Sticky Hairs Capture Insects

two green plants with small hairs on narrow green leaves are seen against a dark background with plants and greenery

Biological Strategy

Flypaper plant

AskNature Team

Image: C. E. Timothy Paine / Flickr / CC BY - Creative Commons Attribution alone

Attach Permanently

A living system can conserve energy by attaching permanently to a particular site because it can take advantage of resources that come its way, rather than expending energy to move to resources. A permanent attachment, intended to last the lifetime of the living system, creates special challenges. For example, physical mechanisms, such as the anchor that holds a marine algae to the ocean’s bottom, must be able to withstand forces that can pull it off its substrate. Chemical mechanisms, such as a barnacle’s glue, must avoid both physical and chemical breakdown, such as being dissolved by water.

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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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Sticky secretions from leaf hairs of Roridula plants help capture insect prey via a multi-step adhesive capture process.

“Curious to find out exactly how R. gorgonias leaves ensnare their prey, Dagmar Voigt and Elena and Stanislav Gorb from the Max Planck Institute for Metals Research and Kiel University, Germany, decided to take a closer look at the hierarchy of hairs on R. gorgonias leaves…Voigt and her colleagues suspect that hapless insects fall foul of the plant’s sticky leaves in a cascade of events. First, the insect brushes against, and sticks to, a long hair. As it begins to thrash around, it contacts more of the long hairs, becoming entangled in their sticky secretions. Next, it contacts the stiffer medium length hairs with intermediate strength adhesive and is finally trapped by the rigid short hairs with the strongest glue. Eventually the struggling insect runs out of energy and is immobilised.” (Knight 2009:ii)