Brainless Pitcher Plant More Clever Than You Think

Insect-eating pitcher plants found in Borneo may seem brainless, but these carnivorous plants are cleverer than you think, a new study says.

According to a team of UK scientists, who published their research in the journal Proceedings of the Royal Society B, this voracious vegetation has a unique trick up its sleeve that allows it to catch the most insects in its trap as possible - a technique that's nearly as effective as cognitive thinking skills.

"Of course a plant is not clever in the human sense - it cannot plot. However, natural selection is very relentless and will only reward the most successful strategies," biologist Ulrike Bauer of the UK's University of Bristol, who led the study, told Reuters.

The key to its successful insect-trapping abilities comes from the Asian pitcher plant's slippery rim. However, it's only slippery when wet, not when dry. So, during hot and sunny days the plant essentially "switches off" for eight hours given that it's less effective at catching insects in these conditions.

"At first sight, this is puzzling because natural selection should favor traps that catch as many insects as possible," Bauer said in a statement.

However, upon second glance the researchers saw that the plant was onto something - the traps sporadically capture batches of ants that belong to the same species.

To investigate further, Bauer and his colleagues conducted experiments during which they artificially kept the trapping surface wet at all times. They found that the pitcher plants, which are no longer switched off for a length of time during the day, were no longer able to capture large ant batches.

This is because ants, a kind of social insect, rely on scouts to search for food and report back to the colony. When a scout ant finds sweet nectar sitting in a pitcher plant's trap just asking to be eaten, it swiftly goes and tells its friends. But if this carnivorous plant were slippery, it would capture every scout ant that came along, and the larger more appetizing batch of ants wouldn't follow.

"By 'switching off' their traps for part of the day, pitcher plants ensure that scout ants can return safely to the colony and recruit nest-mates to the trap," Bauer explained. "Later, when the pitcher becomes wet, these followers get caught in one sweep. What looks like a disadvantage at first sight, turns out to be a clever strategy to exploit the recruitment behavior of social insects."

How Smart Are Plants Really?

This clever behavior suggests "plant intelligence," or the idea that lush greenery can learn from interacting with its environment, may be real.

Molecular plant scientist Anthony Trewavas, from the University of Edinburgh, recently spoke with Nature World News about various examples of plant intelligence. For example, another type of carnivorous plant, the well-known Venus flytrap, snaps shut its steel-tight "jaws" when its sensitive hairs touch insect prey. (Scroll to read on...)

However, should someone trigger the same reaction using a stick, the trap quickly reopens, the plant sensing that it doesn't have a meal.

In addition, climbing plants known for twisting and winding around tree branches won't do the same around a glass rod. That's because they can't grip the slippery surface, and amazingly once they realize that, they go on their way in search of something else to climb.

"That's an obvious assessment of surface," Trewavas said.

While humans rely on neurons and the brain to think, Trewavas believes plants use chemical changes to demonstrate similar intelligence.

It's difficult to say just how smart plants really are without further research, but clearly they are cleverer than we originally thought.

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