Sensory structures on the larval antennae and mouthparts of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae)

Abstract

The present study is, to the best of our knowledge, the first descriptive research focusing on the structure of the larval gustatory and olfactory sense organs of the tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), using scanning electron microscopy. Various sensilla types were identified and their mean lengths were determined. Three types of sensilla were observed on the pedicel of the antenna: sensillum trichodeum, sensillum chaeticum, and sensillum basiconicum. Subsequently, three sensilla basiconica and one sensillum styloconicum were reported on the flagellum. Mouthparts carried six types of sensilla at various sites. Six pairs of sensilla chaetica and a pair of epipharyngeal setae were located on the labrum. On the maxillae, the cardo bore one sensillum chaeticum while the galea carried two pairs of sensilla basiconica and one pair of sensilla styloconica. The maxillary palp carried eight short sensilla basiconica, sensillum digitiformium, and sensillum placodeum. The labial palp bore long sensillum styloconicum and short chaeticum. The findings provide useful information that may help to understand the olfactory and gustatory perceptions that influence larval preferences for plants as a source of food.