Biocurious is a weblog about biology, quantified.

Hot off the Press: The Birds and the Bees [updated]

by PhilipJ on 23 June 2005

Well, not specifically bees, but flying insects in general. As reported in this week’s Nature, some birds, despite being extremely different in a physiological sense, fly like insects!

Hummingbirds and many flying insects locomote through a fluid medium at similar Reynolds number, and as such, their flying mechanisms are thought to be very similar. Like insects of comparable size, the hummingbird’s up and downstrokes are assumed to contribute equally to weight support during hovering. To test this hypothesis, scientists used particle image velocimetry to observe the wakes produced by hovering Selasphorus rufus, or rufous hummingbirds.

What they found, however, was an asymmetry in force generation. Approximately 75% of their weight is supported during the downstroke, while only 25% is supported in the upstroke. However, there was also evidence of leading-edge vortices created by the downstroke, which is a known component of the insect hovering mechanism.

To read the abstract, click here (subscription required for full article) UPDATED or click here to read Nature’s own news piece.

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