Functional organization of two tympanic neurons in noctuid moths

Abstract

Since Schaller and Timm (1950) suggested ultrasonic reception in the tympanic organ of noctuid moths, it has been conceived by behavioral studies that ultrasonic reception may be convenient for the insects to escape from approach of their predators, bats (Webb, 1953; Treat, 1955). Roeder and Treat (1957) further confirmed the ultrasonic reception in this organ by recording impulses in responses to ultrasonic waves from the tympanic nerve. The tympanic nerve of a moth consists of only two tympanic neurons and one more neuron named B by Treat … Roeder (1959). The cell bodies of the former are found immediately inside the tympanic membrane and the latter in the exoskeleton called Biigel (Eggers, 1919) close to the tympanic membrane. When the tympanic nerve is hung up in the air by a fine silver wire electrode, impulse discharges of those three fibres can be observed simultaneously. Both the tympanic neurons respond to sound, while B neuron does not, with regular discharges. The properties of the tympanic neurons have been explored pretty well by Roeder and Treat (1957), but still some problem remains there to be studied more. The present paper will further clarify the difference in the response pattern between two tympanic neurons. © 1961, PHYSIOLOGICAL SOCIETY OF JAPAN. All rights reserved.