ABSTRACT
Pheromones, chemical signals for intraspecific communication (Karlson and Luescher 1959), are usually blends of chemical compounds in species-specific mixtures. Airborne pheromones of moths often consist of only two or three chemical components, each of which is perceived by a separate type of receptor neurons. Each of these neurons, called olfactory specialists (Boeckh et al. 1965) is tuned to one biologically significant compound; it responds to compounds other than the key compound only if presented at 10-to 10,000-fold higher stimulus concentrations. The composition of a pheromone blend is represented by the pattern of excitations across the types of specialists (Baker et al. 2004). Odor specialists are known also for compounds other than pheromones,
4.1 Introduction ....................................................................................................99 4.2 Aspects of Pheromone Communication ....................................................... 100 4.3 Insect Antennae and Olfactory Sensilla ....................................................... 104 4.4 Electrophysiology ......................................................................................... 107 4.5 Sensitivity of Pheromone Receptor Neurons and Behavioral Responses ..... 110 4.6 Elementary Receptor Potentials ................................................................... 114 4.7 Inhibition of Pheromone Receptor Neurons ................................................. 117 4.8 Concentration Detectors and Flux Detectors ............................................... 120 4.9 Olfactory Transduction, Extracellular .......................................................... 121 4.10 Diffusion on the Hairs ..................................................................................124 4.11 Kinetic Model ...............................................................................................124 4.12 Five Functions of the Pheromone Binding Protein ....................................... 126 4.13 Pheromone Degradation and Deactivation ................................................... 128 4.14 Receptor Molecules, Ion Channels, and Sensory Neuron Membrane
Protein ........................................................................................................... 130 4.15 Olfactory Transduction, Intracellular ........................................................... 132 4.16 Temporal Coding .......................................................................................... 134 Acknowledgments .................................................................................................. 134 References .............................................................................................................. 134
such as plant volatiles or carbon dioxide. Less sharply tuned olfactory neurons have been called generalists. They may show varying and overlapping response spectra such as found in moths (Schneider et al. 1964) or in pine weevils (Mustaparta 1975).
