- New York drought conditions fan flames, spur water saving
- Football 'world order' is changing, says Brazil coach
- Maiden century by Varma gives India unbeatable series lead
- Buy now, pay later: Latin America pressured by Chinese online shops
- Republicans complete power takeover with House majority
- Kane disappointed by England Nations League withdrawals
- Trump victory signals golden era for crypto industry
- 'First Buddy': Musk takes unusual star role with Trump
- Workers stage walkout at US maker of Fallout video game
- England will not change 'DNA' against South Africa, says Slade
- Biden, Xi to meet in Peru on Saturday: US official
- Spurs coach Popovich suffered 'mild stroke', says NBA team
- 'Very humiliating': Bangladesh's Yunus seethes over climate cash fight
- 'Welcome back': Trump, Biden shake hands in White House
- Tech's green wave hits choppy waters
- Fernandes hopes Amorim can 'change the energy' at Man Utd
- Trump, Biden shake hands in White House, vow smooth transfer
- Gatland battling 'pain' during tough Wales rebuild
- COP29 fight for climate money 'humiliating': Bangladesh's Yunus
- McIlroy aims for glory on happy hunting ground in Dubai
- Spain evacuates thousands in fresh flood alarm
- US death row inmate stages jazz protest for release in London court
- Germany's embattled Scholz trades blows with rivals as election looms
- Alcaraz beats Rublev to open ATP Finals account
- 'I had to gather my strength': Ukrainians abroad sign up to fight
- 'Legend' Healy set to equal O'Driscoll record against Pumas
- Record stand propels Sri Lanka to 324-5 against New Zealand
- US consumer inflation rises in October on higher housing costs
- S.Africa football chief arrested on fraud, theft charges
- UK's The Guardian stops posting on 'toxic media platform' X
- Berlin's creatives rally against arts funding cuts
- Barca's Fati sidelined with hamstring injury
- Heavy rains lash Spain after deadly floods
- India delivery app Swiggy shares gain on market debut
- Performance not results counts for Pumas coach Contepomi
- No end in sight to Sudan war as both sides seek 'decisive' win
- Demands for Church of England reform after abuse scandal
- Russia launches drone, missile barrage on Kyiv
- Iran hangs man 'for second time' after previous execution halted: NGO
- US vows 'firm' response to N.Korea deployment in Ukraine conflict
- Airlines ground Bali flights after volcano erupts
- Indonesians drill for disaster before tsunami anniversary
- Journalist says his detention removed Guatemala's 'mask of democracy'
- Triumphant Trump returns to White House to meet Biden
- Nearly half of tropical coral species face extinction: report
- Stark warning on emissions as leaders split on climate goals at COP29
- Istanbul's historic baths keep hammam tradition alive
- Australia boss warns of 'desperate' Saudis in World Cup qualifier
- South Korean president dusts off the golf clubs for Trump
- Electrician finds frescoes behind false ceiling in Rome
CMSC | 0.28% | 24.61 | $ | |
CMSD | 0% | 24.75 | $ | |
JRI | 0.05% | 13.227 | $ | |
SCS | -2.28% | 13.365 | $ | |
BCC | 1.07% | 142.65 | $ | |
BCE | -1.65% | 27.24 | $ | |
RYCEF | -0.7% | 7.11 | $ | |
RBGPF | -1.43% | 59.34 | $ | |
RIO | -0.84% | 60.692 | $ | |
NGG | -1.35% | 62.065 | $ | |
GSK | -1.07% | 35.145 | $ | |
BTI | 0.47% | 35.408 | $ | |
BP | 1.4% | 28.56 | $ | |
RELX | -0.98% | 46.138 | $ | |
AZN | 0.18% | 65.31 | $ | |
VOD | 3.31% | 8.76 | $ |
Some male 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.
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.
The escaping 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. She can decide whether to use it to fertilize her 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.
J.Pereira--PC