Early Events in the Pupal-Adult Molt of Aedes triseriatus (Diptera: Culicidae): Spatial and Temporal Considerations1

Abstract

Early events in the pupal-adult molt of Aedes triseriatus (Say) were studied in serial paraffin sections. Four widely separated sites were examined in pupae of known hourly age post-larval-pupal ecdysis. Although early increase in epidermal cell volume was evident at two of the four sites, there was no evidence of increase in cell number, i.e., no mitotic figures were seen. In pupae reared at 27°C, molting fluid (taken as an indication of recent apolysis) first appeared at 10 h at the anterior-most site and at 12 h at the remaining three sites. Pupal cuticle increased in thickness up to 12 to 14 h and then decreased. Adult procuticle first appeared at 22 h at three sites and at 24 h at the remaining site. Pupal rearing temperature influenced timing of molting fluid secretion. Molting fluid appeared earliest (between 10 and 15 h) in pupae reared at 27 and 32°C, later (between 10 and 20 h) at 22 and 37°C, and latest (between 20 and 25 h) at 17°C.