People who go on bushwalks with me are often surprised at how many insects I find. It’s all about the ‘search image’. It’s like Tom Sawyer’s idea of throwing a second marble away to find the first – developing a ‘search image’, but perhaps risky as far as marbles go. Images of insects are indelibly stuck in my head and so that’s what I find. On the other hand, I often don’t notice what I’ve eaten for dinner or what clothes people are wearing and an artist once told me I don’t observe much. It depends on what you want to see.
Going out in the bush with colleagues, with their own search images, often reveals things that I miss. Recently the museum was visited by a spider expert, working on funnel-webs, not something I usually see. He wanted to obtain some specimens for molecular analysis, so I took him to a few of my local haunts and within 10 minutes he had four funnel-webs by the road at the Wilsons Creek waterfall, Helensburgh. These are the Sydney funnel-webs (Atrax species), whose males can kill (13 deaths in total). We found a few more at Otford and in his estimation they are common in wetter forest patches throughout the Illawarra. Certainly we have friends in Stanwell Park who have them in the back garden.
They are not just under logs but also stones, and the males wander around to find females, which is why people tend to come into contact with males rather than females. Females are not dangerous.
My German colleague’s interest in the Sydney funnel-web was piqued by finding that there is quite a bit of variation in the size and shape of the males, suggesting more than one species. This immediately raised a problem to me – are people milking the wrong sort of spider for antivenom? But I was assured that all of this group of spiders use the same venom, just different concentrations of it.
The scientific name, Atrax robustus, was coined 150 years ago by the splendidly named Reverend Octavius Pickard-Cambridge. He was the leading spider taxonomist of his day, describing more than 900 species, while administering to his flock (of humans) in Dorset. Unusually, for a Victorian cleric, he was a supporter of Darwin.
There are several different sorts of large black spiders (body length 1-5cm) in the Sydney area. The Sydney funnel-web has a smooth shiny flat cephalothorax (front half of body) with a deep curved groove on it, large downward curved jaws and four spinnerets at the end of the abdomen (but the outer pair are small). The male has a cephalothorax larger than its abdomen and long legs with a large ventral projection on the second pair. But you may not want to get that close to see.
If someone is bitten, treat like a snake bite – use a pressure bandage, keep them still, and get an ambulance immediately. Keeping the specimen (even squashed) will help to diagnose the spider.
Our own Symbio Wildlife Park has a spider milking programme.
The Australian Museum has an excellent website on these and other spiders here.
For general insect enquiries, visit australianmuseum.net.au/learn/species-identification/
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