Figure 14. Summary of the electrophysiological analysis of the adequacy of the three humidity transduction models.

Analysis is based on the specific predictions drawn from each of the models by determining the effect of three temperature levels on the responses of the moist and dry cells to oscillating changes in vapor pressure expressed as oscillation in relative humidity, saturation deficit or wet-bulb temperature. +,++and+++stand for categories of increasing response magnitude predicted by the models. Obtained response ranges of each cell are normalized to its response calculated for 30°C. A. Humidity stimulation. B. In the mechanical hygrometer swelling and shrinking of a hygroscopic sensillum wall due to changes in the relative humidity governs the response of the moist and dry cells. C. In the evaporation detector, humidity affects the lymph concentration outside the dendrites of the moist and dry cells, involving the saturation deficit. D. In the psychrometer, activity of the moist cell is initiated by evaporative cooling and actiovity of the dry cell by the temperature. Asterisks indicate correspondence between predicted and obtained responses. Pw water vapor pressure, Ps saturation water vapor pressure, Pw/Ps relative humidity, Ps-Pw saturation deficit, T temperature, dry T dry-bulb temperature, wet T wet-bulb temperature.