Promiscuity: An Evolutionary History of Sperm Competition Chapter 1

I recently recommended Dr. Tatiana's Sex Advice to All Creation to someone and was reminded that I had Promiscuity waiting for me on the shelf upstairs. Over the next few posts I'll jot down a few notes and afterwards boil those down for your perusal along with a few of my personal observations. It should be noted that these posts will likely be extraordinarily graphic and thus not recommended for the faint of heart. That said, they should at least be interesting but don't expect it to hang together like a proper narrative since I'm just going over my notes not retyping the whole text.

Chapter 1

The Greeks, due to a surfeit of dead male soldiers to dissect had a really good idea of how the male member worked. The female form, however was a different story since dissection of a woman was strictly forbidden. Having observed various ob-gyns over 10 years of marriage it seems clear to me that not a lot has changed in the past 2000 years. The text admits, for example, that science currently doesn't know what physical function the clitoris performs. My wife, however, says SHE has a pretty good idea.

Erasmus Darwin introduced the concept that males in a species have secondary sexual characteristics such as large plumage displays or dangling wattles to attract females of the species in his 1792 text Zoonomia. In the 1960s, Bob Trivers postulated that the showiness of these displays is inversely proportional to the male's involvement with the young. To offer proof by anecdote, the peacock has a tremendous sexual display but his responsibilities end immediately after he inseminates the hen. Inversely, the male magpie invests heavily in his mate bringing her food throughout the entire brooding process and he is virtually indistinguishable from his hen.

In 1937 Geoff Parker introduced the idea that this competitiveness may even happen at the level of individual sperm. Parker examined dungflies, a species in which the female is approached by several males and noted that as a female approaches a patty several males wrestle for the opportunity to mate with her. It's in the female's best interest, Parker argues, to be inseminated by as many males as possible. Similarly, the male is best served who can not only inseminate a female but protect her from insemination by others. At the same time males who can fight through the attempts of other males to keep females to themselves have an advantage. What results is an arms race between males who attempt to protect their mates from intruders but also to overcome the defenses of others. Meanwhile the female benefits as long as multiple males assail her honor. And to help her make the distinction the female has evolved all manner of chemical and physical processes to put the competing sperm through the wringer to select only the best.