Until now, it was thought that the directions of these swarms were predominantly directed by prevailing winds. Now, Hebrew University of Jerusalem scientists have shown that a physiological trait of these grasshoppers namely their polarization vision -- provides them with a built-in source of "surface analysis" a discovery that could pave the way for efforts to effectively combat this periodic scourge by controlling their natural inclination to fly over land rather than water.

The desert locusts, known scientifically as Schistocerca gregaria, are able to swarm for great distances and in numbers measuring in the millions. During the locust invasion of November 2004 in Israel, it appeared that a swarm came in an easterly direction over Sinai up to the Gulf of Eilat, then turned northward without crossing the water. Only when the swarm reached the northern tip of the gulf did some of them turn again east in the direction of Aqaba and other areas of Jordan, as well as straight north over southern Israel.

This observation led to examination by scientists of the Hebrew University of Jerusalem Department of Evolution, Systematics and Ecology and the Interuniversity Institute for Marine Sciences in Eilat to examine how the locusts were able to identify the gulf water and knew not to fly over it. The research focused on the ability of the locusts to identify polarized light. This is a trait which is lacking in humans but exists among other species, such as fish and insects.

The research was conducted by Dr. Nadav Shashar, who is considered a leading world expert on polarized sight, working with two students, Shai Sabah and Noa Aharoni. The research was published in a recent issue of the journal of the British Royal Society, Biolog
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Contact: Jerry Barach
jerryb@savion.huji.ac.il
972-2-5864772
The Hebrew University of Jerusalem
11-Aug-2005