Meeting Abstract

70.3  Monday, Jan. 6 08:30  Metabolic Demand of Ovoviviparous Reproduction in the Guyana Orange Spotted Cockroach Blaptica dubia MALLERY JR., C.S.*; DZIALOWSKI, E.M.; University of North Texas christophermallery@my.unt.edu

Cockroaches display a variety of reproductive modes, from viviparity to oviparity to ovoviviparity. The Guyana Orange-spotted Cockroach, Blaptica dubia, is an ovoviviparous species that lays an egg sac (ootheca), which is retracted into a brood sac for the duration of incubation, and subsequently gives live birth to nymphs (observed at day 46 in this study). Ovoviviparity presents a tradeoff between protecting the eggs and providing a proper hygric environment, and utilizing excess resources not necessary in the more common insect reproductive mode, oviparity. We studied changes in metabolic rate of developing embryos and gravid females to assess the extent of this increased energy expenditure. Gravid female cockroaches increased in mass throughout the duration of incubation, and metabolic rate per unit mass of the females increased. This increase is not exclusively due to females facilitating gas exchange of the developing embryos, as the metabolic demand of eggs increased throughout development but did not fully account for the female’s metabolic rate increase. This increase in metabolic rate of female B. dubia during the course of incubation can serve as a measure of the reproductive tradeoff to maintain the eggs in a brood sac.