Chickens eject sperm from males they don't fancy

Aug 25, 2011
While sexual coercion is common in fowl, females are able to exert a strong influence on fertilization by differentially dumping sperm of individual males. Credit: Tommaso Pizzari

New research finds that even though hens aren't terribly picky about their mates, they are picky about whose sperm makes it to the egg.

Female domestic chickens generally mate with multiple males and are known to sometimes eject sperm following mating encounters.

It was unclear, however, whether the sperm ejection was a consequence of receiving a large amount of ejaculate, or because hens are actively trying to rid themselves of undesirable sperm.

A team led by Oxford researcher Rebecca Dean investigated the phenomenon in a group of feral chickens kept at Stockholm University in Sweden.

After controlling for ejaculate size and other factors, Dean and her colleagues found that ejected a larger proportion of inseminations by socially subordinate males.

"These results show that promiscuous females can actively bias sperm utilization to exert a strong and predictable influence on the struggle for fertilization," Dean said. By doing so, females "retain control of even in species such as fowl where males can force mating."

Explore further: Cheetahs found to use spatial avoidance techniques to allow for surviving among lions

More information: Rebecca Dean, Shinichi Nakagawa, and Tommaso Pizzari, "The Risk and Intensity of Sperm Ejection in Female Birds.", American Naturalist, September 2011.

add to favorites email to friend print save as pdf

Related Stories

Hens' sperm ejection secrets

Aug 03, 2011

In reproductive warfare sperm is a male’s ultimate weapon to decide who fathers the next generation.

Spread your sperm the smart way

Jul 09, 2009

(PhysOrg.com) -- Attractive males release fewer sperm per mating to maximise their chances of producing offspring across a range of females, according to a new paper on the evolution of ejaculation strategies. The findings ...

Rodent sperm work together for better results

Jan 24, 2007

Although, sperm are inseminated in millions each sperm goes it alone. However, under some circumstances it might be advantageous for sperm to cooperate with one another. This is especially likely to be the case when females ...

Does promiscuity prevent extinction?

Feb 25, 2010

Promiscuous females may be the key to a species' survival, according to new research by the Universities of Exeter and Liverpool. Published today (25 February) in Current Biology, the study could solve the my ...

Recommended for you

Genome yields insights into golden eagle vision, smell

13 hours ago

Purdue and West Virginia University researchers are the first to sequence the genome of the golden eagle, providing a bird's-eye view of eagle features that could lead to more effective conservation strategies.

User comments : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

Skepticus
not rated yet Aug 25, 2011
Men! The Feminists's Holy Grail.
Squirrel
not rated yet Aug 26, 2011
It should be noted that the males of most birds unlike mammals do not have "intromittent organ" commonly called penises. (Ducks and ostriches are exceptions.) Instead the male passes sperm by cloacal "kissing". It is thus much easier for the female chicken to be selective about sperm that gets used for fertilizing her egs.

More news stories

Genetic legacy of rare dwarf trees is widespread

Researchers from Queen Mary University of London have found genetic evidence that one of Britain's native tree species, the dwarf birch found in the Scottish Highlands, was once common in England.

Ocean microbes display remarkable genetic diversity

The smallest, most abundant marine microbe, Prochlorococcus, is a photosynthetic bacteria species essential to the marine ecosystem. An estimated billion billion billion of the single-cell creatures live i ...

Genetic code of the deadly tsetse fly unraveled

Mining the genome of the disease-transmitting tsetse fly, researchers have revealed the genetic adaptions that allow it to have such unique biology and transmit disease to both humans and animals.

Cell resiliency surprises scientists

New research shows that cells are more resilient in taking care of their DNA than scientists originally thought. Even when missing critical components, cells can adapt and make copies of their DNA in an alternative ...

Google+ boss leaving the company

The executive credited with bringing the Google+ social network to life is leaving the Internet colossus after playing a key role there for nearly eight years.