Saturday, November 17, 2012

Looking for shelter, ending up as food

During rainstorms, insects like ants and beetles will often take refuge under the lid of the slender pitcher-plant (Nepenthes gracilis). But raindrops crashing on the lids of the pitcher-plant make them lose their footing (they walk upside down on the underside of the lid) and they fall straight into the pool of digestive fluids at the bottom.

"Scientists h
ave 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!" said Dr. Ulrike Bauer from the University of Cambridge's Department of Plant Sciences, who is the lead author of the paper (Source 1).

The lower lid surface is covered with highly specialised wax crystals which gives it just the right level of slipperiness to enable insects to walk on the surface under normal and calm conditions but lose their footing when the lid is disturbed, which in most cases, will be due to rain drops. Further, the lid of N. gracilis secretes larger amounts of attractive nectar than that of other pitcher plants.

To test this idea, the researchers studied a captive colony of ants that was foraging on the nectar under the lid and simulated 'rain' with a hospital drip. And although ants can normally cling to the lid, it was found that falling drops can knock off 40% of them. And when Dr. Bauer coated the lids with an “anti-slip” silicon polymer, only 25% of the ants were flicked off.

Source:
1) Published: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0038951
2) http://www.dogonews.com/2012/6/18/crafty-pitcher-plant-species-uses-rain-to-snags-its-prey
3) http://www.cam.ac.uk/research/news/pitcher-plant-uses-rain-drops-to-capture-prey/
4) http://www.dailymail.co.uk/sciencetech/article-2159163/When-rains-feeds-The-pitcher-plant-uses-power-water-droplets-catapult-ants-death.html
5) http://phys.org/news/2012-06-pitcher-power-prey.html

Image: N. gracilis pitcher with a visiting Polyrhachis pruinosa ant.

Credit: From: Bauer U, Di Giusto B, Skepper J, Grafe TU, Federle W (2012) With a Flick of the Lid: A Novel Trapping Mechanism in Nepenthes gracilis Pitcher Plants.

PLoS ONE 7(6): e38951. doi:10.1371/journal.pone.0038951
Looking for shelter, ending up as food

During rainstorms, insects like ants and beetles will often take refuge under the lid of the slender pitcher-plant (Nepenthes gracilis). But raindrops crashing on the lids of the pitcher-plant make them lose their footing (they walk upside down on the underside of the lid) and they fall straight into the pool of digestive fluids at the bottom.

"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!" said Dr. Ulrike Bauer from the University of Cambridge's Department of Plant Sciences, who is the lead author of the paper (Source 1).

The lower lid surface is covered with highly specialised wax crystals which gives it just the right level of slipperiness to enable insects to walk on the surface under normal and calm conditions but lose their footing when the lid is disturbed, which in most cases, will be due to rain drops. Further, the lid of N. gracilis secretes larger amounts of attractive nectar than that of other pitcher plants.

To test this idea, the researchers studied a captive colony of ants that was foraging on the nectar under the lid and simulated 'rain' with a hospital drip. And although ants can normally cling to the lid, it was found that falling drops can knock off 40% of them. And when Dr. Bauer coated the lids with an “anti-slip” silicon polymer, only 25% of the ants were flicked off.

Source:
1) Published: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0038951
2) http://www.dogonews.com/2012/6/18/crafty-pitcher-plant-species-uses-rain-to-snags-its-prey
3) http://www.cam.ac.uk/research/news/pitcher-plant-uses-rain-drops-to-capture-prey/
4) http://www.dailymail.co.uk/sciencetech/article-2159163/When-rains-feeds-The-pitcher-plant-uses-power-water-droplets-catapult-ants-death.html
5) http://phys.org/news/2012-06-pitcher-power-prey.html

Image: N. gracilis pitcher with a visiting Polyrhachis pruinosa ant. 

Credit: From: Bauer U, Di Giusto B, Skepper J, Grafe TU, Federle W (2012) With a Flick of the Lid: A Novel Trapping Mechanism in Nepenthes gracilis Pitcher Plants. 

PLoS ONE 7(6): e38951. doi:10.1371/journal.pone.0038951

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