Crafty carnivorous Pitcher plants!
By zteve t evans
Plants have no brains but for an organism that lacks such a commodity some of them have evolved some remarkable ways to ensure their own survival. For example the carnivorous Raffles' Pitcher plant, (Nepenthes rafflesiana), of Borneo, named after Stamford Raffles, has been discovered employing a clever tactic to trap the ants and insects that it feeds upon.
There are several species of carnivorous pitcher plants that have evolved specialized leaves that they use to trap their prey. These leaves are known as pitfall traps. These traps are cup-like with steep sloping sides and contain a liquid that attracts flies, ants and other insects. They use bright colors, smells, and nectar to entice the victim into a deadly trap.
There are several species of carnivorous pitcher plants that have evolved specialized leaves that they use to trap their prey. These leaves are known as pitfall traps. These traps are cup-like with steep sloping sides and contain a liquid that attracts flies, ants and other insects. They use bright colors, smells, and nectar to entice the victim into a deadly trap.
Clever tactics
Research has shown that appears to show remarkable planning abilities in trapping its prey which is predominantly ants. They seem to have the ability to turn off their traps for long periods of time. This allows a number of scout ants or insects to enter the trap and escape. These scouts then return to their nests or colonies with the news of where food can be found for others to return to the trap with the prospect of a good food supply. This is a crafty tactic that will bring more ants to the trap that the plant will catch and feed on.
In fact what is happening is the result of a long process of natural selection that has evolved a pitcher plant that has developed the remarkable ability to take advantage of the behavior of their prey especially ants and also the local humidity and weather conditions.
Ants find food by sending out "scout" ants to seek an appropriate resource. When the scout finds a resource they return to the nest leaving a trail of scent. On return to the nest the information is passed on to other scouts who follow the the trail back to the resource which in this case is a pitcher plant. When they return they reinforce the trail and again pass the information on to other scouts who follow the trail to the pitcher plant. Rather than the capture of just one ant this technique can lead to the capture of a batch of victims when the trap is activated. While the pitcher plant trap is not active in dry conditions if it rains or humidity increases the trap is activated and the sides of the pitcher become slippery. This gives a greater chance of catching a batch of ants rather than just the original scout ant.
Research has shown that appears to show remarkable planning abilities in trapping its prey which is predominantly ants. They seem to have the ability to turn off their traps for long periods of time. This allows a number of scout ants or insects to enter the trap and escape. These scouts then return to their nests or colonies with the news of where food can be found for others to return to the trap with the prospect of a good food supply. This is a crafty tactic that will bring more ants to the trap that the plant will catch and feed on.
In fact what is happening is the result of a long process of natural selection that has evolved a pitcher plant that has developed the remarkable ability to take advantage of the behavior of their prey especially ants and also the local humidity and weather conditions.
Ants find food by sending out "scout" ants to seek an appropriate resource. When the scout finds a resource they return to the nest leaving a trail of scent. On return to the nest the information is passed on to other scouts who follow the the trail back to the resource which in this case is a pitcher plant. When they return they reinforce the trail and again pass the information on to other scouts who follow the trail to the pitcher plant. Rather than the capture of just one ant this technique can lead to the capture of a batch of victims when the trap is activated. While the pitcher plant trap is not active in dry conditions if it rains or humidity increases the trap is activated and the sides of the pitcher become slippery. This gives a greater chance of catching a batch of ants rather than just the original scout ant.
Slippery when wet!
The main component in trapping their prey is the slippery surface of the leaves that slope into the cup of liquid. But scientists have discovered that for periods of time the surface of the leaves are dry and at first this surprised them. Dr. Ulrike Bauer of Bristol’s School of Biological Sciences says, “At first sight, this is puzzling because natural selection should favor traps that catch as many insects as possible.”
The primary food source of this pitcher plant are ants and once this was realised the reason for the temporary switch off became understood. Pitcher plants are known to have the ability to trap quite large groups of ants and scientists experimented by keeping the surface of the trap damp all the time. They found that the traps did not catch as many ants this way. For some reason the plant traps needed a dry period to work the best.
Dr. Bauer says, “Individual scout ants’ search the surroundings of the nest for profitable food sources. When they find a pitcher trap full of sweet nectar, they go back to the colony and recruit many more ant workers. However, a trap that is super-slippery all the time will capture most of these scout ants and cut off its own prey supply.”
By allowing scout ants to escape and bring in reinforcements from the ant nest when the pitcher plant trap is triggered by increased humidity or damp weather the plant captures a greater number of ants gaining more nutrition. When the humidity or weather conditions change the trap is deactivated allowing more scout ants to enter the trap and return to their nests for reinforcements and so the process continues.
Through natural selection the pitcher plant has evolved its own physical form adapting its leaves, nectar and other parts in a way to maximize its catch. It has adapted to exploit local humidity and weather conditions and how ants forage for food to give itself the best chance of continued survival. Quite an impressive a strategy for a brainless plant!
© 20/04/2015 zteve t evans
The main component in trapping their prey is the slippery surface of the leaves that slope into the cup of liquid. But scientists have discovered that for periods of time the surface of the leaves are dry and at first this surprised them. Dr. Ulrike Bauer of Bristol’s School of Biological Sciences says, “At first sight, this is puzzling because natural selection should favor traps that catch as many insects as possible.”
The primary food source of this pitcher plant are ants and once this was realised the reason for the temporary switch off became understood. Pitcher plants are known to have the ability to trap quite large groups of ants and scientists experimented by keeping the surface of the trap damp all the time. They found that the traps did not catch as many ants this way. For some reason the plant traps needed a dry period to work the best.
Dr. Bauer says, “Individual scout ants’ search the surroundings of the nest for profitable food sources. When they find a pitcher trap full of sweet nectar, they go back to the colony and recruit many more ant workers. However, a trap that is super-slippery all the time will capture most of these scout ants and cut off its own prey supply.”
By allowing scout ants to escape and bring in reinforcements from the ant nest when the pitcher plant trap is triggered by increased humidity or damp weather the plant captures a greater number of ants gaining more nutrition. When the humidity or weather conditions change the trap is deactivated allowing more scout ants to enter the trap and return to their nests for reinforcements and so the process continues.
Through natural selection the pitcher plant has evolved its own physical form adapting its leaves, nectar and other parts in a way to maximize its catch. It has adapted to exploit local humidity and weather conditions and how ants forage for food to give itself the best chance of continued survival. Quite an impressive a strategy for a brainless plant!
© 20/04/2015 zteve t evans
References and attributions
Copyright April 20th, 2015 zteve t evans
Copyright April 20th, 2015 zteve t evans
- How to catch more prey with less effective traps:
- Carnivorous Pitcher Plant Outsmarts Insects
- Pitcher plant - Wikipedia, the free encyclopedia