Think your first love makes you squirm? Try being enchanted with nematodes
They say one never truly gets over a first love. Wait! No! Honey, I didn’t mean that. I am completely over what’s-her-name. Honest! I was speaking metaphorically, or something. Really! Listen for just a minute.
What I meant to say is that the first critter I fell in love with when I decided to become a biologist was a nematode. That’s what I did my first research on. I probably spent more years working on nematodes than anything else. Today I just want to talk about them because of those fond memories. It’s sort of like normal people telling about their first cars, or the day they got their ears pierced.
So what’s a nematode? They are tiny round worms that aren’t very much like earthworms at all. Most of them are extremely small, even invisible to the naked eye. They have only longitudinal muscles, so they can’t squeeze themselves thin like earthworms can when you are trying to stab them with a fishhook. Uniquely, each species consists of an identical, small number of cells. They are one of the most diverse of all animals. There may be a million species, but only approximately 30,000 have been identified.
Why? Their obscure size and uniform anatomy makes it difficult to identify individual species. However, half of those identified (about 16,000) have been shown to be parasites, on either animals or plants. They can exist in tremendous numbers. For example a handful of rich, brown topsoil in Iowa can contain hundreds of thousands of worms.
Stephen von Reuss from the Boyce Thompson Institute at Cornell University works with a nematode that can be grown in culture called Caenorhabditis elegans. For various reasons this worm has become a powerful research tool in a number of different areas of study from embryology, cell biology, genetics, behavior and now even communication.
Dr. von Reuss experiments suggest that nematodes use a chemical language to communicate social activities such as reproduction, food location or alarm. Apparently the language consists of molecular messages made of individual chemical fragments that can be put together in various sequences to signal such activities as “party at Larry’s,” “scatter, it’s the heat” and “Hi, what’s your name? My name’s Lyle.”
To identify the language, researchers compared chemicals produced by normal, wild nematodes (nematodes gone wild) with nematodes that had been bred to be chemically mute in various ways. The study indicated that, apparently, the worms combine molecular blocks into simple sentences.
How many words do we really need? Forward, back, right, left, come hither and go away can take care of a lot.
It may sound a little esoteric to spend money deciphering nematode pillow talk, but in this case, their reproductive communications are important.
These animals make up about 80 percent of animal life on Earth, and they can number as many as a million individuals per meter. In fact, I have grown well over a million in one small Petri dish. The fact they make up a huge percentage of parasites of humans, domestic animals and commercial crops makes them medically and economically urgent to understand. They are very difficult to control, and the cost to these industries is enormous.
Learning how nematodes communicate opens up new possibilities for prevention of nematode infections, and control of agricultural situations. I suppose we might even hope that understanding the communication with females at any level could improve men’s lives. Maybe we could just bottle up the various molecules and then mix them according to the message we want to send. Couldn’t be any harder than it already is.
What? Wait! Honey! I didn’t mean … you and I .. You’re easy to … Honey. It’s all my fault. Really. Wait. No. Oh, man! I gotta go.
Gary McCallister is a professor of biology at Colorado Mesa University.