Sexual ratio modulation of Campoletis flavicincta (Hymenoptera: Ichneumonidae) in artificial rearing

Abstract

Abstract - The objective of the present study was to evaluate laboratorial proceedings able to modify the sexual ratio of Campoletis flavicincta (Hym., Ichneumonidae) in mass rearing. Couples of C. flavicincta, with known age, had been individualized and kept in controlled conditions. Larvae of Spodoptera frugiperda (Lep., Noctuidae) were offer to the parasitoids, in the following proceedings of rearing, with reference, between parenthesis, to the obtained sexual ratio: couples formed 24 hours before being larvae offered (0,18) and without that previous period (0,20); offering larvae of 2nd (0,19) or 3rd instar (0,18); and female age from the parasitoids couples: 0-2 days (0,19), between 3-6 days (0,22), from 7-10 days (0,20) and higher than 10 days (0,13). The results did not differ significantly by chi-square test at 5% significance. A complementary assay was carried out, congregating the conditions that had propitiated the higher absolute ratios of females: pairs formed at the moment of larvae offering, larvae of 2nd instar of S. frugiperda and parasitoid females with age between 3 to 6 days. In these conditions, an average sexual ratio of 0,41 was obtained, without modifying the parasitoid biological characteristics.