An Open Letter to Vegetarians

I've enjoyed watching the seasons turn over in the meadows around my home. The fields are dominated by a resurgence of yellows and whites while roadside ditches are noticeably bare of pink and orange. The local fawns are losing their spots (and thankfully seem to be gaining caution around cars) while some bucks have sprouted velvety, 8+ point antlers.

This reminds me of a question I've always wanted to ask an intellectual vegetarian - "why?"

I admire those who make this big sacrifice in order to (profoundly) decrease their environmental footprint. Even a small decrease in meat consumption across the developed world would dramatically decrease agriculture's footprint.

I don't understand the moral argument though (as opposed to religious ones). Well, I do at first. It seems that all of ethics boils down to "it's wrong to hurt people." It's obvious and intuitive to extend this to animals, at least the more person-like ones.

A former professor of mine made the interesting observation that domesticated cats are obligate carnivores. Unlike dogs, cats can't be kept on a diet of rice and veggies. Does this mean it's unethical to keep cats as pets? I guess I could accept this corollary of vegetarianism, but it starts to lose me as I keep following it to its logical end.

Almost all vegetarians/environmentalists I've run into are big fans of reintroducing charismatic megafauna back into the wild lands our ancestors extirpated them from. The wolves of Yellowstone have been a particularly striking example. Biologists were amazed at the ecological transformation that followed the return of wolves. Wolves not only thinned out the overpopulated deer and elk herds, but created a "landscape of fear" that influenced where these herbivores travelled. Along streams, huge willow trees sprung up, spared from being browsed to the ground. Biologists hadn't even realized the willows were supposed to be there! Any Easterner who thinks hardwood forests are generally open and free of herbs and scrub have experienced this effect.

So if carnivores are required to maintain healthy and balanced ecosystems, why is it wrong for humans to participate? What difference am I missing between humans re-establishing wolves into Yellowstone and humans taking some of the prey directly? We're not really even an exotic species. Humans integrated into North American ecosystems after traveling over the Bering land bridge thousands of years ago, the same as any other major terrestrial carnivore.

I hesitate to wonder if the wolves are doing our "dirty work" for us. Most people don't hesitate to buy shrink-wrapped ham, but I don't know how many could bring themselves to kill and butcher a pig. I can't help but feel that vegetarianism might be a symptom of our disconnect with nature. No one likes death, but it's just the way this world works. We are part of the natural world, not foreign observers.

I'm especially concerned about the future ecological integrity of the eastern forests as the white-tailed deer population continues to explode. Much of this region is too densely-populated to re-establish wolves, mountain lions or bears and the number of U.S. hunters is cratering. What's the solution? Am I missing something?

Ultimately, it may be too much to ask people to explain their ethics. I'm reminded of a thought experiment that demonstrates how illogical morality is. Paraphrasing:

Imagine you see a speeding train. You know that if it continues on its track, it will kill 50 workmen around the next bend. If you throw the track switch in front of you, it will divert the train so it only kills 1 man. What would you do?
Now imagine there are still 50 men around the bend but there is no switch, only a man working near you. If you shove him in front of the train, it will stop before killing the other 50. What would you do then?

Most people would say "yes" to the first and "no" to the second, and most couldn't tell you why.

New Book - Where Locavores Get it Wrong

Science Friday today featured a feeble "debate" between James McWilliams, author of the new book "Just Food: Where Locavores Get It Wrong and How We Can Truly Eat Responsibly," Michael Pollan and Brian Halweil.

I was disappointed that none of the guests pointed out how silly it is to lump all pesticides and transgenic crops into a single category - as opposed to evaluating them individually by their unique properties - but overall I was glad to hear a more nuanced discussion of sustainability in agriculture then we are usually subjected to.

It's encouraging that the talking heads are making some progress towards a more sophisticated and accurate view of the world.

I Heart Smut Fungi

I was excited to find a fair amount of corn smut (Ustilago maydis) in our corn field today. It's one of my favorite fungi.

This fungal parasite has a complex lifecycle that culminates in the infection of a corn plant and the transformation of that plant (usually the kernels) into tumor-like mushrooms. When ripe, these rubbery gray growths rupture, releasing greasy, black spores.


But BEFORE this fungus produce spores, this "maize mushroom" exists as a yummy Mexican delicacy, known as "huitlacoche." It can be cooked up like any other mushroom. Sometimes you can find the canned version in specialty grocery stores, but I doubt it's as good as it is fresh.

Unfortunately, all the smut I found today had already gone to spores...


Another smut disease caused some pretty dramatic agricultural disasters at the turn of the century (before last). A series of devastating wheat smut outbreaks caused hundreds of combine fires as the vehicles stirred up massive clouds of oily smut spores, which were ignited by the movement of the machinery.


A third pretty incredible smut fungus is Microbotryum violaceum. This "anther smut" fungus parasitizes various flowers in the Caryophyllaceae (especially the campions, Silene spp.).

This fungus colonizes and spreads systemically throughout its host plant, permanently sterilizing it. It does this by forcing the plant's female flowers to grow male anthers (which usually contain pollen) and then REPLACING the pollen with its own spores (see picture) - which are then spread by pollinating insects to uninfected plants!

Yellow vs. White Corn

I spent today pollinating maize. My reward was an armful of sweet corn! (currently boiling...)

Like the picture to the right, today's ears contain a mix of white and yellow kernels.


The yellow of maize kernels (along with most yellows, oranges and reds of other fruit) is caused by the accumulation of carotenoids. This chemical class has often been associated with human health and includes such famous members as lycopene and beta-carotene.

One particular enzyme, phytoene synthase, plays a particularly important role in the accumulation of carotenoids. Maize has two different versions of this gene - one for synthesizing carotenoids in the kernel endosperm, and the other for synthesizing it everywhere else. White kernels lack a functional copy of the former phytoene synthase gene, and therefore aren't able to accumulate (yellow) carotenoids.

Ultimately, the color is determined by the combination of the mother plant's genotype in addition to the genotype of the individual pollen grain that fertilized each kernel.