Wings Allow Movement in Viscous Solutions

photograph of brown insect with iridescent wings against black background

Biological Strategy

Fairy flies

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Image: Harry Taylor / Flickr / Some rights reserved

Move in/on Liquids

Water is not only the most abundant liquid on earth, but it’s vital to life–so it’s no surprise that the majority of life has evolved to thrive on and under its surface. Moving efficiently in and on this dense and dynamic substance presents unique challenges and opportunities for living systems. As a result, they have evolved countless solutions to optimize drag, utilize surface tension, fine tune buoyancy, and take advantage of various types of currents and fluid dynamics. For example, sharks can slide through water by reducing drag due to their streamlined shape and specially shaped features on their skin.

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Move in/Through Gases

Living systems must move through gases (which are less dense than liquids and solids) such as those in the earth’s atmosphere. The greatest challenge of moving in gases is that because the living system is heavier than the gas, it must overcome the force of gravity. Moving efficiently in this light medium presents unique challenges and opportunities for living systems. As a result, they have evolved countless solutions to optimize drag and increase lift so that they can stay aloft and take advantage of variable currents. Additionally, they must overcome gravity when moving from a liquid or solid into the air. The fairyfly, the smallest known insect, is a tiny wasp that must move through the air. To the wasp, air feels like a heavy liquid and to move through it, it uses special feathery oars rather than wings.

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Insects

Class Insecta (“an insect”): Flies, ants, beetles, cockroaches, fleas, dragonflies

Insects are the most abundant arthropods—they make up 90% of the animals in the phylum. They’re found everywhere on earth except the deep ocean, and scientists estimate there are millions of insects not yet described. Most live on land, but many live in freshwater or saltwater marshes for part of their life cycles. Insects have three distinct body sections: a head, which has specialized mouthparts, a thorax, which has jointed legs, and an abdomen. They have well-developed nervous and sensory systems, and are the only invertebrate that can fly, thanks to their lightweight exoskeletons and small size.

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Wings of fairy flies allow them to move in relatively viscous solutions by being feathery rather than solid structures.

“It’s a whole solar-powered flotilla, majestic in the soaring hot air currents…And there are breast-stroke straining fairy flies–creatures so small that ordinary garden air is as thick as water to them, and they maneuver in the up-blast not with wings, but with sticking-out feathery oars.” (Bodanis 1992: 119)

Bodanis, D. 1992. The secret garden. New York (NY): Simon & Schuster. 187 p.

Last Updated August 18, 2016

References

Book

The Secret Garden: Dawn to Dusk in the Astonishing Hidden World of the Garden

Simon & Schuster | 01/11/1992 | David Bodanis

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