March 2005. An article from the New Zealand Herald regarding the redback spider in Auckland. It is now established in New Zealand and Tonga was concerned about it spreading there. Reassurances were needed that they cannot survive in high temperatures, high humidity, lowland tropical conditions. The article concerned redbacks in the wheel arch of a vehicle that had passed inspection.
Redbacks are pretty adaptable spiders, found all over Australia, although they do prefer drier areas. However those drier spots are generally within moister regions – e.g., they are pretty common around Sydney and Brisbane, which are also high temperature, high humidity, places. They pose a significant detection problem, because they like dark hidden places.
There are many excellent websites about them with links to others of interest e.g.: www.ento.csiro.au/insect_id/spiders/redback_spider.html and www.austmus.gov.au/factsheets/redback.htm. Some informtion from the Australian Museum website was provided.
There was also a report that they have beome establsihed in Japan. Redbacks are also present in Lord Howe Island, Argentina and Belgium. A problem in Japan is that native spiders are not dangerious to humans. However, of more concern is the brown widow spider, Latrodectus geometricaus. This species is a native of the USA and has become established in Darwin and probably elsewhere in Austalia. It is also commonly intercepted in quarantine from Indonesia and south-east Asia.
This species is similar to the redback, but has geometric marks on the abdomen and is usually slightly paler. Its egg sacs are similar, but have a series of small lumps on them. These lumps are distinctive and obvious.
This species is as venomous as the redback and black widow spider and has become a tramp species that readily establishes itself in new countries.