Above- and belowground olfactometers for high throughput bioassays
T. Turlings1, A. Davison2, I. Ricard2, C. Tamo1, S. Rasmann1 and M.
Held1
1Institute of Zoology, University of Neuchâtel, Neuchâtel,
Switzerland
2EPF-Lausanne, Mathematics/Statistics, Lausanne, Switzerland
Customary procedures to determine attraction to odor sources and to identify
the substances that are responsible for the attraction require tedious
and time-consuming bioassays, as well as separate experiments using specialized
methods for the collection, analyses, and identification of the chemicals.
The inclusion of several different odor sources and treatments in such
studies can make them exceedingly lengthy and impossible to accomplish
within a reasonable time period. We have developed two types of six-arm
olfactometers to facilitate our research on the chemical signals emitted
by insect-damaged plants that serve to attract parasitic wasps and entomopathogenic
nematodes, which are natural enemies of the damaging insects. One olfactometer
is used to study aboveground and another to study belowground attraction.
Using log-linear models for the statistical treatment of the data allows
for the testing of multiple individuals at the same time and the models
control for overdispersion and positional effects. In addition to allowing
us to test the relative attractiveness of up to six odor sources at the
same time, the equipment is also designed to simultaneously sample part
of the volatiles emitted by the odor sources, which can subsequently be
identified and quantified. The 6-arm olfactometers offer several advantages
over conventional olfactometer designs and have proven to be highly effective
in aiding us to identify key attractants involved in tritrophic interactions.
The above- and belowground olfactometers can be attached to each other
and we currently use this feature to investigate how aboveground herbivory
affects belowground interactions and visa versa.
Paper presented
at Measuring Behavior 2005
, 5th International Conference on Methods and Techniques
in Behavioral Research, 30 August - 2 September 2005, Wageningen, The
Netherlands.
© 2005 Noldus
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