Filed under Evolution of sex

Manipulating the mouse penis bone, with science

Manipulating the mouse penis bone, with science

The girth of a mouse penis bone depends on the stiffness of the competition. That’s what Leigh Simmons and Renée Firman at the University of Western Australia found after several generations of experimental evolution in mice. Over the course of the experiment, male mice developed thicker penis bones (or bacula, if you want to be scientific about … Continue reading

The origins of monogamy in humans

The origins of monogamy in humans

Why humans evolved to be in monogamous relationships is still a bit of a mystery, but new research suggests it came about as a way to prevent infanticide. To learn more, check out Carl Zimmer’s article about this research in the New York Times HERE.

Absence makes the genitalia grow weirder

Absence makes the genitalia grow weirder

Evolution loves penises. How else do you explain all the crazy penis shapes out there? Por ejemplo (slightly nsfw): the corkscrew duck penis, the spiny cat and chimp members, the sci-fi-esque spiked penis of a seed beetle, the 4-headed penis of the echidna, and, well, all of these. Why so many ways to make a sperm … Continue reading

The secret sex of cheese

The secret sex of cheese

Are you grossed out by blue cheese? (I’m not, but I know many who are). Does that blue-green marbling of delicious fungus kind of make you gag? Well, this little factoid probably won’t help: there may be sex going on in that cheese. Until pretty recently, a big chunk of fungal species were thought to … Continue reading

Sex or no sex, that is the question

Sex or no sex, that is the question

There are pros and cons to everything in life, and sex is no exception. From an evolutionary biology standpoint, sex is a compromise (which may explain why so many of our lawmakers seem to be against it). Reproducing asexually means you don’t have to share with anyone else: all your genes get packed into each … Continue reading

The making of a toad, through sex and cloning

The making of a toad, through sex and cloning

At a certain age, children want to know the answer to one simple question: how are babies made? And the answer seems simple enough, too (if sometimes a bit awkward): one sperm plus one egg equals a baby. But this simple scenario breaks down quickly if we look around the animal kingdom (I won’t even … Continue reading

Older worms have more sex appeal

Older worms have more sex appeal

C. elegans are tiny worms that exist as hermaphrodites or rare males. A male rubs against a hermaphrodite with the mating apparatus on his tails and if he thinks she’s sexy enough, he’ll try to mate with her. And what turns on a male worm? Answer: an older lady. No one knows what the male … Continue reading

Evolution, sex, and spiky penises

Evolution, sex, and spiky penises

Male seed beetles (Callosobruchus maculatus) have long spikes covering their penises (or adeagus, if you want to be scientific about it). These spikes are thought to have evolved in response to female promiscuity, as a way of increasing the male’s chances of fertilizing a female’s eggs. Females, in response to the spikes, have evolved every man’s worst … Continue reading

Will male cottony cushion scales survive their own mating strategy?

Will male cottony cushion scales survive their own mating strategy?

A friend of mine just brought my attention to this article in the New York Times Science section today. An insect known as the cottony cushion scale (Icerya purchasi) exists in two sexes: hermaphrodites and males. Here’s the twist: the hermaphrodites are females infected with the parasitic tissue of a male (her “father”). This parasitic tissue is able to act as the male part of … Continue reading

Save some of that sperm for later

Save some of that sperm for later

In spiders, there are many species where the males only get one chance to pass on their genes. They stop making sperm as soon as they become adults, and after one sexual encounter, their sperm are all used up. In the great game of evolution, this isn’t the best strategy. They’ve quite literally put all their eggs in one basket. … Continue reading

Size matters for fruit flies

Size matters for fruit flies

When males are competing with each other for fertilization of a female’s eggs, which counts more: the number of sperm, or the size of each sperm? You might wonder why a guy can’t have it all but, alas, nature does make restrictions on how much energy one can devote to pumping out sperm. So which … Continue reading

Parasites give snails an incentive for sex

Parasites give snails an incentive for sex

Among the New Zealand mud snail (Potamopyrgus antipodarum), some do it, some don’t. Have sex, that is. Just how many snails live the sexual life is determined, in large part, by how many snails in the population are infected by parasites, according to new research by Kayla King, Jukka Jokela, and Curtis Lively. The findings … Continue reading