Most plants are sweet, sunlight-chugging citizens. These carnivorous kingpins are not.
Nepenthes bicalcarata – carnivorous kingpins
You know a pitcher plant when you see one. Marked by vicious-looking “pitfall traps” rimmed by a slippery surface and filled with a fluid that drowns and dissolves insects, the plants are unmistakable killers. In fact, their fearsome physiques make pitcher plants the poster children for carnivorous flora. But one pitcher seems to be the black sheep of the genus. The Nepenthes bicalcarata lacks the slippery walls needed to capture and contain prey, and its digestive fluids aren’t nearly as acidic as its cousins’.
While that may seem like a disadvantage, the plant gets plenty of help from its friends. Small groups of Camponotus schmitzi ants reside in the swollen tendrils at the base of the plant’s pitcher. In exchange for room and board (nectar secreted from the pitcher rim and a few bites of anything caught), the ants roll up their sleeves and get to work.
Green Beans – assassins that lurk
When a Canadian study revealed that pine trees were cutting nefarious deals with a local fungus, using it to kill insects and harvest nutrients in exchange for carbon, researchers wondered whether other plants were making similar pacts. To test the theory, the scientists set up a devious experiment using the genus Metarhizium, killer fungi that infect more than 200 species of insects by eating the bugs from the inside out.
Two weeks later, all the larvae were dead, and N-15 accounted for a quarter to a third of the nitrogen in the beans. There was only one way the plants could have gotten the nitrogen: The fungus had killed the insects and transferred the nutrients to the plants on the other side of the screen. Since Metarhizium fungi live in and around plant roots all over the world, it’s likely that the cold-blooded green beans aren’t the only plants secretly using the fungal hit men to supply them with meat.
Roridula gorgonias – eater
It took more than a century of scientific back-and-forth, but in 1996, South African researchers finally proved that R. gorgonias was a flesh eater (at least indirectly) by shaking down its partner in crime, Pameridea roridulae. The tiny bug lives exclusively in the leaves of R. gorgonias, and it’s built to thrive in that environment. Its body is covered in a grease that keeps it from getting stuck in the plants resin, and it feeds on any insects that get trapped. While this carrion bug seems to be stealing the plant’s captives, it’s actually sharing the feast by acting as an external stomach. After devouring the trapped insects, the P. roridulae excretes onto those same leaves. With all the digestive heavy lifting completed, the plant can absorb some predigested nitrogen and other nutrients. Seems like a fair trade for putting up with the bug’s crap! – By Matt Soniak