April 12, 2008 | David F. Coppedge

Moths Navigate in the Dark Against the Wind

A moth weighs little more than a piece of paper, but it does things no paper blowing in the wind can do: it can navigate with and against the wind to get where it needs to go.
    Science Daily reported on work by UK scientists who used “entomological radar” to monitor where the little insects go in the dark of night.  Their subjects were silver moths that migrate high in the air for hundreds of kilometers to their breeding grounds.  These moths, they found, “rely on sophisticated behaviors to control their flight direction, and to speed their long-distance journeys into areas suitable for the next generation of moths.”  The work was published in Current Biology.1
    The scientists were not overly surprised that the moths take off on the most favorable days, and use the wind to their advantage.  What was most unexpected was that the moths are not at the mercy of the winds.  The article states, “the moths compensate when the wind direction is substantially off target.
    This ability, called compensation for wind drift, had been seen in low-flying insects like butterflies.  For moths to do this high in the air in the darkness of night means “the moths must have a compass mechanism,” similar to that found in migrating birds.  Though the research was limited to this one species, they suggested “that these mechanisms might prove to be widespread among large windborne insect migrants.”
    The scientists calculated that the silver moths they studied were able to travel 300 km per night – achieving speeds of 30 km per hour.  How they achieve this feat is not clear.  Did they explain how evolution produced flight navigation in insects independently of birds?  No; they just assumed it: “Taken together, our results show that nocturnal migratory moths have evolved a suite of behaviors to facilitate successful migrations to temporary breeding and overwintering areas.”


1.  Chapman, Reynolds, ouritsen, Hill, Riley, Sivell, Smith and Woiwod, “Wind Selection and Drift Compensation Optimize Migratory Pathways in a High-Flying Moth,” Current Biology, Volume 18, Issue 7, 8 April 2008, Pages 514-518.

At the end of the press release, they tagged on a line about global warming.  The scientists should have focused, instead, on the remarkable evidence for design.  Can you imagine a featherweight machine that knows how to sail in the air?  We won’t even bother thinking about how similar wonders could have evolved separately in birds and insects, which are nowhere near each other on Darwin’s tree of lie (04/11/2008).
Exercise:  Make a list of the items of hardware and software you would have to add to a 2-inch scrap of paper blowing in the wind to make it be able to arrive at a precise point 300 km away.  Extra credit: Add to your list how many more items of hardware and software you would have to build onto the paper for it to reproduce itself with copies that could fly back home, having never been there before.  Notice that this implies a requirement: the hardware needs to be lightweight enough to make your scrap of paper not plummet to the ground.

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