Byers, J.A. 2013. Modeling and regression analysis of semiochemical dose-response curves of insect antennal reception and behavior
Journal of Chemical Ecology 39:1081-1089.
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Abstract--
Dose-response curves of the effects of semiochemicals
on neurophysiology and behavior are reported in many
articles in insect chemical ecology. Most curves are shown in
figures representing points connected by straight lines, in
which the x-axis has order of magnitude increases in dosage
vs. responses on the y-axis. The lack of regression curves
indicates that the nature of the dose-response relationship is
not well understood.
Thus, a computer model was developed
to simulate a flux of various numbers of pheromone molecules
(103 to 5 × 106) passing by 104 receptors distributed among
106 positions along an insect antenna. Each receptor was
depolarized by at least one strike by a molecule, and subsequent
strikes had no additional effect. The simulations showed
that with an increase in pheromone release rate, the antennal
response would increase in a convex fashion and not in a
logarithmic relation as suggested previously. Non-linear regression
showed that a family of kinetic formation functions
fit the simulated data nearly perfectly (R2 > 0.999). This is
reasonable because olfactory receptors have proteins that bind
to the pheromone molecule and are expected to exhibit enzyme
kinetics. Over 90 dose-response relationships reported
in the literature of electroantennographic and behavioral bioassays
in the laboratory and field were analyzed by the logarithmic
and kinetic formation functions. This analysis showed
that in 95 % of the cases, the kinetic functions explained the
relationships better than the logarithmic (mean of about 20 %
better). The kinetic curves become sigmoid when graphed on
a log scale on the x-axis. Dose-catch relationships in the field
are similar to dose-EAR (effective attraction radius, in which a
spherical radius indicates the trapping effect of a lure) and the
circular EARc in two dimensions used in mass trapping
models. The use of kinetic formation functions for dose-response curves of attractants, and kinetic decay curves for
inhibitors, will allow more accurate predictions of insect catch
in monitoring and control programs.
Chemical Ecology