Age-related fecundity and sex ratio variation in Apanteles galleriae (Hym., Braconidae) and host effect on fecundity and sex ratio of its hyperparasitoid Dibrachys boarmiae (Hym., Pteromalidae)

Abstract

Age-related progeny production and sex ratio of Apanteles galleriae Wilkinson, a koinobiont, solitary, larval endoparasitoid of two lepidopteran species, Galleria mellonella ( L.) and Achoria grisella Fabr., were studied at 25 +/- 1 degreesC, 60 +/- 5% relative humidity, and a photoperiod of 12 : 12 h ( L : D). The effect of host type on fecundity and sex ratio of the hyperparasitoid Dibrachys boarmiae ( Walker), an idiobiont, gregarious pre-pupae or pupae ectoparasitoid on A. galleriae was also investigated. Total progeny produced by A. galleriae showed very little host-dependent variation. The mean total number of offspring produced by a female was 232.6 and 239.7 on G. mellonella and A. grisella, respectively. Progeny production and proportion of females per host by A. galleriae decreased directly with parental age. Fecundity of D. boarmiae on A. galleriae pupae reared on G. mellonella and A. grisella was 3.3 and 2.9 respectively. Host type had no significant influence on progeny production and sex ratio of D. boarmiae.