Stuck in the Food Web
adam October 8th, 2009
60 Minutes is broadcasting a report by Scott Pelley on African wildebeest migration. He’s narrating how wildebeest, at a certain point in their migration, have to cross the Mara River full of 15-foot crocodiles. As the herd begins to cross, a croc catches the head of a wildebeest between its jaws. Soon three, four, five other crocs know what’s up. They latch on. They kill it by drowning it. I thought crocodiles would’ve killed a wildebeest by biting it, but they drown it. Then they eat him.
What a miserable world we live in. Sometimes I don’t want to even be a part of it. I’m going to become a vegetarian and remove myself from this circle, elevate myself. Aren’t human beings above nature? Part of it, yes, but aren’t we civilized? I’m going to only eat from my garden, and that will be that. I’ll live by eating lettuces and beans and vegetables from the garden. No fear, no death. Just rows of plants. Harmless plants for a harmless guy.
I turn off the TV and open the book I’m reading, Teaming With Microbes: A Gardener’s Guide to the Soil Food Web. Fascinating stuff. Fungi and bacteria are at the bottom of the soil food web, and plants absorb their wastes as nutrients. So much activity in the zone around a plant’s roots, called the rhizosphere. But nothing like the horribleness of wildebeest-eating crocodiles.
But what’s this? Fungi are even better killers than crocodiles? The fungus Arthrobotry dactyloides releases a chemical to attract nematodes, roundworms smaller than a human hair that live in the soil. A looped strand on the fungus, consisting of three cells, swells three-fold when touched, trapping and killing the worm in one-tenth of a second. The strand then pierces the nematode’s body and begins extracting nutrients. Those nutrients, after a series of predators eating prey, will eventually become mineralized, making them available to plants, making them available to me when I eat the plant.
A food web is a food web, no matter the scale. For better or worse, this is the inescapable system we’re a part of.
Fungus trapping a nematode.
I saw a strange thing while I was jogging. I see this worm on the path high tailing across the path - I had never seen a worm moving so fast.
So I stop and look closer and he’s go a leech looking thing on his back.
And what the leech thing was doing was trying to hammer his head into the body of the worm. And the head of the leech had to spear point of some sort.
So this worm was crawling along so fast that the leech was riding a bucking bronco!
Of course I peeled the leech off and squashed the little parasite. I heard they a putting a big dent in the worm population too.