Plantwatch: Venus flytrap has ‘fire alarm’ to detect blaze danger

Trigger hairs that close its trap contain heat-sensitive cells that react to a rapid temperature rise

A fire alarm" has been discovered in a plant. The Venus flytrap is renowned for its carnivorous trap that snaps shut on unsuspecting insects - when the prey touches sensitive trigger hairs an electrical signal is fired across the trap, and two signals in quick succession close the trap in a fraction of a second.

But heat-sensitive cells have also been found in the trigger hairs, acting as a fire alarm. The flytrap grows in grassy swamps in North Carolina in the US, where the grass often dries up and can be set alight by lightning, threatening the plant with serious burns.