Hornworm caterpillar is a strange insect that consumes tobacco and puffs out nicotine to ward off predators. A group of researchers from the Max Planck Institute for Chemical Ecology in Germany has revealed the tobacco-puffing trait of this very interesting caterpillar. The tactic used by the Hornworm is usually for warding off deadly predators such as the Wolf Spider. Lead researcher Ian Baldwin believes this study is a great way to know how insects defend themselves using the plant they eat.
"It's really a story about how an insect that eats a plant co-opts the plant for its own defence," said Ian Baldwin, professor at the Max Planck Institute for Chemical Ecology in Germany.
The plan here is to know which genes get activated when the caterpillar consumes nicotine from tobacco plants. The defensive tactics of caterpillars is known as "defensive halitosis". During the study, researchers fed a caterpillar that ate tobacco prior to facing a wolf spider. Interestingly enough, the wolf spider was unable to eat the insect due to the nicotine fumes it releases from its spiracles (tiny pores on its side). However, when the same spider is fed a caterpillar that ate a gene altered tobacco plant, the spider quickly attacked and killed it.
Basically, the researchers targeted the gene inside the caterpillar that allows it to turn on its defensive mechanism, and forcefully deactivate it.
Additionally, if you're wondering how caterpillars are able to consume tobacco plants, without being poisoned, that's because caterpillars are 100 times more resistant to nicotine when compared to humans. This could be due to the differences in biology, or maybe something else is at work.
Baldwin also explains why it is best to observe animals from within their natural habitat instead of a lab, since if he and his team had done the latter, they may never have come across this extraordinary behavior.
"We never would have discovered the function of this gene if the spider hadn't told us," he told LiveScience.
Bear in mind that the nicotine defense mechanism only seems to work against wolf spiders. Other predators are immune to the Hornworm caterpillar's tobacco-filled breath.