Tentacles Catapult Insects

small red tentacles on the yellow leaf of a drosera flower

Biological Strategy

Round-leaved sundew

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Capture, Absorb, or Filter Organisms

Many living systems must secure organisms for food. But just as one living system must capture its prey to survive, its prey must escape to survive. This results in capture and avoidance strategies that include trickery, speed, poisons, constructed traps, and more. For example, a carnivorous plant called the pitcher plant has leaves formed into a tube that collect water. Long, slippery hairs within the tube face downward. When insects enter the tube seeking nectar, they lose their footing and slide inside, unable to climb out and escape being eaten and digested by the plant.

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Flowering Plants

Clade Angiosperms (“receptacle seed”): Dandelions, oaks, grasses, cacti, apples

With 416 families containing some 300,000 known species, angiosperms are the most diverse group of plants, and they can be found around the globe in a wide variety of habitats. They are characterized by seeds that grow enclosed in ovaries, which are enclosed in flowers. The floral organs then develop into fruits of myriad kinds and dimensions, from simple seed casings on maples to elaborate fleshy growths like papayas. The oldest flower known from fossils, Montsechia vidalii, appeared during the Jurassic Period 130 million years ago. They are the primary food source for herbivorous animals, which in turn makes them the indirect food source for carnivores as well.

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Snap-tentacles on leaf of southern Australian sundew capture ground prey by catapulting them to their center via a touch-sensitive head.

The South Australian sundew is a carnivorous plant that utilizes a capturing mechanism to provide itself with sustenance and nourishment. It captures its prey using tentacles that have a touch-sensitive head. When the head encounters movement, it activates a contracting mechanism (which is not yet fully understood but has two hypothesized mechanisms of its own) in the cells of the tentacle. The catapult mechanism is unique to this carnivorous plant; many other plants rely solely on the stickiness of their centers to trap prey. When the head becomes activated certain cells on the end closest to the plant body extend while cells farther out on the tentacle contract, causing the tentacle to bend upwards. In a 360-degree motion, the tentacle launches the prey to the center of the leaf. The movement of these snap-tentacles is a one-time motion. The tentacles cannot be utilized more than once due to hypothesized snapping of cells during the elongation/contraction process. The triggering of the head on the tip of the snap-tentacle is also highly precise; the head will not be triggered by vibrations from prey already trapped and must be activated via a ground-to-tentacle interaction.

The usefulness of these snap-tentacles is that they position the prey in a more vulnerable position in the center of the glue-tentacles, which reside in the middle of the trap leaf. These glue-tentacles then take two minutes to pull the prey in deeper and its active enzyme enables the plant to decompose the insect and utilize its nutrients to the fullest.

For detailed videos of the process, please visit the open-access journal: here.

Last Updated August 23, 2016

References

Journal article

Catapulting Tentacles in a Sticky Carnivorous Plant

PLoS ONE | 27/09/2012 | Simon Poppinga, Siegfried Richard Heinrich Hartmeyer, Robin Seidel, Tom Masselter, Irmgard Hartmeyer, Thomas Speck |

Paul V. A. Fine

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