ELECTROPHYSIOLOGICAL STUDIES OF ARTHROPOD CHEMORECEPTION. III. CHEMORECEPTORS OF TERRESTRIAL AND FRESH-WATER ARTHROPODS

Abstract

1. Electrophysiological tests with externally applied, fluid-filled electrodes were performed upon thirty-seven species representing four classes of arthropods. Afferent chemoreceptor impulses were recorded in animals of five types: a crayfish (Cambarus), a millipede (Pseudopolydesmus), two orthopterans (Ceuthophilus and Hadenoecus), a helomyzid fly (Amoebaleria), and six species of butterflies. 2. Receptors sensitive to chemical, tactile, and temperature stimuli within normal physiological ranges are found in certain Lepidoptera (Epargyreus and Limenitis) and Diptera (Amoebaleria). Receptors with a dual sensitivity to at least two of the above types of stimulation are found in Pseudopolydesmus, Ceuthophilus, and Hadenoecus. It is concluded that multiple sensitivities of receptors are not exceptional in arthropods. 3. Chemoreceptors sensitive to amino acids, but insensitive to tactile and temperature stimuli, are found on the chelae and protopodites of the first two walking legs of Cambarus bartonii sciotensis. 4. With the present recording method, spike potentials from chemoreceptors represent increases in positivity at the distal tip of the receptor cell, relative to the cell body. 5. Relationships between functional characteristics of chemoreceptors and the natural history of the animals are discussed.