Latest Sperm competition Stories

Leafcutter ant queens can live for twenty years, fertilizing millions of eggs with sperm stored after a single day of sexual activity.Danish researchers who have studied ants at the Smithsonian Tropical Research Institute in Panama since 1992 discovered that in both ant and bee species in which queens have multiple mates, a male's seminal fluid favors the survival of its own sperm over the other males' sperm. However, once sperm has been stored, leafcutter ant queens neutralize male-male...

Spermatozoa from the same individual cluster together, improving motility in the race to the eggSome mouse sperm can discriminate between its brethren and competing sperm from other males, clustering with its closest relatives to swim faster in the race to the egg. But this sort of cooperation appears to be present only in certain promiscuous species, where it affords an individual's sperm a competitive advantage over that of other males.The work is described this week in the journal Nature...

British scientists say they've found some female insects can control the amount of sperm they store in an effort to select the best father for their young. University of Exeter researchers say their findings represent new evidence to explain how some female insects can influence the father of their offspring, even after mating with up to 10 males. The scientists, led by postdoctoral researcher Amanda Bretman, made the discovery during research involving female crickets, which often mate with...

Females control sperm storage to pick the best fatherScientists have found new evidence to explain how female insects can influence the father of their offspring, even after mating with up to ten males. A team from the University of Exeter has found that female crickets are able to control the amount of sperm that they store from each mate to select the best father for their young.The research team believes the females may be using their abdominal muscles to control the amount of sperm stored...

Attractive males release fewer sperm per mating to maximize their chances of producing offspring across a range of females, according to a new paper on the evolution of ejaculation strategies. The findings by researchers at UCL (University College London) and the University of Oxford suggest that, paradoxically, matings with attractive males may be less fertile than those with unattractive ones.In a paper to be published in the journal American Naturalist, the team mathematically modeled a...

"Every sperm is sacred. Every sperm is great. If a sperm is wasted, God gets quite irate," goes the song from Monty Python's movie The Meaning of Life. If the lyrics strike you as funny, it's most likely because calling a sperm cell "sacred" sounds ridiculous when men can produce so many of them. In fact, the average male will produce roughly 525 billion sperm cells over a lifetime and shed at least one billion of them per month. A healthy adult male can...

Variety is the spice of life: too many males, too little time...Female Australian painted dragon lizards are polyandrous - that is, they mate with as many males as they can safely get access to. This promiscuous behavior is often found in species where male quality is dubious and there are high levels of infertility in the male population. Female painted dragons possess the remarkable ability to store sperm inside their reproductive tract that remain viable for a considerable amount of time,...

Fakery is seen throughout the animal kingdom and is especially evident in the realm of mate selection and mating behavior. A puzzling behavior frequently observed in many species is copulation between males and females without the delivery of semen. In a world where reproduction is key to a species, survival, such behavior poses a real mystery. In a study that sheds new light on the evolution of sexual behavior, researchers have utilized a novel technique to reveal that in feral chickens, the...

Genetic influences on variation in female orgasmic function: a twin study by Dr KM Dunn, Dr LF Cherkas and Prof TD Spector (DOI: rsbl.2005.0308 Ref: 05BL0033) Women in the general population commonly report difficulty achieving orgasm, but the causes of this are unclear as are the reasons for the large variations between women. One possible explanation is a role for genes. 4037 female twins from the TwinsUK register were surveyed confidentially about sexual problems. A sizeable genetic...