Sensillum types on the proboscis of the Lepidoptera: a review

Abstract

Summary The external surface of lepidopteran proboscides may bear six morphological types of sensilla: chaeticum, basiconicum, styloconicum, coeloconicum, filiformium, and campaniformium, with the first three types being the most common. There are four types of pore-system: aporous, uniporous, multiporous, and uniporous-multiporous. Sensilla chaetica and campaniformia are aporous sensilla with a tactile or a proprioceptive function, respectively. Aporous sensilla filiformia are probably vibroreceptors. Uniporous sensilla with a gustative function exist in sensilla basiconica, styloconica and coeloconica. Multiporous sensilla were found in long sensilla basiconica and seem rare. Uniporous-multiporous sensilla are relatively common and are to be found both in sensilla styloconica (Arctiidae, Noctuidae) and in sensilla basiconica (Adelidae, Pyralidae, Arctiidae, Noctuidae). It is difficult to establish their function (gustative or olfactive). More extensive research would make it possible to discover them in other families. Only gustative uniporous sensilla basiconica exist in the food canal. The morphology of the proboscis and the distribution of sensilla are adapted to food habits.