New study finds plants have the power to turn caterpillars into cannibals

Plants have a sneaky and sadistic trick to prevent caterpillars from munching on their leaves, a new study published Monday in the journal Nature Ecology and Evolution revealed. Researchers have discovered that plants secrete a chemical that makes them taste less delicious, leaving herbivorous caterpillars with the tough choice of eating less appealing foliage — or each other.
Caterpillars sometimes choose cannibalism. "When the chips are down, eating another caterpillar may not be a bad decision, [and] it turns out that the chips can be down if you find yourself on a plant that is heavily defended," said John Orrock, a co-author of the research.
The researchers tested this phenomenon by coating tomato plants in four different sprays — one containing only detergent and the others containing different amounts of methyl jasmonate, the substance given off by plants — and then siccing eight beet armyworm caterpillars on the plants:
The Week
Escape your echo chamber. Get the facts behind the news, plus analysis from multiple perspectives.

Sign up for The Week's Free Newsletters
From our morning news briefing to a weekly Good News Newsletter, get the best of The Week delivered directly to your inbox.
From our morning news briefing to a weekly Good News Newsletter, get the best of The Week delivered directly to your inbox.
After 52 hours, about 7 percent of caterpillars were cannibalised on leaves sprayed with either no methyl jasmonate or the lowest concentration, while around 16 percent of caterpillars had been eaten on leaves sprayed with either of the more concentrated methyl jasmonate sprays.Most revealing was that more than five times as much plant matter was left on plants sprayed with the highest concentration of methyl jasmonate compared to those sprayed only with detergent — the latter were almost completely stripped of leaves. [The Guardian]
Orrock said that while scientists knew herbivores "were sensitive to plant defenses," they didn't realize that plants' defenses might cause herbivores to make "the choice of eating another herbivore." "From the plant defense perspective, making yourself so nasty that you are suddenly not the best thing on the menu works pretty well," Orrock said.
A free daily email with the biggest news stories of the day – and the best features from TheWeek.com
-
September 1 editorial cartoons
Cartoons Monday’s political cartoons include Labor Day picnic, branding strategy, and more
-
What is Tony Blair's plan for Gaza?
Today's Big Question Former PM has reportedly been putting together a post-war strategy 'for the past several months'
-
When does autumn begin?
The Explainer The UK is experiencing a 'false autumn', as climate change shifts seasonal weather patterns
-
Russian strike on Kyiv kills 23, hits EU offices
Speed Read The strike was the second-largest since Russia invaded in 2022
-
UN votes to end Lebanon peacekeeping mission
Speed Read The Trump administration considers the UN's Interim Force in Lebanon (UNIFIL) to be a 'waste of money'
-
Israeli double strike on Gaza hospital kills 20
Speed Read The dead include five journalists who worked for The Associated Press, Reuters and Al Jazeera
-
China is silently expanding its influence in American cities
Under the Radar New York City and San Francisco, among others, have reportedly been targeted
-
Kyiv marks independence as Russia downplays peace
Speed Read President Vladimir Putin has no plans to meet with Zelenskyy for peace talks pushed by President Donald Trump
-
Trump halts Gaza visas as Israelis protest war
Speed Read Laura Loomer voiced her concerns over injured Palestinian kids being brought to the US for treatment and a potential 'Islamic invasion'
-
Russia tries Ukraine land grab before Trump summit
Speed Read The incursion may be part of Putin's efforts to boost his bargaining position
-
US, China extend trade war truce for 90 days
Speed Read The triple-digit tariff threat is postponed for another three months