The carnivorous pitcher plants are known for enticing their prey by secreting sweet nectar from their rims. Once the unsuspecting insect is trapped inside the plant's unique pitcher-shaped leaves, the slippery inner surfaces ensure that it slides straight down into the digestive juices that lie at the bottom. Now, scientists have discovered that one crafty species has conjured up an additional trick up its lid.
The study led by Cambridge University's Department of Plant Sciences professor, Dr. Ulrike Bauer, began accidently. While observing a beetle seeking shelter under the lid of the Nepenthes gracilis, a pitcher plant native to South East Asia, the biologist noticed that though the insect avoided getting wet, it ended up becoming a tasty meal for the crafty plant. Since they had previously observed little ants strolling in and out of the plant when it was dry, they began to wonder if the beetle's sad end may have had something to do with the rain.
To test if this theory had any merit, they simulated raindrops by fitting one of the plants with a hospital drip and recording the fate of a colony of captive ants that were foraging for nectar under the pitcher's lid. They noticed that while the ants were fine before and right after the 'rain', about 40% of the population succumbed to the plant, when the lid was wet.
When they examined the lower lid surface of the pitcher, they noticed that it was covered with specialized wax crystals - Ones that provided just the right amount of traction for the little ants when it was dry. As soon as the lid became moist, it turned into a slippery slope, dropping the insect right into the digestive juices. What is even more interesting is that in order to take advantage of this unique feature, the plant secrets larger amounts of attractive nectar under its lid when compared to other plants from the same family.
Dr. Bauer, who released the team's findings in a research report earlier this month, said that what fascinated her the most about this was though scientists have been unraveling the mysteries of the pitcher plant since Charles Darwin first wrote about them in 1875, they were still, discovering new trapping techniques.
This is not the only pitcher plant species has developed a unique survival skill. The Nepenthes bicalcarata that are also native to the jungles of Borneo have forged a unique partnership with tiny carpenter ants that are allowed to live inside the stem and feed off its nectar. In return, the ants are responsible for a number of things. They keep the mouth of the pitcher clean so that it is smooth and slippery at all times and also stand guard to prevent victims from getting away. They also attack weevils that love munching on the pitcher plant, but most important of all, they carry off the remains of any large prey that the pitcher has been unable to digest. If the debris is allowed to accumulate, it would rot and impede the plant's ability to digest and assimilate nutrients, which could eventually lead to its death - Pretty amazing isn't it?
Resources: Cambridge-news.co.uk, cbc.ca, Dailymail.co.uk