It’s a twist of fate that wouldn’t feel out of place in a horror movie: A platoon of caterpillars, young and hungry, descend on a defenseless tomato plant to feast, but as they begin to eat something goes terribly wrong. The leaves no longer satisfy, and they turn on each other in a cannibalistic frenzy — feeding wildly until just one, sated and content, remains.
In the case of the tomato plants, they’re simply exploiting a weakness that already exists in their enemy. When under attack they release a compound known as methyl jasmonate that both signals other plants in the vicinity to be on guard and gives their leaves a noxious taste. Caterpillars are known to turn on each other for sustenance when the going gets rough, and by making themselves unpalatable, the tomato plants encourage this behavior.
Cannibalistic caterpillars and proactive plants have been documented for some time, but it wasn’t until now that a researcher put the two together. John Orrock, a researcher at the University of Wisconsin-Madison sprayed tomato plants with varying concentrations of methyl jasmonate and put them in containers with beet armyworms, a common agricultural pest. The more of the compound each plant had been doused with, the quicker the caterpillars turned to cannibalism. Control plants, on the other hand, weren’t able to mount a defense quickly enough and their leaves were totally eaten. On those plants, the caterpillars lived in harmony with one another, spared the gruesome fate of their hungry counterparts.
The plants’ actions work on two levels: they keep the caterpillars away from their leaves, and they reduce the total number of caterpillars as well. The strategy isn’t totally effective, because some caterpillars survive and those that do are typically exceptionally well-fed and more likely to survive. The study was published Monday in the journal Nature Ecology and Evolution.
Orrock hopes that his findings will lead to new strategies for pest control in agriculture, and says that they could elucidate some of the ways that pathogens move through insect populations.
so can we think of strategies that use "yucky tasting stuff" instead of pesticides to controlled bugs?
this would reduce the "collateral damage" to beneficials who might be in the area
maybe stressing out a tomato plant to sacrifice it to a blender
to use as a spray on the other tomato plants (and potatoes?)
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