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Listening to Larvae
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Entomologist Richard W. Mankin has
eavesdropping down to an art. Using a self-developed computer program that can
tell the difference between the sounds made by termites, root weevils, and many
other insects, he's found a way to expose hidden insects that infest and damage
packaged goods, ornamentals, and other valuable agricultural commodities, even
golf courses.
"Typically," says Mankin, "the only way to determine whether
there is an infestation of insect larvae is to wait for adults to emerge or to
dig or cut out a sample. By that time, it can be too late. It's also not
economical to dig up large parts of a field or crop to check for
infestations."
Mankin, who is with the ARS Center for
Medical, Agricultural, and Veterinary Entomology's Post-Harvest and
Bioregulation Research Unit in Gainesville, Florida, has developed a
nonintrusive eavesdropping tool using a sensor that measures vibrations given
off by insects as they move and feed.
The sensor can be attached to a spike that is pushed into soil or poked into a
tree trunk, or it can be clamped to a plant stem. By poking the specially
rigged nail into a tree or a plank, Mankin can tell whether it's infested with
termites just from the sounds he hears. A series of scrapes and clicks in
particular rhythms at particular frequencies reveal insects "on the
take." Mankin can also use the specially designed clamps to eavesdrop on
larvae in stored products or sawflies inside wheat stems.
Different insects give off different sounds, depending on their feeding and
movement patterns, their sizes, and what they are eating. Mankin has developed
a computer program to distinguish larval movement and feeding activity from
background noises, like wind or blowing leaves, and in many cases, the program
can distinguish different insects from each other. This is done partly by
matching new sounds with previously recorded sounds.
"Our long-term goal is to develop rapid, nondestructive techniques for
pinpointing hidden infestations, which should reduce pesticide use and decrease
treatment costs," Mankin says. —By
Tara
Weaver-Missick, Agricultural Research Service Information Staff.
Richard W. Mankin is
at the USDA-ARS Center for Medical,
Agricultural, and Veterinary Entomology, Postharvest and Bioregulation
Research Unit, 1700 S.W. 23rd Dr., Gainesville, FL 32608; phone (352)
374-5774, fax (352) 374-5781. |
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"Listening to Larvae" was published in the
March 2001
issue of Agricultural Research magazine.
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Last Modified: 06/21/2002
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