Caterpillar smoker’s breath

By on January 8, 2014

An estimated 43.8 million Americans are smokers. Everywhere today, one may see a designated area for smokers so that those toxic fumes do not bother the rest of the population. However, those noxious fumes that non-smokers try to avoid are actually used as a defense for the tobacco hornworm caterpillar.

“I think it’s actually the first example of using bad breath as a defense, although I’m sure that everybody has had a personal encounter of something similar,” says Ian Baldwin of the Max Planck Institute for Chemical Ecology in Jena, Germany.

Consider the experience of walking up to someone that has just smoked a cigarette and them breathing into your face. Many people will think of this as unpleasant and decide to go in the opposite direction or offer them some gum. The tobacco hornworm caterpillar takes the poisoning from the tobacco plant and produces toxic halitosis or in simpler terms, bad breath. It has a specific gene that allows the nicotine to be diverted to the insect equivalent of a bloodstream and thus make the “smoker’s breath” that is capable of scaring off the caterpillar’s potential predators.

However, while the nicotine in tobacco is considered a stimulant in humans, it has the opposite effect on the caterpillars. The caterpillars become sluggish, but this side effect is a small price to pay for something that can save its life. Through the researcher’s experiments, they took tobacco hornworm caterpillars that had eaten tobacco and other caterpillars that do not eat tobacco and then placed a wolf spider in with the caterpillars. The caterpillars that had ingested tobacco were left alone due to their bad breath while those that had not were ingested themselves. Those same putrid fumes that scare off some people are used by this caterpillar as a form of defense.

“Caterpillar smoker’s breath is a new basic insight into an insect that chemical ecologists have been studying for so long that it should be ‘depressingly familiar,” says entomologist May Berenbaum of the University of Illinois at Urbana-Champaign. And the new insight “would never have been uncovered in just the lab environment.”

By studying the caterpillars in their native environments, researchers were able to actually see how they use the tobacco. An interesting fact that they have discovered is that the caterpillars only use about 65% of the nicotine they ingest which raises the question of where the other percentage goes.

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About Samuel Wainwright

Samuel Wainwright is the Features Editor at the Kaleidoscope. He is a double major in English and History with a double minor in Psychology and High School Education and a Pre-Law indicator.
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