Video: Why Insect Wings Don't Fracture

Credit: Dirks and Taylor, PLoS ONE (2012)

How can an insect's gossamer wings survive the stresses of flexing, twisting, bending, and flapping millions of times? Tests similar to those used to analyze aircraft parts reveal that the secret lies in the wings’ veins. Researchers mounted sections from the rear wings of lab-raised desert locusts—Schistocerca gregaria, an insect pest famed for migrations lasting several days and covering several thousand kilometers—into tiny frames and stretched the wings until they cracked (see video). Unsurprisingly, the membrane between veins, which ranges from a mere 1.7 to 3.7 micrometers thick and is mainly composed of cross-linked proteins, had little resistance to the propagation of cracks. But when cracks reached a wing vein, their growth typically slowed or stopped. Overall, veins boosted a wing’s resistance to crack growth by about 50%, the researchers report online this week in PLoS ONE. Although scientists have previously proposed that the veins might act as barriers to crack growth, the new tests are the first to support the notion. The new findings could help engineers to better design light yet strong and durable wings for small flying vehicles that could be used for reconnaissance, for example, or operated in environments too dangerous for people and inaccessible to ground vehicles.

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