Monday, March 29, 2010

Suicide by Robin

"All worms have male and female reproductive parts. This means that all worms can mate with each other." (1)

"The good thing about being bisexual is that it doubles your chance of a date on a Saturday night." Woody Allen

So with every conceivable possibility for a rewarding sex life, why (every spring) do these slimy slitherers schlep out of my sodden sod and attempt to commit "suicide by robin" on my equally saturated driveway?

A[nswer]. Dr. Dennis Linden, Cindy Hale, and other worm experts say that worms do NOT surface to avoid drowning. In fact, they come to the surface during rains (especially in the spring) so they can move overland. The temporarily wet conditions give worms a chance to move safely to new places. Since worms breathe through their skin, the skin must stay wet in order for the oxygen to pass through it. After rain or during high humidity are safe times for worms to move around without dehydrating. It is true that, without oxygen, worms will suffocate. But earthworms can survive for several weeks under water, providing there is sufficient oxygen in the water to support them. (2)

When I was a kid I used to soak the ground in our back yard to bring the worms up to the surface. Ostensibly I was hunting for fishing bait. In reality it was just a cool preteen boy thing to do on a warm summer evening.

Sometimes I put them into jars. I would drop a handful of dirt on the bottom, and poke holes in the screw-on metal top to allow air into the chamber of captivity. In spite of my precautions most of the inmates died within minutes.

I did the same thing with a lot of other wildlife such as lightning bugs and crickets For a while I puzzled over why I -- not in any sense a collector of things -- did that. Now I wonder where all of the jars that I used came from.

Today I would have to go door-to-door attempting to borrow a suitable receptacle. All we have in our house is one jar of salsa and a few of jelly -- all of them in use. Is the modern quest for universal recyclability at odds with the natural curiosity of sadistic children?

The worms on my driveway however are totally the result of purely natural causes -- four inches of steady rain in forty-eight hours. And they are everywhere. Those that are not above ground on purposeless pilgrimages are just below the surface, ready to pop out at the slightest provocation.

Mars says that she can smell them. It is one of her primary fragrances of spring. I normally have a stronger awareness of the ambient aromas than she does but not in this case. I never totally believed that it was the scent of worms that she detected -- but rather that it was a simple transmigration of the "ick!" factor from her visual sense directly to her nose.


"The earth can smell funny when it rains after a dry spell. The vapor from the ground carries with it a certain bacteria that may be beneficial when inhaled. When the raindrops hit the soil they splash the bacterial spores up and they become airborne, carrying the scent of earth with them. Another smell associated after raining is the smell of earthworms. Like the bacteria in the ground, earthworms only come out when the ground is soaked.

So why does it smell like worms when it rains?

The answer is: Maybe because there are too many of them on the surface to begin with. Another reason is that the same bacteria present in the soil covers the earthworms' bodies. And yet, another reason is that the earth that earthworms have turned during their climb to the surface has released those bacteria spores." (3)

The converse -- "Do worms have a sense of smell?" -- seems less certain. "Worms have specialized chemoreceptors or sense organs ("taste receptors") which react to chemical stimuli. These sense organs are located on the anterior part of the worm." (4) So, do they? Or do they not?

All of which begs the question, how did worms survive evolutionarily when their primary instinct is to stroll around in the meat display case at the precise moment that those who dine on them, the robins, are queuing up at the deli counter?

It is kind of like those tiny sea turtle babies and little penguins whose rite of passage is a death-defying dash to the ocean under the hungry eyes of their predators.

The turtles and penguins have a purpose to their travels, while the worms appear to be just aimlessly wandering around. The higher species also are much, much cuter -- but, at the same time, more endangered. While the lowly worms are totally tricked out sexually.

Ponder that the next time you feel unfocused or unattractive.





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