Ecological Adaptation and Speciation: The Evolutionary Significance of Habitat Avoidance as a Postzygotic Reproductive Barrier to Gene Flow

Table 2

Changes to olfactory system that can potentially affect the behavioral orientation of insects to plants.

Genetic change	Effect
Odorant binding-protein conformation	Determines nonpolar compounds carried to dendrite of chemoreceptor
Change in conformation of protein at receptor site on chemoreceptor	Influences sensitivity of cell to particular compound
Alter numbers of receptor sites for particular chemical on chemoreceptor	Alter sensitivity of cell to particular compound
Alter second messenger or membrane properties of + or − chemoreceptor	Alter sensitivity of + or − cell overall
Alter gene expression pattern of receptor proteins on + and − cells	Switch effect of stimulation from + to − or vice versa
Alter wiring of sense cells or interneurons	Switch effect of stimulation from + to − or vice versa
Alter levels of one or more neuromodulators at synapses	Alter weighting of different + and − inputs
Alter sign of synaptic inputs in path to controlling center	Alter weighting of different + and − inputs