The male factor
Rearing Hadronyche versuta. Note venom on fangs. Photo: M Gray © Australian Museum.
Male Sydney Funnel-web Spiders have been responsible for all recorded funnel-web envenomation deaths - why is it so? The answer lies in a combination of spider behaviour, venom chemistry, and even colonial politics.
- During the warmer months of the year (November-April) male funnel-webs wander about at night looking for females in their burrows
- Males wandering in suburban gardens may sometimes become trapped inside houses or garages, especially those with concrete slab foundations where entry points under doors are easily reached
- The venom of the male Sydney Funnel-web Spider is very toxic. This is because male spider venom contains a unique component called Robustoxin (d-Atracotoxin-Ar1) that severely and similarly affects the nervous systems of humans and monkeys, but not of other mammals (a difficulty for 'creation science' which believe in a special creation for humanity). The absence of this chemical from female Sydney Funnel-web Spider venom explains why bites by these females have not caused any deaths. However, not all funnel-web species show such a large gender-based difference in venom toxicity
- Almost four million people live in the Sydney region, the centre of the distribution of the Sydney Funnel-web Spider. This makes the likelihood of human encounters with this spider much greater than in less urbanised areas like the Blue Mountains. This situation, of course, stems from a political decision made in London more than 220 years ago, to establish a colony in 'New South Wales' at Sydney Cove, a site nominated by Captain James Cook after his voyage of exploration.
Taken together, these ingredients produce a recipe for unexpected and potentially life-threatening encounters.
