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Abstract
Detection of Volatile Chemicals by Monitoring the Behavior of Trained
Insects
Glen
C Rains, Biological and Agricultural Engineering
W. Joe Lewis, USDA-ARS, Adjunct Faculty, Entomology Dept.
Microplitis
croceipes (Cresson) (Hymenoptera: Braconidae) are parasitoid wasps that
can be trained to detect target odors with a wide range of chemcial structure.
Wasps are trained to a target odor through classical associative learning
techniques. Wasps are trained by associating the target odor to food while
feeding on sugar water. When the wasp subsequently detects the target
odor, it responds with a specific behavioral response, area-restricted
searching, that is indicative of food searching. Area-restricted searching
is characterized by specific body and antennae movements, and several
wasps exhibiting area-restricted searching within the same area is known
as crowding. A computer vision system consisting of a laptop, web camera,
and software package (Visual Cortex) was assembled to objectively quantify
the crowding behavior of several insects. The system was able to measure
the crowding behavior of five female M. croceipes hand trained to detect
3-octanone, a common odor from several fungal plant pathogens. Further,
the system was able to distinguish between the crowding response of trained
M. croceipes exposed to 0.5mg and 0.1mg of 3-octanone and a control within
20 seconds. Further testing has shown that another wasp parasitoid (Cardioceles
nigriceps) as well as house flies can be trained through associative learning
and used as detectors for specific chemicals.
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