Chemoreception in larvae of the moth Lymantria dispar

Taste sensitivity in response to diet components was studied in larvae of the gypsy moth, Lymantria dispar, by means of electro-physiological and behavioural approaches. Dose-response relationships were studied for NaCl, sucrose, and nicotine solutions with the aim of better characterizing chemoreceptor cells involved in gustation. Results showed that medial sensilla styloconica in the galea are specifically sensible to deterrent substances like salt and nicotine; instead, lateral sensilla showed a marked sensitivity to sugars. Morphological and electrophysiological data on the possible role of the sensilla basiconica of the maxillary palps are also reported. On the basis of the results obtained, it is proposed that taste chemoreceptor cells in the gypsy moth should be categorized as phagostimulatory or deterrent on the basis of their behavioural effects, rather than of their responding to specific stimuli.