ARS News Service
Agricultural Research Service, USDA
Erin Kendrick-Peabody, (301) 504-1624, ekpeabody[at]ars.usda.gov
September 26, 2003
Mormon
crickets were on the move again this summer. In bands up to three miles deep and
one mile across, they marched across several western states, devastating
croplands and bewildering residents as they blanketed roadways and the sides of
buildings.
But
this time something else was moving with them. A team of researchers, led by
Agricultural Research Service scientist Gregory Sword, was tracking the insects.
For the first time, researchers aimed to find out how far the flightless Mormon
cricket--that looks more like a grasshopper--could move in a day. Their
surprising discovery? One cricket walked more than one-and-a-quarter miles
across steep hills and valleys.
Researchers are investigating Mormon crickets' travels in hopes of one day
predicting their movements. At outbreak levels, the two-inch-long insects walk
in bands of millions of individuals, consuming most plants in
their path, including crops, grasses and ornamentals.
Up
to now, researchers estimated the insect could move about a mile a day. In July,
to determine the pest's true mobility, Sword, Pat Lorch from the University of
North Carolina and Darryl Gwynne from the University of Toronto charted the
migration habits of 12 Mormon crickets in northwestern Colorado. Sword is an
ecologist at the ARS Northern Plains Agricultural Research Laboratory in Sidney,
Mont.
Micro-radio transmitters, about one-quarter of the insect's weight, were glued
to individual crickets. These transmitters provided signals so that the team
could find the same insects 24 hours later.
The
ultimate goal, says Sword, is to develop a model that predicts where migrating
cricket bands will move next. Knowledge of a band's future change in direction,
for instance, would allow land managers to pinpoint pesticide applications,
reducing exposure of non-target species.
Generally, Mormon crickets play an important role in western environments by
providing food for wildlife and contributing to nutrient cycling on rangelands.
ARS
is the U.S. Department of Agriculture's chief scientific research agency.
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