udowodniono ze monogamia nie sluzy ludziom z biologicznego pkt widzenia.
Czlowiek nie jest stworzony do dlugich zwiazkow i dlatego dzieki monogamii
nasze geny nie ewoluuja, mamy mniejszy przyrost naturalny i pare innych
rzeczy.
Zanim zaczniecie na mnie wieszac psy odsylam do lektury
http://science.martianbachelor.com/Monogamy.html


i przeczytajcie tez ten art. o rozwiazlosci kobiet (sorry ale in English)

Dr Sid


This is not your father's birds and bees
Recent research challenges notion of female monogamy

Carol Cruzan Morton, Special to The Chronicle Monday, February 17, 2003

Bar the doors and break out the chastity belts, boys, because girls of most
species sleep around, and it's for their own good, if not yours.

For generations, biologists had assumed females to be naturally chaste,
while males were renowned for their promiscuity. Even Charles Darwin, who
invented the idea of sexual selection, didn't dare challenge the Victorian
morals of his day. Man evolved from ape, fine. But an immodest and lustful
Mother Nature? Heaven forbid!

Now, hundreds of studies and a spate of books are challenging that
conventional wisdom. Females of many species, it turns out, have evolved
strategies for passing on their genes that involve copulating with multiple
males -- and recognition of that fact is literally changing our view of the
birds and the bees.

"Natural selection, it seems, often smiles on strumpets," says evolutionary
biologist Olivia Judson, author of "Dr. Tatiana's Sex Advice to All
Creation," the most recent and entertaining book exploring the variety of
female harlotry.

"As a rule, loose females have more and healthier children."

To be sure, biologists are examining these questions in the dispassionate
light of scientific inquiry. In describing their theories, they prefer the
more neutral term "polyandry," meaning many males, instead of "promiscuity."
And they caution laypeople not to look to nature's own apparent infidelities
for any justification of their own behavior.

The misbegotten idea that males evolved to make love and females to demur
gained scientific currency in the late 1940s in fruit fly experiments by
Angus Bateman, a British scientist who reached his erroneous conclusions in
part because his experiments lasted only three or four days.

Had he run his experiments longer, he might have discovered that male black-
bellied fruit flies secrete an anti-aphrodisiac in their semen that's
relatively short lived. As soon as it runs out, females become interested in
copulating again.

On the surface, the conventional view made sense. Sperm seemed to come cheap
to males, while eggs were expensive to females, which have to invest the
time to raise offspring. Scientists could not fathom any possible benefit of
multiple partners of females, and they could come up with plenty of
potential costs, such as sexually transmitted diseases.


BIRDS DO IT
Then came DNA paternity testing. In one species after another, it turned out
that biologists were as cuckolded as the males they had been observing. The
first and most extensive examples of polyandry were found among avian
species, which was quite a shock to scientists because birds had appeared to
be paragons of traditional family values.

"The way the male and female rush back and forth to their demanding brood of
chicks seems like nature's model of good parenting," says Marlene Zuk,
biology professor at UC Riverside and author of "Sexual Selections: What We
Can and Can't Learn About Sex From Animals."

"Now, we find that they're actually in the same situation as millions of
modern-day husbands and wives, eyeing a child warily and making uneasy jokes
about the milkman," she says.

DNA testing in chicks of seemingly monogamous females showed a wide range of
extra mates. In one study, for example, as much as 90 percent of the
offspring of the brilliantly colored Australian fairy wren were from mates
other than the presumed father.

Biologists have struggled to come up with broad theories for why females
benefit from playing the field, but so far the reasons seem to vary widely
according to species. A lot of complex theory boils down to this: A gal's
got to do what's necessary to ensure the survival of her genes.

In some cases, females may get more help around the home. Among bronze-
winged jacana, for example, harems of up to four males do all the child
care, enabling a female to have four times as many broods. Male greater
rheas, flightless South American birds that resemble ostriches, receive eggs
from several females, incubate them and rear all the chicks, while females
go off to mate and lay other clutches.

In other cases, females swap sex for food -- the more sex, the more food and
the healthier their offspring.

Among green-veined white butterflies, for example, a virgin male ejaculates
a sperm packet roughly 15 percent of his weight that also contains
nutritious substances. Females that have sex with several virgins lay more
and bigger eggs than those that do it with only one or with males that have
lost their virginity and consequently make sperm packets only half the size
of their virgin glory.


SURVIVAL OF THE LOOSEST
In other cases, promiscuity is simply a matter of survival. Male
chimpanzees, for example, have been known to kill infants not their own.
Frequent sex with several males -- in one 15-minute period, a female was
observed having sex with eight males -- can heroically confuse paternity and
act as insurance against harm to her offspring.

But while females are busy ensuring their genetic survival by sleeping
around, males have not been idle. After all, female promiscuity puts the
genes of males at risk. It's no good being Don Juan, seducing all the
females in sight, if none of them uses your sperm, Judson says. So males
have developed counterstrategies to ensure their genetic survival.

"This is perhaps the most significant discovery of the past two decades,
that male and female attributes coevolve," writes Tim Birkhead, professor of
behavioral ecology at the University of Sheffield in Britain and author of
"Promiscuity: An Evolutionary History of Sperm Competition."


SOME MALES' WEAPONS LETHAL
In the arms race between the sexes, males of some species have developed
penises that are more than sperm delivery devices.

Damselflies, close relatives of dragonflies, have penises with inflatable
balloonlike bulbs, two horns at the tip and long bristles down the sides. In
one species, males use this to scour sperm from inside a female before
depositing his own. In another, males use it for extra stimulation, inducing
her to eject sperm from previous lovers.

Male honeybees, on the other hand, sacrifice themselves on the altar of
love. Upon climax with the queen, he explodes, and his genitals rip from his
body, leaving the mutilated member as a kind of chastity belt.

"You might imagine that male honeybees would have evolved some way of
removing the chastity belt. You'd be right," Judson says. "If you look
closely,

you'll see that each male honeybee sports, on the tip of his phallus, a
hairy structure that can dislodge the severed genitalia of his predecessor."

Other species resort to guarding their mates. A possessive postcoital male
Idaho ground squirrel, for example, won't let his partner out of his sight
and follows her everywhere, stationing himself at the entrance to her burrow
and picking fights with other males that happen to come near.

When it comes to Homo sapiens, scientists urge us not to read too much into
all this. Depending on their point of view, people may be horrified or
intrigued by the infidelity of the birds and the bees, but in truth birds
aren't cheating, they're just doing what they do.

"If we try and use their behavior as a model or justification for our own,"
says Zuk, the UC Riverside biologist, "we not only run the risk of making
decisions about our morals on very shaky grounds, we miss what is
interesting and vital about the animals' own behavior."
----------------------------------------------------
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NEW LOOK AT REPRODUCTION
Females of many species have sex with multiple partners. Males, in turn,
have adapted ways to ensure that their genes, and not those of competitors,
are passed on. Understanding this co-evolution is changing our view of male
and female sex roles.

Among reed buntings, small brown songbirds, every male a female has mated
will come flying to her defense. But her infidelity can backfire if the
female's main squeeze suspects her of cheating.

Male honeybees sacrifice themselves on the altar of love. Upon climax with
the queen, he explodes and his genitals rip from his body, leaving the
mutilated member as a kind of chastity belt.

Male chimpanzees sometimes murder infants not their own. So females have
adopted a strategy of confusing paternity by having frequent sex with
several males.