Problem Statement: In September 1995, a previously unrecorded spider was found in Osaka, Japan. The spider closely resembled the Red Back spider from Australia, one of the notorious and highly poisonous “black widow” species. However, Osaka lies several thousand kilometres away from Australia across the Pacific Ocean and has a much colder climate. Were these really Red Back spiders, surviving a long way north of their usual haunts?

Methods: Taxonomic information on spiders is freely available via the World Spider Catalogue. Informal networks of spider specialists such as the International Society of Arachnology, ISA also exist and all known species of spiders have been catalogued since the 1950s. In Australia, particular efforts were made to make taxonomic information on spiders readily accessible and a CD-ROM on ‘Spiders of Australia’ was published in 2002. With the help of these resources, spider specialists and identification keys, it was possible to verify that the new spider in Japan was the Australian Red Back or Black Widow.

Outcomes and Impacts: The arrival and persistence of the tropical Australian Red Back spider in Japan is highly significant for other countries with temperate climates, indicating that they are not safe from the introduction of tropical, poisonous spiders and adequate preventive measures need to be taken. As climate change pushes temperate climatic zones further towards the poles, such threats will continue to grow. The Australian Red Back is much more resistant to cold than previously believed. In Japan, they survive temperatures below freezing for periods of several days without ill effects and even reach higher population densities than in Australia.

Lessons: Sound taxonomic knowledge combined with freely accessible taxonomic information on spiders and a worldwide network of experts proved essential for swiftly identifying the poisonous spider and developing focused and efficient measures for pest management and public education.