Cannibals – they're straight out of a horror movie, right? Wrong. They're in your backyard garden. Yes, there are cannibals running amok in your garden at this very moment. Specifically, there are cannibals that used to try to eat your garden, but your produce got fed up and turned their predators on themselves. Scientists recently discovered certain insects that feed on garden tomatoes are turning on themselves and becoming cannibals.
Why? These tomatoes are turning naturally made chemicals, which typically deter insects from eating them, into a substance that makes their consumers eat one another. Yes, tomatoes are turning insects into cannibals. Insects are now eating themselves – and not the tomatoes – thanks to a defense system meant to ward off herbivores. These smart plants are fighting against insects in one of the craziest (and possibly smartest) ways ever.
The Chemicals Tomatoes Use To Dissuade Insects From Eating Them Are Making Insects Eat Themselves
Tomatoes produce chemicals meant to deter herbivores from eating them. These chemicals act as a sort of "alarm signal," and tomatoes typically release them when they sense an insect is eating them. Usually, these are caterpillars. These nasty substances signal to insects this isn't a good thing to eat, and they usually leave it alone.
But a new study from the University of Wisconsin show that not only are these chemicals deterring insects from eating tomatoes, but they're also sending another huge signal to them. Instead of eating the tomatoes, they get a hunger for one another. Tomatoes that release a higher amount of these chemicals influence more insects to eat their own kind.
Plants That Emit More Chemicals Have Five Times More Biomass Than Those That Don't
For this particular experiment, scientists took the naturally occurring chemicals plants make and sprayed more of them on plants. The plants that had the most chemicals – also called "well-defended plants" – were larger in size than their other counterparts, and they also warded off a higher number of bugs (unsurprisingly). In addition, they created more cannibals than the lesser-defended plants.
Though, in a shocking twist, the lesser-defended plants also created a high number of cannibal caterpillars. But only if the caterpillars were allowed to eat on the plant until it was completely finished. When the plant was almost completely devoured, the caterpillars would turn on themselves in a high number.
Cannibalism Is Actually Sort Of Common In Herbivores
While most people associate cannibalism with carnivores, it's actually more common than you might think that herbivores eat their own. In particular, bugs that only eat plants are susceptible to becoming cannibals because of plant defense systems. There are several types of plants – including tomatoes – that will release a chemical turning their attackers against one another. These plants affect caterpillars more than any other type of bug, but other plant feeders have turned to cannibalism after having a nibble.