title: Sexual differentiation and developmental stage identification of the Indian cockroach, Pycnoscelus indicus (Blattodea: Blaberidae).
abstract: We found that sexual differentiation of all the nymphal stages of Pycnoscelus indicus (Fabricius) was possible by observing the developmental features of their posterior abdominal segments. Using this observation, the sex of even the 1(st) stage instar nymph could be determined. The female of the 1(st) to 6(th) stage instar nymph possess a V-shaped notch at the middle of the posterior edge of the 9(th) sternite. This notch is not seen in the male nymph. In the female 7(th) stage (final stage) instar nymph, the styli were not apparent and, the 8(th) and 9(th) sternites became degenerated and were covered over by the profoundly developed 7(th) sternite. In contrast, all stages of the male nymph showed the presence of styli. Thus, it is possible to differentiate the sex of all the stages, from 1(st) to 7(th), of the nymph of P. indicus taxonomically. Moreover, it is also possible to identify the various specimens as to which stage the nymphal instar belong to, by counting the number of cercal segments from the ventral view.
authors.affiliation: Civil International Corporation, 1-10-14 Kitaueno, Taito, Tokyo 110-0014 Japan.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Komatsu
authors.affiliation: Laboratory of Parasitology, School of Veterinary Medicine, Azabu University, 1-17-71 Fuchinobe, Sagamihara, Kanagawa 252-5201 Japan.
authors.forename: Hong-Kean
authors.initials: HK
authors.lastname: Ooi
authors.affiliation: Yamazaki Gakuen University, 4-7-2 Minami-osawa, Hachioji, Tokyo 192-0364 Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Uchida
mesh_terms: D000818:Animals; D001699:Biometry; D003058:Cockroaches / Q000033:anatomy & histology* / Q000254:growth & development*; D005260:Female; D007194:India; D008018:Life Cycle Stages; D008297:Male; D012733:Sex Differentiation