Adult sugar beet root maggot. Photo courtesy
Prasad Burange, North Dakota State University. |
|
Extreme SurvivalInsect Style!
By Jan Suszkiw
January 31, 2007
The sugar beet root maggot, Tetanops myopaeformis, is the
"alpha" pest of insects that attack sugar beets. This is especially true in the
Red River Valley regions of North Dakota and Minnesota, where about 51 percent
of the total U.S. sugar beet crop is grown.
So why are Agricultural Research Service (ARS) scientists and collaborators in Fargo,
N.D., excited about discovering that Tetanops can survive five years of
refrigerated storageand even months in water?
The answer has to do with the saying, "Know thine enemy." In order to
develop novel ways of fighting Tetanops or other insect pests,
scientists must rear large colonies of them in the lab for detailed study. This
can cost thousands, if not millions, of dollars annually. Being able to keep
the insects in cold storage until needed could help cut the cost and save time,
notes George
Yocum, a physiologist in the
ARS
Insect Genetics and Biochemistry Research Unit at Fargo.
Yocum and North Dakota State
University colleagues Mark Boetel and Anitha Chirumamilla are studying cold
storage of Tetanops for another reason: to avoid inbreeding that can
make lab-reared colonies genetically different from targeted populations in
beet fields.
In studies, the researchers compared the respiration, lipid use and
gene activity of dormant Tetanops larvae collected in the field to those
stored in the lab at 41 to 45 degrees Fahrenheit for up to five years. Of
those, 54 percent developed into adult flies when warmed up. The larvae also
survived submersion in tap water at room temperature for three months. Yocum
suspects Tetanops' capacity for survival is an evolutionary adaptation
to flooding and freezing in the Red River Valley region.
Yocum's team is focusing attention on hibernation-like mechanisms that
the insect may use, including metabolism regulation and cell-protecting
antifreeze that's not been observed in other insects.
Potentially, Tetanops could serve as a model organism for
cold-storage applications in other fields, such as improved quarantine
techniques and biomedical efforts to extend the storage and transport of human
organs for transplant.
ARS is the U.S. Department of
Agriculture's chief scientific research agency.