During heavy rain, the lid of Nepenthes gracilis pitchers acts like a springboard, catapulting insects that seek shelter on its underside directly into the fluid-filled pitcher, new research has found. The findings were published today, Wednesday 13 June, in the journal PLoS ONE.
Pitcher plants (Nepenthes) rely on insects as a source of nutrients, enabling them to colonise nutrient-poor habitats where other plants struggle to grow. Prey is captured in specialised pitcher-shaped leaves with slippery surfaces on the upper rim and inner wall, and drowns in the digestive fluid at the bottom. Under humid conditions, the wettable pitcher rim is covered by a very thin, continuous film of water. If an insect tries to walk on the wet surface, its adhesive pads (the 'soles' of its feet) are prevented from making contact with the surface and instead slip on the water layer, similar to the 'aquaplaning' effect of a car tire on a wet road.
However, researchers have now discovered a new, unique method of capturing insects by the pitcher plant Nepenthes gracilis.
The lead author of the paper, Dr Ulrike Bauer from the University of Cambridge's Department of Plant Sciences, said: "It all started with the observation of a beetle seeking shelter under a N. gracilis lid during a tropical rainstorm. Instead of finding a safe - and dry - place to rest, the beetle ended up in the pitcher fluid, captured by the plant. We had observed ants crawling under the lid without difficulty many times before, so we assumed that the rain played a role, maybe causing the lid to vibrate and 'catapulting' the beetle into the trap, similar to the springboard at a swimming pool."
To test their hypothesis, the scientists simulated 'rain' with a hospital drip and recorded its effect on a captive colony of ants that was foraging on the nectar under the lid. They counted the number of ants that fell from the lid in relation to the total number of visitors. They found that ants were safe before and directly after the 'rain', but when the drip was switched on about 40% of the ants got trapped.
Further research revealed that the lower lid surface of the N. gracilis pitcher is covered with highly specialised wax crystals. This structure seems to provide just the right level of slipperiness to enable insects to walk on the surface under 'calm' conditions but lose their footing when the lid is disturbed (in most cases, by rain drops). The scientists also found that the lid of N. gracilis secretes larger amounts of attractive nectar than that of other pitcher plants, presumably to take advantage of this unique mechanism.
Dr Bauer added: "Scientists have tried to unravel the mysteries of these plants since the days of Charles Darwin. The fact that we keep discovering new trapping mechanisms in the 21st century makes me curious what other surprises these amazing plants might still have in store!"
University of Cambridge: http://www.cam.ac.uk
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
Algorithms developed by Google designed to encode thoughts, could lead to computers with ‘common sense’ within a decade, says leading AI scientist
New fossil evidence suggests dogs emerged as a separate species from wolves far earlier than scientists previously believed
Researchers discover the 425-million-year-old remains of a new species of parasite - still clamped to the host animal it invaded.
It should be raptor egg blue instead of robin egg blue. Some modern birds lay colourful eggs, but now we know it's a trick their dinosaur ancestors used too
WASHINGTON (Reuters) - Scientists on Thursday unveiled the most comprehensive analysis ever undertaken of the world's ocean plankton, the tiny organisms that serve as food for marine creatures such as the blue whale, but also provide half the oxygen we breathe.
Scientists on Thursday unveiled the most comprehensive analysis ever undertaken of the world's ocean plankton, the tiny organisms that serve as food for marine creatures such as the blue whale, but also provide half the oxygen we breathe.
Researchers say they're excited about a new brain implant that allowed a paralyzed patient to control a robotic arm with his mind. Erik Sorto is the first in the world to have this new neural prosthetic device. Elaine Quijano reports.
Genetically, at least, not that much has changed in the billion years since you two last shared a relative. Roughly half the 500 genes yeast need for life are interchangeable with the human versions.
What controls aging? Biochemist Cynthia Kenyon has found a genetic mutation that can more than double the lifespan of a tiny worm, which points to how we might one day significantly extend human life.
Java sparrows amp up their tunes with acoustic beak taps synchronized with chirps