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Worm Language

Worm Language Sheath Nematode (Hemicycliophora spp.)
Photo Credit: California Department of Food and Agriculture

Nematode worms have a surprisingly complex communication system.


Transcript

Worm linguistics. I’m Bob Hirshon and this is Science Update.

They may not be literary giants, but small roundworms called nematodes have a surprisingly rich language all their own. As Cornell University chemical biologist Frank Schroeder explains, the worms communicate using chemical signals. His team found it’s not just the chemicals themselves, but how they’re combined, that determines the message.

Schroeder:
They have their own grammar, if you want. And certain combinations of chemical "words" mean similar things, and other combinations mean different things.

For example, a signal composed of two chemical building blocks tells nearby worms to go away. But adding a third chemical makes other worms gather ’round instead. The worms may use the signals to exploit resources and avoid threats. Schroeder says that if we can manipulate these signals, it may help control nematode crop pests, or parasitic worms that infect people. I’m Bob Hirshon for AAAS, the Science Society.


Making Sense of the Research

In human language, sequence and combination matter. The English alphabet, for example, has only 26 letters, which can be arranged into hundreds of thousands of words. Move just one letter in the word “words” from the back to the front, and you end up with “sword,” something completely different.  And on the level of sentences, “Jill ate the chicken” means something very different from “The chicken ate Jill.”  Yet those sentences use the same four words. 

Imagine how complicated our language would be if every word had to have its own unique symbol. You can get some sense of that from Asian languages; written Mandarin Chinese, for example, uses tens of thousands of picture-like characters. However, these characters mostly represent syllables, and still get combined and rearranged in order to form words. Combining and arranging letters or characters allows us to convey many different ideas from a limited set of elements. (Consider that Shakespeare's Hamlet and the users' manual for an mp3 player are made from the same 26 letters!)

Scientists already knew that nematodes communicate with each other using chemical signals. This study, however, found that those chemicals have their own syntax, or rules for arranging elements into different meanings. In other words, the worms don't just use one chemical for each possible message. They combine two, three, or more chemicals at a time, and each combination has a different meaning, just like letters and words. 

The researchers have only just begun to identify what these messages are. As you heard, adding one more chemical to the signal for “go away” changes the meaning to “come here.” It's still unknown how big the worms' “alphabet” of signaling chemicals is, or how many different chemicals may be used in a single message. It's clear, though, that worm language may be extremely different from ours, but it's built on one similar principle, which is that it's better to rearrange a smaller set of signals than to come up with a new signal for everything you want to say.

Now try and answer these questions:

  1. How do nematodes communicate?
  2. What does this work add to our understanding of worm language?
  3. In what way is the worm language like human language?
  4. From the worm's point of view, why might it be biologically useful to create different meanings by combining signaling chemicals in different ways?

You may want to check out these related podcasts:

The Science Updates Eavesdropping Plants and Atmospheric Aspirin delve into the little-known world of plant communication.

The Science Update Human Language looks at what sets our language apart from other species'.


Going Further


For Educators

The Science Update lessons Eavesdropping Plants and Atmospheric Aspirin delve into the little-known world of plant communication.

The Science Update Human Language looks at what sets our language apart from other species'.


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