The mouthparts and sensilla of the adult tomato leafminer moth, Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae)

Abstract

In this study, investigation of the morphology and distribution of mouthpart sensilla in the adult tomato leafminer moth, Tuta absoluta Meyrick (Lepidoptera: Gelechiidae), using a scanning electron microscope (SEM) is performed. SEM studies examining the mouthparts of Gelechiidae have been noted to be rare; moreover, there have been few investigations on the sensory structures of adult T. absoluta, despite the fact that it is an important pest. In adult T. absoluta, mouthpart structures include the labrum, maxillae comprising two maxillary galeae that form a proboscis, two maxillary palps, and two labial palps. Mandibles were not observed in all studied specimens (30 adults). The proboscis resembles that in other lepidopterous insects and is 1.48 ± 0.08 mm long. Its outer surface is covered with lamellar scales, dense microtrichia, and four sensillum types, that are, aporous sensilla chaetica, uniporous sensilla chaetica, uniporous sensilla styloconica, and aporous sensilla squamiformia. Uniporous sensilla basiconica were also found on the internal face of the proboscis. The labial palps are three-segmented and are known to bear three types of sensilla: squamiformia (present on all three segments), campaniformia, and coeloconica. In this study, we focus on the functional importance of the morphology and distribution of sensilla campaniformia on these labial palps.

Keywords: Adult moths; Labial palp; Proboscis; Sensilla; Tuta absoluta; Ultrastructure.