Retrospectacle has a nifty post about plants and fungi that use foul odors (to humans) to attract their pollinators.

As I was about to this short and sweet little post, I noticed that in the stinky plant comments someone mentioned loving the smell of diesel fuel. This reminded me that I’d told Sean I would look to see if there was a readily available answer to the question, “Why do some people love the smell of gasoline?”

Which was in itself a digression because that conversation had started out as some artist friends explaining to me why they were upset and offended I’d tried to get them to go to a presentation on a State Department program that buys art to place in US Embassies. I think Sean changed the subject to weird science because I was being obtuse and he had to give me a stern lecture about how this was Imperialism and no self-respecting artist should ever do this. I understand his perspective now, I think.

And let’s face it, weird science is way more fun to contemplate than the fact that you offended everyone you know by suggesting something you thought naively thought was innocent but clearly isn’t. (Sorry, artists!) Learn something new everyday…

Back to the weird science – why do some people love the smell of gasoline? I didn’t find a reason, but I didn’t try very hard. A rather outdated site, basenotes.com, mentions DKmen, a discontinued men’s fragrance with basenotes of suede, tobacco, citrus and fuel resin. I’m guessing the scent didn’t stay on the market long because some people love those smells, others hate them. And some of them, synthetic or real apparently, are migraine triggers.

As I continued my search I got sidetracked reading Neuroscience for Kids well-done teacher’s module OUR CHEMICAL SENSES: 2. TASTE – Experiment: How Taste and Smell Work Together.

Reports from our noses and mouths alert us to pleasure, danger, food and drink in the environment. The complicated processes of smelling and tasting begin when molecules detach from substances and float into noses or are put into mouths. In both cases, the molecules must dissolve in watery mucous in order to bind to and stimulate special cells. These cells transmit messages to brain centers where we perceive odors or tastes, and where we remember people, places, or events associated with these olfactory (smell) and gustatory (taste) sensations.

After I’d finished reading this site, I remembered an entirely different conversation with Sean. I mentioned the elementary school experiment to demonstrate that not everyone is a PTC (phenylthiocarbamide) Taster. He had no earthly idea what I was talking about.

So I looked that up and found a brief article about PTC and natural selection.

A genetic variation seen worldwide in which people either taste or do not taste a bitter, synthetic compound called PTC has been preserved by natural selection, University of Utah and National Institutes of Health researchers have reported.

Phenylthiocarbamide (PTC) is not found in nature, but the ability to taste it correlates strongly with the ability to taste other bitter substances that occur naturally, especially toxins. Eons ago, the ability to discern bitter tastes developed as an evolutionary mechanism to protect early humans from eating poisonous plants.

This has implications beyond historical interest:

People who can taste PTC are less likely to eat cruciferous vegetables such as broccoli, according to Wooding, which could be a problem because these vegetables contain important nutrients. If the ability to discern bitter tastes discourages PTC tasters from eating broccoli, it also may have the advantage of dissuading them from inhaling the acrid smoke of cigarettes. “Among smokers, there seems to be an excess of PTC non-tasters,” Wooding said. “So it seems that PTC tasters are less likely to smoke.”

This led me to some research on PTC that I hadn’t seen before (or forgot about, entirely possible. Mind like a steel sieve and all that), “Independent evolution of bitter-taste sensitivity in humans and chimpanzees” (Nature 440, 930-934 (13 April 2006) | doi:10.1038/nature04655; Received 17 November 2005; Accepted 16 February 2006). You’ll need a subscription or other database access, but the upshot is that humans and chimps evolved the same genetic mechanism, but independently. But you probably figured that out from the title.

Then I got distracted at the BBC’s Ever Wonder About Food? site and all other digressions were forgotten.