Although many people tremble and even scream at the sight of spiders, we have little or no news of who was killed by spiders. But in Australia, there is really a spider that can kill people, once bitten by it, if it is not injected with detoxification serum in time, it may die in a few hours or even tens of minutes, and the most terrible thing is that a child is bitten and dies within 15 minutes.
This spider is the Sydney funnel web spider and only lives within 100 kilometers of Sydney. The spider is about 1 to 5 centimeters long, but there have been larger appearances, with the largest leg ever seen up to 10 centimeters long. Sydney funnel web spiders are similar in morphology, with males slightly smaller than females but longer legs. The Guinness Book of World Records lists the Sydney Funnel Web Spider and the Brazilian Stray Spider as the most poisonous spider in the world, and emphasizes it as "the most toxic venom to humans".
According to documented cases, the Sydney funnel web spider has killed a total of 13 people, but since the development of the antivenom in 1981, there have been no more deaths. However, being bitten by the spider is still extremely painful, resulting in massive saliva production, muscle twitches and difficulty breathing, confusion in direction and loss of consciousness. The treatment process was also extremely difficult, in February 2017, a 10-year-old boy was bitten by a spider hidden in a shoe, and it took 12 bottles of antivenom to retrieve one life, usually two bottles, sometimes four bottles.
So why is the Sydney funnel web spider so vicious? Humans, in particular, are not their prey, and their venom is extremely deadly to humans and other primates, and scientists have long studied it. On 21 September, Bryan Fry, associate professor at the University of Queensland's School of Biological Sciences, and Volker Herzig, associate professor at Sunshine Coast University, published a paper revealing the secret behind Sydney's funnel web spider injuries.
Researchers believe that the Sydney funnel web spider's ability to kill human venom is just an evolutionary coincidence and not specifically designed to deal with us. The toxicity of spider venom is different between male and female, and it is staged, the toxicity of female spiders can not cause death, and the male spiders before adulthood are not toxic enough to kill humans, and only adult spiders will pose a huge threat to humans.
The reason why male funnel web spiders develop highly toxic and rapidly effective venom in adulthood is because female spiders spend their entire lives in their burrows, and male spiders must travel a long way to find them to pass on, and on the way, they will inevitably encounter the tragedy of being eaten by insects, birds, reptiles, etc., so they have evolved strong toxicity to protect themselves.
According to scientists' genetic sequence tracking of the Sydney funnel web spider toxin δ-hexatoxins, millions of years ago its toxin could only deal with insect predators such as cockroaches and flies, and over time, the venom of adult male spiders evolved to deal with vertebrate predators who wanted to eat it.
So humans are bitten by Sydney funnel web spiders, most of them occur in the mating season of summer people, understand, this time less out of the house is good, after all, everything can be bad, other people's good things must not be broken.
论文：Australian funnel-web spiders evolved human-lethal δ-hexatoxins for defense against vertebrate predators