Flatworms that make sex their weapon

HERMAPHRODITE marine flatworms bury their feminine side and behave in the most crude, macho fashion when it comes to mating, indulging in swordplay with their penises. And female oystercatchersare frequently seen to indulge in lesbian copulation when they share a male. These new observations are in the latest edition of Nature.

The flatworms have a full set of female and male equipment, but it turns out that they all want to be the impregnator and penetrator. The only way of resolving who gets to play the male is by duel. Flatworms go sharp-tipped penis to penis; the loser is the first to be impaled, receiving sperm by hypodermic injection from its fencing partner. The mating ritual of Pseudoceros bifurcus was discovered by German researchers. Australian scientists watched duels among 17 pairs of the worms.

At Groningen University, in the Netherlands, researchers have been studying oystercatchers, normally monogamous, although 3 per cent of females share a male. Half of these love triangles involve ''highly aggressive'' relations between the females. But in the other half they share one nest and the male harmoniously, defend their territory against other oystercatchers and copulate regularly with each other and the male.

Start your day with The Independent, sign up for daily news emails
Have you tried new the Independent Digital Edition apps?
ebooks
ebooksAn introduction to the ground rules of British democracy
Arts and Entertainment
Lionel Richie has made the top spot after a strong Glastonbury performance
musicAnd what's more it's the last Sunday night chart topper - ever!
News
news
Life and Style
The collection displayed Versace’s softer side, with models wearing flowers and chiffon dresses in unusual colourings
fashionVersace haute couture review
Arts and Entertainment
DJ Chris Moyles who claimed to be a second-hand car dealer in a bid to save up to £1 million in tax, a tribunal has found
radio
Arts and Entertainment
'The Leaf'
artYes, it's a leaf, but a potentially very expensive one
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Recruitment Genius: Home Care / Support Workers

£7 - £10 per hour: Recruitment Genius: This care provider is looking for Home ...

Recruitment Genius: Web Team Leader

£30000 - £35000 per annum: Recruitment Genius: One of the UK's leading web des...

Recruitment Genius: Client Manager

£27000 - £35000 per annum: Recruitment Genius: A growing, successful, friendly...

Recruitment Genius: Property Negotiator - OTE £20,000+

£16000 - £25000 per annum: Recruitment Genius: This family owned, independent ...

Day In a Page

Greece says 'No': A night of huge celebrations in Athens as voters decisively back Tsipras and his anti-austerity stance in historic referendum

Greece referendum

Greeks say 'No' to austerity and plunge Europe into crisis
Ten years after the 7/7 terror attacks, is Britain an altered state?

7/7 bombings anniversary

Ten years after the terror attacks, is Britain an altered state?
Beautiful evening dresses are some of the loveliest Donatella has created

Versace haute couture review

Beautiful evening dresses are some of the loveliest Donatella has ever created
No hope and no jobs, so Gaza's young risk their lives, climb the fence and run for it

No hope and no jobs in Gaza

So the young risk their lives and run for it
Fashion apps: Retailers roll together shopping and social networking for mobile customers

Fashion apps

Retailers roll together shopping and social networking for mobile customers
The Greek referendum exposes a gaping hole at the heart of the European Union – its distinct lack of any genuine popular legitimacy

Gaping hole at the heart of the European Union

Treatment of Greece has shown up a lack of genuine legitimacy
Number of young homeless in Britain 'more than three times the official figures'

'Everything changed when I went to the hostel'

Number of young homeless people in Britain is 'more than three times the official figures'
Compton Cricket Club

Compton Cricket Club

Portraits of LA cricketers from notorious suburb to be displayed in London
London now the global money-laundering centre for the drug trade, says crime expert

Wlecome to London, drug money-laundering centre for the world

'Mexico is its heart and London is its head'
The Buddhist temple minutes from Centre Court that helps a winner keep on winning

The Buddhist temple minutes from Centre Court

It helps a winner keep on winning
Is this the future of flying: battery-powered planes made of plastic, and without flight decks?

Is this the future of flying?

Battery-powered planes made of plastic, and without flight decks
Isis are barbarians – but the Caliphate is a dream at the heart of all Muslim traditions

Isis are barbarians

but the Caliphate is an ancient Muslim ideal
The Brink's-Mat curse strikes again: three tons of stolen gold that brought only grief

Curse of Brink's Mat strikes again

Death of John 'Goldfinger' Palmer the latest killing related to 1983 heist
Greece debt crisis: 'The ministers talk to us about miracles' – why Greeks are cynical ahead of the bailout referendum

'The ministers talk to us about miracles'

Why Greeks are cynical ahead of the bailout referendum
Call of the wild: How science is learning to decode the way animals communicate

Call of the wild

How science is learning to decode the way animals communicate