Offspring in Response to Parental Female Densities in the Fruit Fly Parasitoid DIACHASMIMORPHA LONGICAUDATA (Hymenoptera: Braconidae: Opiinae)

• Published in: The Florida entomologist 2008-12, Vol.91 (4), p.628-635
• Main Authors: Paranhos, Beatriz J, Costa, Maria De Lourdes Z, Ovruski, Sérgio M, Alves, Renata M, Blummer, Lucimara, Walder, Júlio M. M
• Format: Article
• Language: English
• Subjects: Age; Biological control; biological control agents; Braconidae; Brazil; Ceratitis capitata; Control; Diachasmimorpha longicaudata; Eggs; Fecundity; Female animals; females; Fruit flies; Growth; Hymenoptera; Insect larvae; Insect pests; insect rearing; insect reproduction; Male animals; medfly; Mortality; Observations; offspring sex ratio; Parasite hosts; Parasitism; parasitism efficiency; Parasitoids; parental sex ratio; population density; Progeny; Ramadan; Sex ratio
• ISSN: 0015-4040; 1938-5102
• DOI: 10.1653/0015-4040-91.4.628

As part of an evaluation of the braconid parasitoid Diachasmimorpha longicaudata (Ashmead) as a biocontrol agent of Ceratitis capitata (Wiedemann) in Brazil, the aims in the current study were to find the best parental ratio of females to males in the rearing cages in order to get the highest female biased offspring in the parasitoid rearing process, and to verify the parasitism efficiency on C. capitata according to parental female densities. Three treatments were assessed: T1 (20 females: 20 males), T2 (60 females: 20 males) and T3 (100 females: 20 males). Ten late-third instars of C. capitata were offered daily to each female parasitoid from the 1st to the 12th d of age. The parental female productivity, fecundity, offspring sex ratio, percentage of parasitoid emergence, and daily mortality of parental females and males at different female/male densities were evaluated. The results indicated that numbers higher than 20 parental females did not affect offspring sex ratio, overall offspring production, nor the percent parasitism. Female biased offspring occurred in all three parental female/male ratios analyzed in this study, except that predominately males developed from parasitoid eggs laid in the age interval 1-2 d post emergence. Higher parasitoid female productivity and fecundity were found at the 1:1 female/male per cage density whereas lower productivity and fecundity were recorded at the 5:1 female/male ratio. Higher female/male ratio in the parental cages increased the mortality rate of females but did not influence the number of parental male deaths. The results may facilitate advancement of an optimum mass-rearing system to aid in control of C. capitata in Brazil.