Strong Scents of Male

Making the rounds this week was this amusing and entertaining video from Mary Roach, author of several books - of which I've only read Spook - but Stiff is in my "to read" pile, as is "Bonk" - from which much of this material comes. (pardon)



The video is entertaining and informative - but the part that really struck me (besides the non-prurient pig masturbation) was the section that starts at the 5:30 mark. It highlights some of the work of researcher and writer Theodoor Hendrik van de Velde. In van de Velde's writing (per Roach) he mentions the smell of a mature man's semen as being similar to the scent of a Spanish Chestnut's flowers.

This brought to mind some research I'd done a long time ago on this matter. My wife said that a tree in the back yard of my mother's house smelled like semen when it flowers. I agreed with her and found it similar - yet slightly stronger like what I imagines a sperm bank with a faulty freezer unit might end up smelling like after a day or two.

Not content to just note the similarity, I looked around for any literature on the matter and came across a lengthy discourse on the "Straight Dope" board. Here's the link - but the page has a lot of additional material non-topical to this matter, so I'll include the salient quote. Always give "Cecil" a read if you have time, though.
This is a link to that article (down the page below the piercing question).

REPORTS FROM THE FRINGE, PART ONE

Dear Cecil:

Abhorrent as it is to speak of such matters, I must corroborate your reader's recent observation about certain trees in Los Angeles that smell like semen in the fall. I have two of these funky-smelling (in the original sense of the word meaning "bitch dog in heat") trees in my backyard in Laurel Canyon. They are ugly, have grotesque hairy blossoms, and smell so bad that bees and flies both share the nectar. It is disconcerting for me and I'm glad I'm not the only one to notice it. --R.H., Los Angeles

PS: I have no idea what they're called.

Dear R.H.:

I can see it's going to be one of those weeks. Due to the press of business, I haven't had had a chance to go hunt down the sperm trees of Los Angeles myself. However, David Lofgren, a botanical information consultant at the Los Angeles State and County Arboretum, speculates that the plant in question is the carob tree, Ceratonia siliqua, source of the well-known chocolate substitute. The tree, which grows only in Mediterranean climates like LA's, typically is around 30 feet tall and has bluish green leaves that are rounded on the end. At blossom time it has many little flowers, which may give the appearance of hairiness. In the fall and winter it produces sweet, juicy pods that conceivably could produce the smell of semen when they rot. However, if one of Cecil's devoted readers will be so kind as to send him a sample of the offending tree's leaves, blossoms, pods, or whatever, we will get to the bottom of this matter once and for all.
The discussion goes on from there... go to the SD page for the full discourse.

In "Cecil's" research he's referred to the Carob tree by botanist David Lofgren.
Also Ginko trees. (We have these at my office, and the smell shows up there sometimes.)
Florida "Punk Trees" are implicated.
California Privet.
A Chesnut. (Cecil postulates "Chinese" - but perhaps it was Spanish as in TvdV's example?)

"Cecil" comes to the conclusion that the correct tree hasn't been identified. Yet it seems more likely that a variety of trees produce a comparable odor. I wonder why? And is the chemical involved in the odor the same as that in Semen? Or is this a result of convergent evolution?

There may not be any benefit to having heavily scented semen. Especially if one is trying to convince a lover to swallow it. But based on my research (still preliminary) evolution doesn't favor oral sex for the benefit of the male. (Now female directed oral sex - that's all over the place in the animal kingdom.)

So if humans don't use scent for selection (though there is a lot of evidence that they DO in fact) then why have such a scent. And more importantly why have such a similar scent in multiple plants? Do we really want bees and flies attracted to semen? (I don't! - and I certainly don't want any honey produced by such a misguided hive.)

It's a mystery - but one worth investigating. I'll put this one on the list of "things to keep looking into" and get back to it in the future.