Pitcher plants are basically lazy trap-makers. They turn their leaves into deep, slippery cups filled with rainwater laced with digestive enzymes. Sweet nectar around the rim attracts insects. Once a visitor steps on the edge, the waxy inner walls make sure it slides straight down and can’t climb back out.
Inside, the prey drowns and slowly gets dissolved, releasing the nitrogen and minerals the plant needs. Pitchers come in all sizes, from tiny thumb-sized traps in North American bogs to monsters over 30 centimetres tall in Southeast Asian rainforests.
The world champion is Nepenthes rajah from Borneo, which can hold over three litres of liquid. Researchers have occasionally found tree shrews and even small rats dissolved at the bottom. Mostly though, rajah works as a luxury toilet for shrews that come to lick its sugary lid - their droppings provide most of the nutrients.
