The viscoelastic flytrap

Fly killer

Nepenthes are cruel carnivorous plants from the Asian tropics that eat any crittur unlucky enough to fall into the digestive juices they secret inside their bowl-shaped petals. It’s a slow sticky death in which the insect slowly dissolves while a-strugglin’ and a-scramblin’ to get out.

But exactly how the plants trap their prey has puzzled biobods. Many species of Nepenthes have slippery surfaces which prevents insects from getting any purchase as they fight their way out. But other plants lack this adaptation and yet still trap their prey.

Now Laurence Gaume  and Yoel Forterre at the Universite de Provence in Marseille, reckon they’ve hit on the answer. They say that the digestive juices themselves play a crucial role. They worked it out by studying the  species N. rafflesiana and  “…by comparing retention of insects thrown into glass vials filled with water or pure digestive fluid. “

After measuring the properties of the liquid such as its viscosity, elasticity surface tension etc they say:  “our study unveils the peculiar viscoelastic properties of the digestive fluid of N. rafflesiana and its crucial role in prey capture.”

In other words the digestive juices are so sticky and stretchy that insects cannot climb out, something that nobody has noticed before, apparently.

The pair suggest that the juices could be used a new type of pest control in which the liquid both traps and kills insects. Who woulda thought?
Ref: arxiv.org/abs/0711.4724: A Viscoelastic Deadly Fluid in Carnivorous Pitcher Plants

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