currentsinbiology:

Sperm wars

Why do male animals need millions of sperms every day in order to reproduce? And why are there two sexes anyway? These and related questions are the topic of the latest issue of the research journal Molecular Human Reproduction published today (Oct. 16th, 2014). The evolutionary biologist Steven Ramm from Bielefeld University Bielefeld has compiled this special issue on sperm competition. In nature, it is not unusual for a female to copulate with several males in quick succession – chimpanzees are one good example. ‘The sperm of the different males then compete within the female to fertilize the eggs,’ says Ramm. ‘Generally speaking, the best sperm wins. This may involve its speed or also be due to the amount of sperm transferred. It can also be useful for the seminal fluid to be viscous, meaning it sticks inside the female reproductive tract to try to keep other sperm at bay.’

Caption: Sperm come in all shapes and sizes: the sperm cell of the flatworm Macrostomum lignano (picture) has a frontal “feeler” (right) and two lateral bristles that may function to anchor the sperm inside the female sperm-receiving organ. Credit: Photo: Bielefeld University

currentsinbiology:

Sperm wars

Why do male animals need millions of sperms every day in order to reproduce? And why are there two sexes anyway? These and related questions are the topic of the latest issue of the research journal Molecular Human Reproduction published today (Oct. 16th, 2014). The evolutionary biologist Steven Ramm from Bielefeld University Bielefeld has compiled this special issue on sperm competition. In nature, it is not unusual for a female to copulate with several males in quick succession – chimpanzees are one good example. ‘The sperm of the different males then compete within the female to fertilize the eggs,’ says Ramm. ‘Generally speaking, the best sperm wins. This may involve its speed or also be due to the amount of sperm transferred. It can also be useful for the seminal fluid to be viscous, meaning it sticks inside the female reproductive tract to try to keep other sperm at bay.’

Caption: Sperm come in all shapes and sizes: the sperm cell of the flatworm Macrostomum lignano (picture) has a frontal “feeler” (right) and two lateral bristles that may function to anchor the sperm inside the female sperm-receiving organ. Credit: Photo: Bielefeld University

currentsinbiology:

Sperm wars

Why do male animals need millions of sperms every day in order to reproduce? And why are there two sexes anyway? These and related questions are the topic of the latest issue of the research journal Molecular Human Reproduction published today (Oct. 16th, 2014). The evolutionary biologist Steven Ramm from Bielefeld University Bielefeld has compiled this special issue on sperm competition. In nature, it is not unusual for a female to copulate with several males in quick succession – chimpanzees are one good example. ‘The sperm of the different males then compete within the female to fertilize the eggs,’ says Ramm. ‘Generally speaking, the best sperm wins. This may involve its speed or also be due to the amount of sperm transferred. It can also be useful for the seminal fluid to be viscous, meaning it sticks inside the female reproductive tract to try to keep other sperm at bay.’

Caption: Sperm come in all shapes and sizes: the sperm cell of the flatworm Macrostomum lignano (picture) has a frontal “feeler” (right) and two lateral bristles that may function to anchor the sperm inside the female sperm-receiving organ. Credit: Photo: Bielefeld University

To Tumblr, Love Pixel Union