Air Date: Week of June 22, 2001

Living on Earth’s Maggie Villiger reports on a mysterious technique hornets use to build a level nest.

Transcript

CURWOOD: Just ahead, a corporate spy campaign against Greenpeace. First, this animal note from Maggie Villiger.

[Music up and under[: "Update Theme and Stings" composed by Allison Dean]]

VILLIGER: Oriental hornets are meticulous architects. Found throughout the Middle East, these insects carefully orient their nests with respect to gravity. Each cell in their comb points along the exact same axis, away from the Earth. Scientists have long wondered how hornets can precisely detect the direction of gravity's pull. Now, researchers have discovered what they think in a kind of "gravity detection system," that hornets actually install in their homes. Every cell in the nest comb has its own domed roof. And right in the center of that roof, the hornets use saliva to glue a tiny crystal into place. These stones are made up of mostly titanium and iron. It's unclear whether the hornets collect them from somewhere, or secrete them in some way. Researchers think the hornets may use these crystals in combination with a mysterious organ in their heads, that also contains several metals. Perhaps, scientists say, the crystals form a kind of invisible net, that acts like a surveyor's level, helping the hornets build symmetrical, balanced cells. Scientists are now investigating whether these crystals influence the way larvae develop in the cells. That's this week's animal note; I'm Maggie Villiger.

[Music up and over: "Update Theme and Stings" composed by Allison Dean]

CURWOOD: And you're listening to Living On Earth.

[Cutaway 2 Music: John Fiuczysnki & John Medeski: "Vog" ]