A STUDY OF CHEMORECEPTION IN AQUEOUS AND GAS PHASES

Open Access
Publisher Website
Google Scholar
Abstract
1. Quantitatively controlled stimuli were administered to populations of an amphibious beetle, Laccophilus maculosus Germar, to determine whether the same chemoreceptors are sensitive to gaseous and liquid stimuli, and to discover qualitative or quantitative specializations in the function of different receptor groups. 2. Sensilla basiconica on the tips of the antennae are the principal chemoreceptors for both gaseous and liquid stimuli. The lower threshold of antennal receptors, relative to receptors elsewhere on the animals, is not due to a larger number of sensilla on the antennae and indicates an inherent specialization of the receptors themselves. 3. Morphological and experimental evidence strongly indicates that the sensilla basiconica on the tips of the maxillary and labial palpi also function as chemoreceptors for stimuli in solution, although their thresholds are higher than those of antennal receptors. The concentration of gases could not be raised to a level adequate for stimulation of receptors on the palpi and they must play little or no part in mediating reactions of the animals in air. 4. HCl, 1-pentanol, and NaCl all stimulated receptor areas on the tips of the antennae and palpi, and no evidence was found for specialization of any morphologically or topographically distinguishable receptor groups sensitive to only a particular modality of stimulus. Chemoreceptors were not found on parts of the body other than the antennae and palpi. 5. The findings are discussed with reference to possible identity of fundamental mechanisms limiting the effectiveness of chemical stimuli in the two physical states, and general concepts of olfaction and gustation.