A male spider catapulting off a woman throughout mating.
These male spiders catapult at remarkable speeds to flee their mates before they get consumed.
After males of the orb-weaving spider Philoponella prominens mate with a woman, they quickly release themselves away, researchers report today (April 25, 2022) in the journal Current Biology. Utilizing a system that had not been explained prior to, the male spiders utilize a joint in their first pair of legs to right away undertake a split-second catapult action, flinging themselves away from their partners at outstanding speeds clocked at up to 88 centimeters per 2nd (cm/s).
” We discovered that mating was constantly ended by a catapulting, which is so quickly that common cams could not tape-record the details clearly,” says Shichang Zhang of Hubei University in Wuhan, China.
The reason the males catapult themselves is easy: to prevent being eaten by the woman in an act of sexual cannibalism. The couple of males the scientists saw that didnt catapult were immediately caught, eliminated, and taken in by their female partners. When the scientists prevented males from catapulting, they fulfilled the exact same fate.
All those catapulting males endured their sexual encounters.
The males manage to catapult at these speeds by folding their tibia-metatarsus joint against the female.
The factor the males catapult themselves is basic: to avoid being consumed by the woman in an act of sexual cannibalism. The couple of males the researchers saw that didnt catapult were quickly captured, eliminated, and taken in by their female partners. When the researchers avoided males from catapulting, they met the very same fate.
This photograph reveals two Philoponella prominens spiders breeding. Credit: Shichang Zhang
Zhang and associates made this discovery while studying sexual choice in this spider, which lives in common groups of approximately 300 people in a web complex with numerous individual webs within it. Of 155 effective matings, they report that 152 ended with the male catapulting. All those catapulting males endured their sexual encounters.
The 3 males that didnt catapult were eliminated. Another 30 avoided by the scientists from catapulting likewise got killed and eaten by the female. The researchers say that the findings reveal clearly that the catapulting behavior is needed to avoid sexual cannibalism.
This video shows a male spider catapulting off a female during mating. Credit: Shichang Zhang
With high-resolution camera, the scientists determined an average peak speed of catapulting spiders of about 65 cm/s. Speeds ranged from about 30 cm/s to almost 90 cm/s. They likewise sped up at an average of about 200 m/s2. As they soar through the air, the males also spin around 175 times per second on average.
The males manage to catapult at these speeds by folding their tibia-metatarsus joint versus the woman. When launched, hydraulic pressure enables fast growth. The joint in question lacks extensor muscles in spiders, they describe.
This photograph shows 2 Philoponella prominens spiders breeding. Credit: Shichang Zhang
” We observed that males that might not carry out the catapulting were cannibalized by the woman,” Zhang says. “It suggests that this habits developed to fight against females sexual cannibalism under strong predation pressure of women.
” Females might use this habits to evaluate the quality of a male during mating,” he includes. “If a male could not carry out catapulting, then kill it, and if a male might perform it several times, then accept its sperm.”
In future research studies, they wish to check out the role of catapulting capability in male mating success.
Reference: “Male spiders avoid sexual cannibalism with a catapult system” by Shichang Zhang, Yangjié Liu, Yubing Ma, Hao Wang, Yao Zhao, Matjaž Kuntner and Daiqin Li, 25 April 2022, Current Biology.DOI: 10.1016/ j.cub.2022.03.051.
This work was supported by the grants from the National Natural Science Foundation of China, the Ministry of Education AcRF grants from Singapore, and the Slovenian Research Agency.