LOCALIZATION IN THE CENTRAL NERVOUS SYSTEM OF LARVAL MANDUCA SEXTA (LEPIDOPTERA: SPHINGIDAE) OF AREAS RESPONSIBLE FOR ASPECTS OF FEEDING BEHAVIOUR

Abstract-The role of certain parts of the central nervous system in the control of feeding behaviour, and especially of chewing, has been investigated by the use of lesions. Cutting the connectives behind the suboesophageal ganglion disinhibits chewing, so that continuous rhythmic mandibular movements occur even in the absence of mechano- or chemostimulation of the mouthparts. Stimulation of the mouthparts with plant material leads to an increased rate of chewing and to maintained ingestion. Isolating the suboesophageal ganglion from the protocerebrum does not prevent the induction of chewing and maintained ingestion. Severing the frontal connectives (uni- or bilaterally) eliminates maintained ingestion but not the ability to chew. The centrally isolated suboesophageal ganglion is capable of producing a co-ordinated chewing behaviour, but not of ingesting food. Key Word Index: Manduca sexta; feeding behaviour; suboesophageal ganglion INTRODUCI’ION Feeding is a prominent and very important behaviour of insects. The neural substrates of insect feedin