Biology, Thermal Requirements, and Fertility Life Table of Strains of Trichogramma foersteri (Hymenoptera: Trichogrammatidae) in Palpita forficifera (Lepidoptera: Crambidae).

Trichogramma foersteri Takahashi is a parasitoid recently identified in eggs of Palpita forficifera Munroe, considered the main pest of the olive tree in Brazil. The efficiency of a parasitoid is conditioned to several factors such as the temperature. The objective was to study the biology of the immature and adult phases at different constant temperatures (10, 15, 20, 25, and 30 °C), determine thermal requirements, and to elaborate a fertility life table for five strains (R1, R2, R3, R4, and R5) to T. foersteri. At 10 °C, there was no development of T. foersteri. The duration of the egg-adult period (days) was inversely related to temperature, ranging from 32 to 34 days (at 15 °C) to 6.5 to 7.5 days (at 30 °C). The thermal range evaluated did not influence parasitism (parasitism > 57%) and the sex ratio (sr > 0.74). The base temperature (Tt) was similar for all strains (approximately 12 °C), corresponding to a thermal constant (K) of 120.48 to 145.13 degree days. For the adult stage, T. foersteri had the highest rate of parasitism (> 48%) to 15 °C. The emergence rate ranged from 75 to 100%. The thermal range did not influence the sex ratio of the lines (sr > 0.70), but reduced the longevity from 50 days (at 15 °C) to 6 days (at 30 °C). Regarding the fertility life table, all strains of T. foersteri showed biological potential of development and growth in eggs of P. forficifera in the thermal range of 15 to 30 °C, important information for the establishment of biological control programs.

Effects of Extrinsic, Intraspecific Competition and Host Deprivation on the Biology of Trichopria anastrephae (Hymenoptera: Diapriidae) Reared on Drosophila suzukii (Diptera: Drosophilidae).

The pupal parasitoid Trichopria anastrephae Lima (Hymenoptera: Diapriidae) shows potential to control Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), and understanding the behavior of this parasitoid in challenging environments is important to obtain a higher efficiency in mass rearing and in biological control programs. This study aimed to verify the effects of extrinsic intraspecific competition and the absence of host on the parasitism of T. anastrephae in D. suzukii pupae. Therefore, to evaluate the parasitism of T. anastrephae under intraspecific competition, groups of 20 pupae (24 h old) of D. suzukii were offered for different densities of parasitoids (1, 3, 5, or 10 couples) during a 7-day period. Whereas to evaluate the effects of host deprivation on parasitism of T. anastrephae, we tested different treatments: T1-no deprivation, T2-complete deprivation, T3-deprivation every other day, T4-deprivation for 3 days, and T5-deprivation for 7 days. The increase of density of parasitoids resulted in an increase of oviposition scars on pupae and a longer biological cycle, suggesting the occurrence of superparasitism. Increased density also resulted in a higher percentage of attacked pupae, but did not affect parasitoids emergence nor sex ratio. Host deprivation affected number of parasitized pupae, number and sex ratio of offspring, and the longevity of females. Based on our findings, competition among females do not impair offspring viability, and host deprivation for a period up to 7 days do not influence parasitism capacity, indicating that it can be used as a pre-release strategy.