Host preference and fertility life table of Campoletis sonorensis (Cameron) (Hymenoptera: Ichneumonidae) as a larval endoparasitoid of the cabbage looper, Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae)

From the evaluation of 2-8 day-old larvae of Trichoplusia ni as a host of Campoletis sonorensis, the early second larval instar (3-5 day-old larvae) has been found as the more susceptible stage in the population dynamics regulation of this host. The higher suitability of this stage results in more larvae being parasitised, a higher rate of parasitoid emergence, a higher rate of female emergence, a lower rate of immature parasitoid mortality and a longer development time. The reproduction and the fertility life table parameters of a 12 four day-old female cohort of Campoletis sonorensis has been determined on 4 day-old Trichoplusia ni larvae as host. C. sonorensis females have a mean longevity of 34.5±2.8 days), a mean oviposition period of 22.7±1.9 days), a constant oviposition period of 15.9±1.3 days) and a long post-oviposition period of 11.9±2.2 days). The mean realised fecundity and the mean fertility were 66.92±7.8 and 60.42±7.8 parasitoids per female, respectively. The finite rate of increase (ë) was 1.27 female parasitoids per day, the population multiplied to 60.41 times in a mean generation time of 17.09 days and the intrinsic rate of increase (rm), 0.24 per female parasitoid per day, was larger than those obtained for T. ni by Zote et al (2006).