An insect-eating plant of Borneo is proving more intelligent that its pitcher-plant folks by exploiting changes in weather conditions to attract only batches of ants or other insects into its leaf traps where they are consumed. The intelligence of this pitcher plant lies in the fact that ignores individual ants that strays to its nectar – but awaits the arrival of informed batches of ants before closing in to munch on them.
Based on natural weather fluctuations, this Asian pitcher plant – so-called because of its pitcher-like, liquid-filled, funnel-shaped leaves – modifies its insect-catching abilities in response to environmental conditions. Given the right weather conditions on hot, sunny afternoons, it switches on its trapping powers to entrap batches of nectar-eating insects, and on cold days it switches off its trap.
“The plant’s key trapping surface is extremely slippery when wet, but not when dry,” said Ulrike Bauer, a biologist from Bristol University’s School of Biological Sciences. “For up to eight hours during dry days, these traps are ‘switched off’ and do not capture any of their insect visitors.”
The point here is that during the right weather conditions, this plant allows any scouting ant to come to its nectar and have its fill; but by the time the scout goes back to inform its colony or batch of the location of the plant’s nectar, the pitcher would have activated its leaves to be both wet and slippery with the readiness to snap shut when triggered. The unsuspecting scout ant leads its folks back to the nectar and as soon as the plant senses that a batch of ants are crowding into its nectar, the leaves get very wet and slippery for the ants to beat a hasty retreat – and the next thing they feel is the leaves closing in on them to make a mincemeat of their sorry selves.
“To control when its trap is slippery, the pitcher plant secretes sugary nectar that primes the trapping surface to become wet through condensation at lower humidity levels than other plant surfaces. That activates the trap during afternoons when many day-active insects are still out and about,” said Bauer.
“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,” the researcher said. “What looks like a disadvantage at first sight, turns out to be a clever strategy to exploit the recruitment behavior of social insects.”