Chili pestiferous thrips Thrips parvispinus (Karny, 1922) and Thrips tabaci (Lindman, 1889) (Thripidae: Thysanoptera) antennal structural characterisation

Thrips are among the most serious pests attacking many economically important crops. They causes significant damage to plants by lacerating and sucking sap from the leaves, growing tips, flowers, and fruits leading to silvery spots, stunted growth, flower drop, and fruits deformation, ultimately resulting in severe economic yield losses in many crops. In addition to the damage caused, they act as vectors for various viral plant diseases. Antennal sensilla plays a crucial role in the chemical communication of thrips. However, studies on the types of sensilla in thrips are limited to a few species. Therefore, using scanning electron microscopy (SEM), this study examined the different types of sensilla in two pestiferous thrips species, Thrips parvispinus Karny and T. tabaci Lindman. The antenna of the thrips were found to consist of nine types of sensilla viz., Bohm bristles (BB), microtrichia (MT), sensilla basiconica(SB), sensilla campaniformia(SCa), sensilla cavity(SCav), sensilla chaetica(SCh), sensilla coeloconica(SCo), sensilla styloconica(SSt), and sensilla trichoidea(ST). The microscopy observations revealed that all these sensilla were present in T. parvispinus while SSt was absent in T. tabaci. Sensilla chaetica were more abundant in Thrips tabaci than in Thrips parvispinus. Based on the results, the types of antennal sensilla and their functions in thrips are also discussed.