Electrophysiological and behavioural responses to lactic acid stimuli in larvae of Tenebrio molitor L. (Coleoptera: Tenebrionidae) and permeability of antennal sensilla

Abstract. Of the five types of antennal sensilla in larvae of Tenebrio molitor L., only the uniporous long pointed pegs and papillate plates are readily permeable to an aqueous solution of CoCl₂, which is generally indicative of a gustatory function. An electrophysiological investigation confirms the gustatory role of the papillate sensilla on the antenna, and it suggests that they are responsible for mediating the behaviour of larvae toward lactic acid stimuli. Larvae with ablated antennae do not aggregate as would normal animals in the presence of lactic acid stimuli. The uniporous long pointed pegs show no response to lactic acid or other aqueous stimuli.