayama said.

The ants live primarily in Southeast Asia, but they also have been recognized on Yakushima island, Tanegashima island and other parts of southern Kyushu.

The trap-jaw ant is a large ant of 10 to 13 millimeter in length. Its mandibles can open to a 180 degree angle.

The jaws snap shut at such high speeds that the force created can propel the ants in the air backward to escape a predator.

“(The recently found ants) are very likely to be an alien species,” Terayama said. “The queen ants may have immigrated in potted plants.”

  • 1
submit to reddit
Trap-jaw ants (Photo by Kazuhiro Itami)

Trap-jaw ants (Photo by Kazuhiro Itami)

  • Trap-jaw ants (Photo by Kazuhiro Itami)

More AJW