Morphology and distribution of antennal sensilla in the postembryonic developmental stages of Cimex hemipterus Fabricius

Morphology and distribution of various types of sensilla in the postembryonic developmental stages on antennae of Cimex hemipterus were studied using scanning electron microscopy. Four major types of mechanosensilla and chemosensilla, i.e., serrated grooved bristles, unserrated grooved bristles, smooth walled sensilla with pointed tip, and sensilla basiconica were identified. No sexual dimorphism was observed. The sensillar population of serrated grooved bristles and unserrated grooved bristles increased two and six folds, respectively, while smooth walled sensilla with pointed tip and sensilla basiconica increased 3.5 folds from the first nymphal instar to males and females. A high degree of correlation between number of various types of sensilla and different nymphal instars, males and females were observed. Mechanosensilla were found distributed in all the four segments (scape, pedicel, flagellum 1, and flagellum 2) while smooth walled sensilla with pointed tip and sensilla basiconica were mainly confined to the two flagellar segments.