- NZ chase 275 to win first Sri Lanka Test after Patel bags six
- Ashwin bags six wickets as India hammer Bangladesh in first Test
- Nascent French government under pressure on multiple fronts
- Angry French cognac makers see red over Chinese tariffs threat
- Protect the prosciutto: Italy battles swine fever
- UN holds 'Summit of the Future' to tackle global crises
- Marxist leader set to become Sri Lanka's next president
- From blades to pull-up bars: UK charity tackles knife crime
- Swiss vote on pensions and environment protections
- No pain, no gain: Chinese pro wrestlers fight for recognition
- UAE leader seeks to deepen 'strategic' ties in US visit during Mideast crisis
- Hezbollah takes heavy hits but still fighting Israel
- Floods, landslides hit central Japan months after major quake
- All Blacks coach Robertson demands better finishing
- Argentina edge South Africa to keep title hopes alive
- Biden says China 'testing us,' in hot mic remarks to Quad allies
- Dubois destroys Joshua to retain IBF world heavyweight crown
- Guardiola says critics want Man City wiped 'from face of the Earth'
- Biden says 'Quad' is 'here to stay' despite challenges
- Dubois knocks out Joshua to retain IBF world heavyweight crown
- Vinicius helps 'faster' Madrid overturn stubborn Espanyol
- Zelensky to press US on long-range missile strikes inside Russia
- PSG drop first points in draw at Reims
- Vinicius, Mbappe on target as Madrid crush plucky Espanyol
- Jeeno leads Ko by two at LPGA Queen City Championship
- Bottega Veneta goes for 'E.T.' chic as Madonna pops into D&G
- Messi, Miami frustrated by New York late leveler
- Musk's X platform takes first step toward lifting Brazil ban
- 'Business as usual' for Australia match-winner Carey amid boos
- Israeli jets pound Lebanon after deadly Beirut strike
- Ten Hag bemoans Man Utd's lack of killer instinct in Palace stalemate
- France's Macron appoints new government in shift to right
- Cheika proud of Leicester grit after winning start as boss
- Profligate Man Utd pay price in 0-0 draw at Palace
- Kane, Olise run riot as Bayern thump Bremen
- Diaz fires Liverpool top of Premier League, Man Utd held at Palace
- LIV champion Rahm out of LIV Team semis with severe flu
- Slot surprised by tearful Nunez's moment of magic
- Title rivals Norris, Verstappen on 'cool' front row for Singapore GP
- Biden talks China with 'Quad' leaders in hometown summit
- Juve and Napoli play out goalless draw in early Serie A title tussle
- Alcaraz fears tennis tour grind will 'kill us'
- Carey sparks recovery as Australia thrash England in 2nd ODI
- Leclerc, Sainz lament 'disappointing' Saturday in Singapore
- Bottega Veneta holds investors' aces as Madonna pops into D&G
- Beirut digs for victims at building flattened in Israeli strike
- Verstappen stages protest over 'ridiculous' swearing punishment
- Bayern boss Kompany lauds 'special talent' Olise
- Diaz fires Liverpool top of Premier League, Spurs bounce back
- Heavy fire over Israel-Lebanon border after deadly Beirut strike
Gotta bounce: Some spiders catapult away after sex to avoid death
Sometimes there are pretty valid reasons for leaving right after sex.
A team of Chinese scientists has discovered that male orb-weaving spiders fling themselves away from their partners -- pulling 20 Gs of acceleration in order to avoid being killed and eaten by females.
The mechanism, described for the first time in the journal Current Biology on Monday, involves the spiders' first pair of legs to immediately undertake a split-second catapult action.
Lead author Shichang Zhang of Hubei University in Wuhan told AFP he was "excited" to make the discovery, which required high-speed, high-resolution cameras to detect.
Zhang and colleagues were studying sexual selection in this spider, "Philoponella prominens," which live in communal groups of up to 300 individuals.
Of 155 successful matings, they found 152 ended with the male catapulting and thus surviving the encounter.
Males can mate up to six times with the same female -- bouncing off, climbing back up using a silk safety line, mating, and bouncing off again.
The three males that didn't catapult were promptly captured, killed and consumed by their partners.
Another 30 males that were prevented from catapulting by placing a fine brush behind their dorsum all met the same fate -- leading the researchers to conclude catapulting is essential to avoiding sexual cannabalism.
"Currently, I do not know whether there is any other species can also perform the catapulting," said Zhang, adding he planned to investigate further.
Sexual predation by females is seen across many spider species, with various strategies for avoiding it: male nursey web spiders, for example, tie their partners up before mating.
- A suitable mate -
The escaping orb-weaving spiders clocked some impressive statistics: their average peak speed was 65 centimeters per second, with an acceleration of 200 meters per second squared. That's equivalent to 20 Gs, or 20 times the acceleration felt during freefall.
While soaring through the air, the males spin around at some 175 revolutions per second.
The males catapult by folding the tibia-metatarsus joint of their first leg pair against females. When released, it exerts hydraulic pressure and causes the legs to expand.
Zhang said he believes the females were judging males' sexual suitability by their ability to escape.
"Through the catapulting, a male can escape female sexual cannibalism, and a female can choose males with high quality, because the kinetic performance may directly correlate with male's physical condition," he said.
Even though they have already mated, females may go on to only accept the sperm of males that passed the test, explained Zhang.
Spiders differ from mammals in that females have a structure known as spermatheca where deposited sperm is stored. They can decide whether to use it to fertilize eggs, or reject it by squeezing it out or changing the pH value to kill the sperm.
Future work will confirm whether there is a correlation between male catapulting and reproductive success, said Zhang.
Y.Bouchard--BTB