Male chemistry primes females for reproduction—but at a cost

September 8, 2016, Northwestern University
Caenorhabditis elegans. Credit: Wikipedia

A research team led by a Northwestern University scientist has discovered that male animals, through their invisible chemical "essence," prime female animals for reproduction but with the unfortunate side effect of also hastening females' aging process.

"The male signals trigger the female to 'go for it'—to put more effort into reproduction—but then the body suffers," said Ilya Ruvinsky, of the department of molecular biosciences at Northwestern's Weinberg College of Arts and Sciences. "There is a fine balance between reproduction and body maintenance, and this balance can be tipped by the male. We now are starting to tease apart this complexity."

Using the tiny transparent roundworm C. elegans, a well-established model for biomedical research, Ruvinsky and Erin Z. Aprison identified two distinct signals produced by males that affect female reproduction. The females sense the signals and respond by altering their physiology.

"We were investigating how animals reproduce under conditions that are closer to natural environments than the cushy life in the laboratory when we found this," Ruvinsky said. "One signal causes an earlier onset of puberty in juvenile females. The other slows down aging of the reproductive system in mature females, keeping them fertile longer. However, it also speeds up aging of the body."

A male animal doesn't even have to be present to cause these changes in a female—a miniscule amount of two male pheromones is enough to affect aging. Pheromones are small molecules produced and released by animals into the environment to alter the physiology or behavior of other members of the species. Although the signals target reproduction, even sterile females—ones without eggs—experience these profound changes.

"Our results regarding puberty onset echo previous findings in mice," Ruvinsky said. "In mammals, males also produce signals that manipulate the timing of sexual maturation of females. This raises an intriguing possibility that a basic mechanism controlling the rate of sexual development is similar in all animals. Because of this universality, our findings may have implications for humans."

Fortunately, the research suggests that the effects on sexual maturation, the reproductive system and overall body health can be separated, providing an area for future study. Understanding these basic mechanisms could lead to therapies that delay puberty and prolong fertility in humans as well as combat aging.

The study offers a simple explanation for a curious biological phenomenon: Male signals do not so much aim to harm females, but instead act to maximize females' readiness for reproduction.

"The harmful effects appear to be collateral damage, rather than the goal," Ruvinsky said.

Ruvinsky and Aprison used genetics and imaging to characterize female responses to male signals, including prolonged fertility and decreased longevity. They also demonstrated that steroid hormones, which are involved in a wide variety of developmental and physiological processes in all animal species, play a key role in converting a male signal into faster in .

The researchers conducted their work using C. elegans because this simple organism of barely 1,000 cells is easy to manipulate, has a short lifespan and offers a tremendous arsenal of experimental tools. This laboratory workhorse, affectionately called "the worm," has previously yielded numerous insights into basic biological phenomena that have dramatic implications for human health.

The study will be published online Sept. 8 by the life sciences journal Current Biology. The research also will appear in print in the Oct. 24 issue.

The paper is titled "Sexually antagonistic male signals manipulate germline and soma of C. elegans hermaphrodites." The research was conducted at the University of Chicago, with which Ruvinsky and Aprison were affiliated before moving to Northwestern.

Explore further: Female animals look drab to avoid sexual harassment, study shows

More information: Current Biology, DOI: 10.1016/j.cub.2016.08.024 , http://www.cell.com/current-biology/fulltext/S0960-9822(16)30936-8

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15 comments

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MR166
not rated yet Sep 08, 2016
Ah this might very well be the pinnacle achievement in the woman's lib movement. Just being near a man is harmful to your health!
Pooua
1 / 5 (1) Sep 08, 2016
I do not avoid women, but I do deny them my essence.

Frankly, I'm surprised that this article says nothing of the life-shortening effect of women on men. I've long suspected that sexual maturity shortens all lifespans.
Scroofinator
not rated yet Sep 08, 2016
Frankly, I'm surprised that this article says nothing of the life-shortening effect of women on men


It goes both ways, and it's really not that complicated. The average mammal has around 1 million heart beats in a life time, love/lust/gettin busy all increase heart rate. It's all about how long it takes you to get to the magic number.
TheGhostofOtto1923
not rated yet Sep 08, 2016
"... the unfortunate side effect of also hastening females' aging process"

-I suppose this is payback for the females natural tendency to make potential mates compete for her affections in order to discern the more qualified.

This also has the effect of shortening a males lifespan, often dramatically.
https://www.youtu...FIiLHXBc
https://www.youtu...4mSC6T78
https://www.youtu...8gmEVA18
https://www.youtu...FjUijxjY
(they never felt so alive)
Tektrix
5 / 5 (1) Sep 08, 2016
. . . but I do deny them my essence.


We're doing just fine without it.
retrosurf
not rated yet Sep 08, 2016
Pooua, do women sense your power and seek your life essence?

The reason the article says nothing about womens' effect on mens' lifespans is because the article is about tiny transparent roundworms, not men and women.
RealScience
not rated yet Sep 08, 2016
The average mammal has around 1 million heart beats in a life time.


Looks like a typo: Do you mean 1 Billion (10^9) rather than 1 Million (10^6)?
(A heart beating 60/minute reaches a million beat in less than two weeks...)

TogetherinParis
not rated yet Sep 08, 2016
The authors fail to cite the pheromone literature whereby puberty acceleration pheromone has been studied exhaustively in many species. Drickamer.
Thorium Boy
1 / 5 (1) Sep 09, 2016
. . . but I do deny them my essence.


We're doing just fine without it.


Darn fluoridation!!
Thorium Boy
not rated yet Sep 09, 2016
Now if only they could direct that energy to produce female children exclusively. Female children are being aborted by 3rd worlders in their home countries and the West at a rate of 60:1 over males. Surprised feminists haven't screamed about it.
TheGhostofOtto1923
not rated yet Sep 09, 2016
Now if only they could direct that energy to produce female children exclusively. Female children are being aborted by 3rd worlders in their home countries and the West at a rate of 60:1 over males. Surprised feminists haven't screamed about it
This was likely an implicit part of their efforts to reduce growth. They knew full well that limiting the number of children per family in that ancient culture would compel parents to abort females. And culling females is after all the most effective way of reducing growth.

This is also why it is necessary to attack population centers during demographic wars. Destroying armies while leaving the means of replacing them intact only leads to another war.

Consider how quickly the potential was restored after ww1.

Women are also the traditional carriers of culture. They are most influential in their children's identification with it. They are the reason men fight and die to preserve it.

'Deutsche frauen Deutsche Treue...'
TheGhostofOtto1923
not rated yet Sep 09, 2016
And you're completely wrong in your use of the term third world.

"Third World
noun
the developing countries of Asia, Africa, and Latin America."

-The third world is where abortions AREN'T occurring due to religion, which is why overpopulation and the resulting suffering and conflict are rampant.

The most important site on the internet
http://www.johnst...bortion/
Scroofinator
5 / 5 (1) Sep 09, 2016
Looks like a typo: Do you mean 1 Billion

Ya, good catch! Thanks for the edit
tinitus
Sep 09, 2016
This comment has been removed by a moderator.
BrettC
5 / 5 (1) Sep 09, 2016
Any triggering mechanism would indicate an efficiency system. Otherwise it would be turned on by default.

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