Many male spiders engage in聽courtship rituals during mating, but some attack females instead and tie them up to avoid being eaten.
鈥淪piders sometimes spend hours luring females to court them, but these guys just go and bite,鈥� says Lenka Sentensk谩 at the University of Toronto Scarborough, Canada.
Running crab spiders, a group containing more than 600 species, are found widely across Europe, Asia and Africa.聽In April 2019, while working at Masaryk University in Brno, Czech Republic, Sentensk谩 was studying the behaviour of one species 鈥� Thanatus fabricii 鈥� that is native to Israel. She realised males behaved oddly at mating time, but the action was so quick that it was difficult to observe.
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Sentensk谩 and her colleagues chased down a number of the fast-moving spiders in the Negev desert in Israel and brought them to the lab for closer observation.聽Slow-motion recordings gave the researchers a clearer look at the reproduction of these spiders.
鈥淭he male just rushed towards the female and it seemed more like an attack,鈥� says Sentensk谩. The male spider would bite the female a handful of times, more so if she was larger and less so if she was missing limbs.
In most cases, this seemed to startle the female spider, who would pull in her legs and play dead. At this point, the male spider would begin to lay down some strands of silk on the female鈥檚 body, binding her legs. The male spider then mated with the female for the next 19 minutes, on average, before running away.
The behaviour is savage, but it may be the best way for males to come out of the mating process alive. The team observed that some males were eaten by the slightly larger females before they could begin biting.
Even when tied up, the female spiders may be in control. Sentensk谩 says it doesn鈥檛 take a female spider long to break free. 鈥淪he would jerk several times, then spread her legs and she鈥檚 good to go.鈥�
Sentensk谩 speculates that the silk binding may contain a chemical message about the male spider鈥檚 suitability. If he is to her liking, a female spider may decide to let the male continue mating for longer before breaking free.
鈥淚t appears brutal, that the female has no choice, but that鈥檚 probably not how it is,鈥� she says.
Animal Behaviour
