Sexual cannibalism: Male orb-weaving spiders catapult off females to flee loss of life

For the primary time, spiders have been noticed escaping sexual cannibalism by flinging themselves away from females, reaching speeds of as much as 88.2 centimetres per second


25 April 2022

To escape sexual cannibalism, some animals transfer stealthily to keep away from detection and even play lifeless – however male orb-weaving spiders have developed one other method: after copulation, they quickly catapult to security. This is the primary time catapulting to keep away from being eaten by a mate has been reported.

Shichang Zhang at Hubei University in China and his crew first observed this behaviour whereas learning orb-weaving spiders within the mountains in Wuhan in October 2019.

The researchers determined to analyze issues additional within the lab. They used high-speed cameras to seize the behaviour of 155 mating pairs of an orb-weaving spider (Philoponella prominens). Only three of the males didn’t catapult after mating, and all have been promptly captured, killed and eaten by their companions. All of the males that catapulted after mating survived.

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Copyright: CREDIT: Shichang Zhang

Shichang Zhang

To additional take a look at the need of this behaviour, the researchers put a small paintbrush behind the spiders that blocked the males from catapulting. They, too, have been all killed and eaten.

The cameras revealed that the males launch themselves at exceptional speeds of as much as 88.2 centimetres per second, which Zhang says is spectacular for a spider solely round 3 millimetres in size. That is as if an individual 183 centimetres tall flung themselves 538 metres – the size of about 5 soccer fields – in 1 second.

William Brown on the State University of New York at Fredonia says this analysis contributes to our understanding of how sexually cannibalistic species proceed to efficiently mate. But he wonders if the escape technique may additionally be utilized in response to different threats. “Have males co-opted a general anti-predator defence or is this uniquely an adaptation to reduce the risk of sexual cannibalism?”

Zhang and colleagues hypothesise that this behaviour developed to sign health as mates. “If a male could not catapult, or the catapulting ability is not good, the female may deplete or eliminate its sperm, and accept other males’ courtship and sperm,” says Zhang.

Journal reference: Current Biology, DOI: 10.1016/j.cub.2022.03.051

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