Ultra structural study on different sensory structure and some associated body parts of mango mealy bug, Drosicha mangiferae (G.) by scanning electron microscopy

Abstract

Licensed under a Creative Commons Attribution 4.0 International License Observation on the ultra-structure of both mouth parts and sensory apparatus of mango mealy bug, Drosicha mangiferae (Stebbing, 1903) (Hemiptera: Coccoidea) was carried out. Seven segments of different size in each antenna have been identified in D. mangiferae in the present observation. Out of the all segments, the terminal segment was the longest trailed by third and second flagellomere in downward order. Sensilla with flexible socket was noted in almost every body parts in the present observation. Abundant wax pores on the dorsal and ventral surface on the body surface of mealy bug secrete spiral wax filaments. Two types of wax pores namely trilocular and quinquelocular were observed. Leg consisted of basal coxa, trochanter, femur, tibia and tarsus which ended with curved claw and two claw digitules.Hair like sensilla trichoidea was mostly abundant in antenna and was of four subtypes. All of these function as mechanoreceptor or gustatory receptor. The labium of second instar nymphs of D. mangiferae had three segments with a median labial groove for housing stylet fascicle. Ten pairs of trichoid sensilla were found in the labium that also function as mechanoreceptors. Long hair like sensilla chaetica with pointed tip (SCh) in five pairs was also observed. Apart from that different kind of mechanoreceptor sensilla with flexible sockets, sensilla were found having inflexible sockets and pores with probable olfactory function.