In one of his funniest movies, Everything you ever wanted to know about sex but were never afraid to ask, Woody Allen is a sperm. We see him chatting with others; sharing his fears because it was his first ejaculation. Allen’s visual joke insisted on that common idea that each sperm seeks life in its (theoretical) attempt to reach the egg.
The image breaks with the idea that spermatozoa are represented as individuals that compete with each other to fertilize the ovule”
But it turns out that it is not, that it is not a race between spermatozoa that compete to be the fastest and most skillful in reaching an egg. Nature, we see again, prefers cooperation to competition.. Researchers have just discovered that sperm form teams to reach the target faster.
In a article published this week in Frontiers in Cell and Developmental Biologyit is shown that the sperm come together to navigate the thick vaginal fluid. It doesn’t happen all the time, but it does happen often. The authors have seen it in a wide range of mammalian species.
“The picture breaks with the idea that represents spermatozoa as individuals that compete among themselves for fertilizing the ovum”, explains on his Twitter account the science popularizer Alex Richter-Boix.
Clumped sperm swim better
The team of scientists, led by Chih-Kuan Tung, a physicist at the North Carolina Agricultural and Technical State Universityhas carried out a series of experiments with sperm and a device that simulates the fluid of the female reproductive tract. They chose bovine sperm because of its resemblance to humans.
Bull sperm moving in a group like cyclists to better pass through the thick vaginal discharge. The image breaks with the idea that sperm are represented as individuals that compete with each other to fertilize the egg. pic.twitter.com/8wCF1mZrwm
— Alex Richter-Boix (@BoixRichter) September 22, 2022
They have found that sperm that travel in groups have more advantages than solitary ones, regardless of the strength of the fluid current they face. “We found that pooled sperm swam more oriented toward each other in the absence of flow, could swim upstream under intermediate flows, and resisted strong flow better than individual sperm,” the researchers note.
“It can resemble the formation of a peloton on a bicycle, although the fluid mechanics for sperm are drastically different”
According to Richter-Boix, “The picture of sperm acting individually is based on flat views on microscope slides or in other laboratory settings that do not reflect the natural conditions in which they move.” The truth is shown when you see them working on a three-dimensional model.
“It may look like formation of a cycling platoon, although the fluid mechanics for sperm are drastically different than for cyclists. We would certainly like to know more about this,” explains Tung.
Know that sperm work as a team It can have big implications for the future. The authors of the study refer, among others, to infertility treatments. But for that, they acknowledge, they need to better understand the physics of how sperm navigate vaginal fluid.
“In the longer term, our understanding may provide a better selection of sperm used for interventions such as fertilization. in vitro or others assisted reproductive technologies“, says the main author of the study.