PERCEPTION OF CARBON DIOXIDE BY LARVAE OFORTHOSOMA BRUNNEUM(COLEOPTERA: CERAMBYCIDAE) AS INDICATED BY RECORDINGS FROM THE VENTRAL NERVE CORD

Abstract

Extracellular hook electrode recordings were made of activity in the ventral nerve cord of the larvae ofOrthosoma brunneum(Forster) during application of 30% CO₂to the head region. The work involved bilateral amputation of the tip segments of antennae, maxillary palps, and labial palps so that each specimen bore only one intact pair of the three sensory organs. Larvae with only intact antennae exhibited no response to CO₂in the ventral nerve cord; larvae with only maxillary palps did respond; larvae with only labial palps did respond, but less noticeably. Maxillary and labial palps are sites of CO₂reception inO.brunneum.