Reproduction: A-Courting To Nature

For some time she had watched his movements, appearing
coyly in his haunts. And now, had it paid off? Doubtless,
he was in love. His muscles were taut; he swooped through
the air more like an eagle than a Greylag gander. The only
problem was, it was not for her that he then landed in a
flurry of quacks and wingbeats, or for her that he dashed
off surprise attacks on his fellows. It was, rather, for
another - for her preening rival across the Bavarian lake.
 
Poor goose. Will she mate with the gander of her dreams? Or
will she trail him for years, laying infertile egg clutches
as proof of her faithfulness? Either outcome is possible in
an animal world marked daily by scenes of courtship,
spurning and love triumphant. And take note: these are not
the imaginings of some Disney screen-16 writer. Decades ago
Konrad Lorenz, a famed Austrian naturalist, made detailed
studies of Greylags and afterwards showed no hesitation in
using words like love, grief and even embarrassment to
describe the behavior of these large, social birds. At the
same time he did not forget that all romance - animal and
human - is tied intimately to natural selection.
 
Natural selection brought on the evolution of males and
females during prehistoric epochs when environmental change
was making life difficult for single-sex species such as
bacteria and algae. Generally, these reproduced by
splitting into identical copies of themselves. New
generations were thus no better than old ones at surviving
in an altered world. With the emergence of the sexes,
however, youngsters acquired the qualities of two parents.
This meant that they were different from both - different
and perhaps better at coping with tough problems of
survival. At the same time, nature had to furnish a new set
of instincts which would make "parents" out of such
unreflective entities as mollusks and jellyfish..
 
The peacock's splendid feathers, the firefly's flash, the
humpback whale's resounding bellow - all are means these
animals have evolved to obey nature's command: "Find a
mate. Transmit your characteristics through time!" 

But while most males would accept indiscriminate mating,
females generally have more on their minds. In most
species, after all, they take on reproduction's hardest
chores such as carrying young, incubating eggs and tending
newborns. Often they can produce only a few young in a
lifetime, so it's no surprise that the "ladies" are choosy.
They want to match their characteristics with those of a
successful mate. He may flap his wings or join a hockey
team, but somehow he must show that his offspring will not
likely be last to eat or first in predatory jaws.
 
Strolling through the Australian underbrush that morning,
she had seen nothing that might catch a female bowerbird's
eye. True, several males along the way had built avenue
bowers - twin rows of twigs lined up north and south. True,
they had decorated their constructions with plant juices
and charcoal. Yet they displayed nothing out front! Not a
beetle's wing. Not a piece of flower. Then she saw him. He
stood before the largest bower and in his mouth held a most
beautiful object. It was a powder blue cigarette package,
and beneath it there glinted a pair of pilfered car keys.
Without hesitation she hopped forward to watch his ritual
dance. 

Males have found many ways to prove their worth. Some, like
bowerbirds, flaunt possessions and territory, defending
these aggressively against the intrusion of fellow males.
Others, like many birds and meat-eating mammals, pantomime
nest building or otherwise demonstrate their capacity as
dads. Still others, however, do nothing. Gentlemen may
bring flowers, but most male fish just fertilize an egg
pile some unknown female has left in underwater sand. For a
fish, survival itself is a romantic feat. For other
species, though, love demands supreme sacrifices.
 
Shortly after alighting on the back of his mate, the male
praying mantis probably had no idea what was in store. This
would have been a good thing too, because as he continued
to fertilize his partner's eggs, she twisted slowly around
and bit off his head. She continued to put away his body
parts until well nourished and thus more able to sustain
her developing young. Luckily for most species, the urge to
mate comes on only occasionally, usually in springtime. For
love can hurt, particularly if your intended has difficulty
telling a mate from a meal. Pity the poor male of the
spider species, Xysticus Cristatus, for instance. His only
hope of survival is to tie a much larger female to the
ground with silk thread, and keep her there.
 
Every time a moth releases its attracting scent, or a
bullfrog sings out its mating call, these animals are
risking a blind date with some predator. Such alluring
traits have long puzzled scientists, particularly those
which seem not only risky but useless as well. Why, after
all, should a frigate bird mate more if he puffs out an
extra large red throat sac? How does ownership of such a
thing indicate a superior individual? Until recently, the
question stymied biologists, but then researchers in the
U.S. and Sweden announced a possible answer. While studying
widowbirds, among whom extravagant tail feathers are "hip",
they discovered that the longest-tailed males also carried
a lower number of blood parasites. Sexual ornamentation
seemed to be a means by which males could show of
superfluous health and energy. All of which may bring us to
fast sports cars, flashy clothes and other accessories of
the human suitor. After all, if he can afford dinner at the
city's most expensive restaurant, chances are he could
finance a baby too.