Читать книгу Extreme Nature - Mark Carwardine - Страница 23

NAME	pitcher plants Nepenthes species
LOCATION	South-east Asia
ABILITY	catching prey in slippery, deadly pitchers

© Mark Moffett/Minden Pictures/FLPA

There are many different species of pitcher plant, but all are insect-traps with the slipperiest of sides, providing extra nitrogen (from insect corpses) to help the plants flower and set seed. Among the most sophisticated are the leaves of vine-like Nepenthes. Each of these pitfall traps has an ‘umbrella’ lid and a base partly filled with a soup of digestive enzymes. The lure may be colour (usually red), smell (nectar or, later, rotting corpses) or tasty hairs. When an insect lands on the rim, it slips into the deadly broth, possibly intoxicated by narcotic nectar.

Slipperiness is achieved in two ways, perhaps depending on what insects are likely to be attracted (walking insects if the Nepenthes is on the ground or flying insects if it is up in the tree canopy). The inner walls are usually impossible to climb, being covered with slippery waxy platelets. Others go a stage further and have a surface that attracts a film of water which aquaplanes the insects to their death. Some also use trickery. When their pitchers are dry, ants are lured by the nectar, and don’t slip, and so go and tell more ants about the find. If the surface is wet when they return, they all fall in.

Another of the Nepenthes species is in partnership with an ant that has specialised feet, allowing it to get in and out of the pitcher to retrieve corpses. It eats these and drops the remains and its faeces into the pitcher, so speeding up the release of nitrogen for its predatory host to ingest.