13 Unique Australian Animals

They’re closely related – the US spider is Latrodectus mactans, the redback is Latrodectus hasselti – however it appears that L. mactans has been redefined several times with other species together or separate, currently they are separate. There are several related species on Pacific islands and New Zealand, I’d love to know how well these have been studied and if they could be the same.

They weren’t recorded until 1870, which is quite late if they were as common as they are today, and were found in Queensland seaports. Plus Qld and the NT have a long history of contact with other islands, particularly Indonesia, so they could have come in on sailing ships or with non-Europeans, like dingoes and cats. (Cats have been introduced twice.)

The lack of Dreaming stories is interesting but complicated. We’ve lost so many stories, and a lot that are still around cannot be recorded because they are secret, sacred knowledge. But it would be unusual if that included all stories about redbacks. Also many Aboriginal people have a very dry sense of humour. I know of at least one person who came to a community to ‘record their stories’ and was fed a pile of BS. So our knowledge of Dreaming stories is pretty spotty and inaccurate. There are some Aboriginal sounding names for the redback – Murra-ngura spider, Kapara spider and the Kanna-jeri spider – but they could be new names or misunderstandings of Aboriginal words.

Looking further afield, accidentally introduced species that do well generally spread to other countries too. There is a small colony of redbacks in NZ and some in Japan. In NZ they could be contained by the native species, but in Japan they have no competitors and you would expect them to spread very quickly, which they don’t appear to have done. So they aren’t really acting like a typical introduced species.

And just because a species does well out of invasion doesn’t mean it isn’t native – galahs are a classic example. European agriculture has allowed them to drastically increase their numbers and range, but they’re most definitely native! So redbacks could have been a small part of the bush ecosystem, as they are today, but adapted very well to urban settings.

It sounds like it’s a definite maybe 🙂 There are arguments both ways, it would be fascinating to test them genetically but I don’t think that will happen soon. They have definitely spread and increased thanks to European settlement, but it could have been as a native or immigrant. Thanks for a fascinating little research project.