Nav: Home

What we're learning about the reproductive microbiome

January 14, 2020

Most research has focused on the oral, skin, and gut microbiomes, but bacteria, viruses, and fungi living within our reproductive systems may also affect sperm quality, fertilization, embryo implantation, and other aspects of conception and reproduction. Yet, according to a review published January 14 in the journal Trends in Ecology & Evolution, little is known about the reproductive microbiome.

What we do know is that there are examples of microbes affecting sexual health and fertility across the animal kingdom, and that these impacts seem to have important consequences for reproductive biology and behavior.
  • In human men, certain species of bacteria are associated with higher- or lower-quality sperm samples, while higher quantities of bacteria are more prevalent in semen samples from infertile than fertile men.
  • A study of primates showed that vaginal microbiomes are more diverse in species in which females have more than one sexual partner. Similar findings have been reported in deer mice and in common lizards.
  • Male mallards with more colorful bills produce semen better able to kill bacteria, leading researchers to speculate that female mallards sometimes choose partners with more colorful bills to reduce the risk of STDs, minimize disruption to their own microbiome, and ensure they receive high quality sperm.
  • Male bedbugs inseminate a female by piercing her abdomen. Recent work indicates that females, which can die from infections caused by microbes on the male copulatory organ, ramp up their immunological defenses ahead of mating.
  • In black garden ants, the testes of virgin males appear to favor microbial growth while the sperm-storage organs of virgin females strongly inhibit microbial growth.
  • Male red junglefowl, a wild ancestor of the domestic chicken, produce more proteins with antimicrobial effects in their ejaculate over successive matings--possibly to better protect dwindling numbers of sperm.
"Reproductive microbiomes can have significant effects on the reproductive function and performance of both males and females," says senior author Tommaso Pizzari, a zoologist at the University of Oxford. "These studies also shed light on the role of the reproductive microbiome in sexual selection, mating system, and sexual conflict."

While research has begun to link alterations in the vaginal microbiome to adverse pregnancy outcomes in humans, it's unclear how the male reproductive microbiome affects fertility and reproductive success, says first author Melissah Rowe (@melissah_rowe), an evolutionary ecologist who studies reproductive biology and behavior at the Netherlands Institute of Ecology.

"This is surprising, because research has shown that bacteria can damage sperm form and function, and that damaged sperm can contribute to pregnancy failure" Rowe says.

Many major questions remain. Rowe and Pizzari are intrigued by how some microbes benefit one sex or species while harming another. For example, Lactobacilllus--associated with a healthy vaginal microbiome in women and high-quality semen in men--seems to negatively affect sperm-swimming speed in chickens. But the authors say that the combination of sequencing advances, genomic resources, and investigations of host sexual behavior will likely lead to more discoveries soon.
-end-
This work was supported by the Research Council of Norway.

Trends in Ecology & Evolution, Rowe et al.: "The Reproductive Microbiome: An Emerging Driver of Sexual Selection, Sexual Conflict, Mating Systems, and Reproductive Isolation" https://www.cell.com/trends/ecology-evolution/fulltext/S0169-5347(19)30325-8

Trends in Ecology & Evolution (@Trends_Ecol_Evo), published by Cell Press, is a monthly review journal that contains polished, concise and readable reviews, opinions and letters in all areas of ecology and evolutionary science. It aims to keep scientists informed of new developments and ideas across the full range of ecology and evolutionary biology--from the pure to the applied, and from molecular to global. Visit: http://www.cell.com/trends/ecology-evolution. To receive Cell Press media alerts, please contact press@cell.com.

Cell Press

Related Bacteria Articles:

Bacteria might help other bacteria to tolerate antibiotics better
A new paper by the Dynamical Systems Biology lab at UPF shows that the response by bacteria to antibiotics may depend on other species of bacteria they live with, in such a way that some bacteria may make others more tolerant to antibiotics.
Two-faced bacteria
The gut microbiome, which is a collection of numerous beneficial bacteria species, is key to our overall well-being and good health.
Microcensus in bacteria
Bacillus subtilis can determine proportions of different groups within a mixed population.
Right beneath the skin we all have the same bacteria
In the dermis skin layer, the same bacteria are found across age and gender.
Bacteria must be 'stressed out' to divide
Bacterial cell division is controlled by both enzymatic activity and mechanical forces, which work together to control its timing and location, a new study from EPFL finds.
How bees live with bacteria
More than 90 percent of all bee species are not organized in colonies, but fight their way through life alone.
The bacteria building your baby
Australian researchers have laid to rest a longstanding controversy: is the womb sterile?
Hopping bacteria
Scientists have long known that key models of bacterial movement in real-world conditions are flawed.
Bacteria uses viral weapon against other bacteria
Bacterial cells use both a virus -- traditionally thought to be an enemy -- and a prehistoric viral protein to kill other bacteria that competes with it for food according to an international team of researchers who believe this has potential implications for future infectious disease treatment.
Drug diversity in bacteria
Bacteria produce a cocktail of various bioactive natural products in order to survive in hostile environments with competing (micro)organisms.
More Bacteria News and Bacteria Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Reinvention
Change is hard, but it's also an opportunity to discover and reimagine what you thought you knew. From our economy, to music, to even ourselves–this hour TED speakers explore the power of reinvention. Guests include OK Go lead singer Damian Kulash Jr., former college gymnastics coach Valorie Kondos Field, Stockton Mayor Michael Tubbs, and entrepreneur Nick Hanauer.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.