The Nepenthes bicalcurata Hooker [ne pen' thees bi cal' coo ra ta] is a wonderfully wicked-looking trap for insects and for plant collectors. This twin-spurred insectivorous vine hails from the rainforests of Borneo. It is a complex plant, both in its own physiology and the role it fills in the ecosystem.

Nepenthes have uniquely adapted leaves. The lamina (leaf blade) carries on photosynthesis as any ordinary leaf. The midvein of the leaf extends into a tendril. If this tendril comes into contact with other vines or stems, it will wrap around that object for support. The end of the tendril develops into a fluid-filled ascidium (pitcher). The fluids in Nepenthes contain chitinase, proteases, a wetting agent, and an insect tranquilizer. Nectar is produced under the operculum (lid) and along the peristome (lip) to lure insects.

The ascidia of the N. bicalcurata have what appear to be two fangs under the opercula. On humid mornings, these fangs often drip with nectar. Insects coming in for a feast will find plenty of food, but little footing. The greedy are easily seduced into overextending their reach and fall into the death trap. (Hmm, is there a moral here?)

But not all insects fall prey to the N. bicalcurata. This Nepenthes has a unique relationship with ants of the genus Colobopsis. These ants are not interested in sugars; they prefer to prey on other insects. The Nepenthes is already attracting the prey for the ants, but goes a step further. The tendril is hollow and provides a home for the ants.

Nepenthes receive nutrients from the digestion of insects that have fallen into the ascidia. But the N. bicalcurata is extremely efficient at luring and trapping. It often collects too many insects. The insects in overloaded traps start to decompose and the bacterial action fouls the digestive fluids. The bacteria damage and eventually destroy the ascidium. The loss of an ascidium drains the resources of the plant. To replace a pitcher, the Nepenthes has to grow a new leaf, tendril, trap, and equip it with all the enzymes and sugars to function.

Colobopsis ants have adapted to life with Nepenthes bicalcurata. These ants have 'learned' to swim in the fluid designed to tranquilize, drown, and digest insects. They also climb the slippery sides of the pitcher where other insects fall. Colobopsis ants remove excess and large insects, preventing bacterial rot and the early loss of the ascidia. It is not often found in nature that two very different predators with the same prey, not only co-exist, but actually benefit each other.