The Stanly News and Press (Albemarle, NC)

Features

October 18, 2013

Some animals are dying for love

There is a small mouse-like marsupial that lives in Australia, South America, and Papua New Guinea and that will die for love. In a brief and frenzied mating season, the males of this species will compete desperately for the attention of the females, mate frantically with them, and get so stressed out by the experience that they will die, tragically, like an army of Romeos. The phenomenon is known as "synchronized suicidal reproduction," or more technically, "semelparity." It is more common among plants, fish, and spiders than mammals, although biologists have known about this particular marsupial's reckless habits for at least 30 years.

What biologists haven't known is why the marsupial would willingly subject himself to such heartbreak, year after year. There have been several hypotheses floated over the decades, but as Diana Fisher of the University of Queensland and her team of researchers show in a paper published this month, those hypotheses are implausible. Fisher and her team spent more than a decade observing the mating behavior of the marsupials and broke through years of clotted thinking about the phenomenon. In so doing, they inadvertently reveal how even something so straightforward as biological observation gets thoroughly distorted by our narrow human lens on gender dynamics and sex.

The researchers compared 52 different species of a creature of the Dasyuridae family of marsupials from different habitats. For the species who live in higher latitudes, the insects they eat are only available in abundance for brief periods, and the females synchronize their mating season to coincide with the food. They send out the signal and the males come swarming. The males try to mate with as many females as possible in sex sessions that can last up to 14 hours. During these marathon bouts of copulation, the males release high levels of hormones, including testosterone, which in turn elevates stress hormones. "If we humans get huge stress, we have a feedback system and we bring it down," Fisher said. "But the marsupials just keep ramping it up more and more and are driven to spend all their time mating competitively."

Why did researchers fail to see for so long that females were the sexual aggressors?

For years there were two reigning theories about this phenomenon, both of which made the males seem quite noble. The first was that the males fight for the females, and that elevates their stress hormones. "This has not turned out to be true," Fisher wrote me. "They don't fight." And even if they did, she pointed out, fighting would be fast and intermittent, not long and sustained. The second theory was that the males are altruistic, and die off to ensure that there is sufficient food for the next generation, a reason commonly cited in nature documentaries. But Fisher calls this one "implausible" as well. Natural selection, she writes, acts at the level of individuals passing on their genes, not populations of males acting for the good of the species. In this case, the males "mate themselves to death" says Fisher, in order to ensure that they, and not the next marsupial, will get as many sperm as possible into the female. They just won't stop, until they are good and empty, and apparently they have very large testes so it takes a while.

In fact, what previous researchers have missed is that the mating behavior is entirely driven by the females. They synchronize their reproductive cycles to coincide with the available food, they determine the length of the mating season, and they are very, very promiscuous, mating with as many males as possible, indiscriminately — old, young, fit, not fit, any old marsupial will do. (In Fisher's paper she calls the females "polyandrous.") The males are powerless in this process and have very little agency. They have to adjust themselves to the schedule set by the females, and that schedule is so stressful that they die.

Apparently, overlooking female control is a common "oops" in animal mating research. Daniel Bergner's recent book, "What Do Women Want?" describes the great fallacy of monkey sex studies. For many years the reigning theory was that in rhesus monkeys, males initiate sex. But it turned out that this was only true in cages. Once they started to observe the monkeys in the wild, researchers saw something very different. The males would lurk at the edges of female-run domains. "The females invited them to serve sexually. The males remained — desirable, dispensable — until the females lost interest in them. Then they were dismissed, replaced." Why did researchers fail to see for so long that females were the sexual aggressors? Because we want to believe that "the female libido is limited and that women are monogamy's natural guardians," writes Bergner.

Luckily the blinkers are coming off. Fisher says that when molecular techniques to do genetic fingerprinting became more available and affordable in the 2000s, researchers realized that, for example, bird pairs once thought monogamous were doing a lot of "extra-pair mating," known in the human world as cheating, and that female promiscuity was fairly widespread in the animal kingdom. "It had not occurred to researchers that females were driving so much competition (and evolution) this way and it seemed surprising and needing explanation," says Fisher. "Now this field of sexual selection from the point of view of females gets a lot of attention." It takes years of patient observation to reverse received wisdom — a decade in Fisher's case. But it seems only a matter of time before marsupials start burning their bras.

1
Text Only
Features
  • Archie Smith Psaltery Sounds

    About two years ago, Archie Smith got into an argument with his table saw.
    As he says, the table saw won.

    June 30, 2014 3 Photos

  • P1160049_zps0528ec83.jpg Jammin' at Junior's

    Benjamin Franklin once wrote: “ … in this world nothing can be said to be certain, except death and taxes.” If Franklin was alive today in western Stanly County, he would need to amend his statement to include “and Friday night jam sessions at Junior Harris’.”

    June 17, 2014 2 Photos

  • KelliePickler_TheWomanIAm_LPCover.png Kellie Pickler set to release album with limited edition vinyl pressing

    NASHVILLE, Tenn. – Black River Entertainment announced the release of a limited edition vinyl version of country music singer/songwriter Kellie Pickler’s critically-acclaimed current album, The Woman I Am.  This is the first vinyl album for Kellie Pickler, and it features exclusive cover art, different from the CD version.

    June 16, 2014 1 Photo

  • wedding (12 of 21).tif Fairy Tales Can Come True

    Once upon a time in Stanfield a little girl was born, but experienced problems during her delivery. Five years earlier, a little boy was born in Georgia with similar complications. Both suffered a brain bleed during child birth and had ventricular shunts placed in their heads.

    June 16, 2014 3 Photos

  • Social networks are the new matchmakers

    WASHINGTON - With studies showing that one-third of married couples started their relationships online, finding romance via URLs is no longer as novel - and creepy - as it seemed when dating sites launched in the mid-1990s.

    June 9, 2014

  • Dive into the World’s Most Diverse Marine Ecosystem when Journey to the South Pacific Arrives at Discovery Place on June 7

    CHARLOTTE – Audiences will be taken on an epic IMAX® adventure through the tropical islands of West Papua and experience one of the most extraordinary places on Earth, when the IMAX film Journey to the South Pacific comes to Discovery Place on June 7.

    June 6, 2014

  • iphone4.jpg Five major new features in iOS 8

    Apple has taken the wraps off its latest mobile operating system, iOS 8, introducing a suite of new features to users aimed at streamlining some of their most annoying daily tasks.

    June 6, 2014 1 Photo

  • Singing2.jpg 90th Annual 'Singing on the Mountain' dedicated to the late Arthur Smith

    LINVILLE, N.C. — The 90th annual Singing on the Mountain at Grandfather Mountain will pay tribute to the late Arthur Smith, a legendary country, bluegrass and gospel musician and entertainer who died April 3.

    June 5, 2014 4 Photos

  • TattooShop3.JPG Quarter century of talent part of new tattoo business

    As Chriss Parks waits for his wife Barbara Parks’ horse tattoo to be constructed by Slingin Ink co-owner and ink slinger Ricky Tasker, his three children are shooting pool. Occasionally Chriss interrupts to teach the children the correct way to play the game.

    June 4, 2014 1 Photo

  • dog-sunglasses.jpg Do animals have a sense of humor?

    Right now, in a high-security research lab at Northwestern University's Falk Center for Molecular Therapeutics, scientists are tickling rats. Their goal? To develop a pharmaceutical-grade happiness pill. But their efforts might also produce some of the best evidence yet that humor isn't something experienced exclusively by human beings.

    March 29, 2014 1 Photo

House Ads
Hyperlocal Search
Premier Guide
Find a business

Walking Fingers
Maps, Menus, Store hours, Coupons, and more...
Premier Guide
Featured Comment
Twitter Updates
Seasonal Content
Poll

Will you participate in March Madness?

Yes I watch the games and complete a bracket.
Yes I complete a bracket.
No
     View Results