Life table of Orius insidiosus (Hemiptera: Anthocoridae) feeding on Sitotroga cerealella (Lepidoptera: Gelechiidae) eggs

Abstract

To use a natural enemy to control an insect pest, it is important to determine the biological parameters of the native populations of the predator. The goal of this study was determinate the biological parameters of O. insidiosus fed on Sitotroga cerealella eggs. A batch of 225 O. insidiosus eggs were laid into bean pods. The bean pods were kept in glass jars, and the eggs and first instar nymphs were counted daily. All nymphs were extracted and individualized in Petri dishes. The presence/absence of exuvie was observed daily as a way to assess the emergence of adults from the nymphal stage. Seventeen adult couples were placed into Petri dishes with a segment of bean pod. The bean pod segments were extracted and replaced daily, counting the number of eggs present on the pods. The life cycle, survival percentage, sex ratio, male/female longevity, pre ovoposition, ovoposition and post ovoposition periods were determined. Finally, fertility life table parameters were estimated. The nymphal development time was 12.0 ± 0.22 days, with 80.47 % ± 3.23 survival, while the total development time was 15.0 ± 0.23 days, with 66.67 % ± 1.90 survival. Of the total adults that emerged, 30.95 % ± 2.38 were females. The female sex ratio was 0.75, and the oviposition period was 0.86 ± 9.21 days with a total fertility of 60.29 ± 7.39 eggs. The data estimated from the fertility life table were: Ro: 28.26, rm: 0.14, T: 24.26, λ: 1.13 and DT: 5.01.

Effect of Two Oviposition Feeding Substrates on Orius insidiosus and Orius tristicolor (Hemiptera: Anthocoridae)

“…The lack of humidity is the principal cause of mortality in the immature stages of O. insidiosus (Schmidt et al 1998). Tommasini et al (2004) and Avellaneda et al (2016) obtained a total time of immature development of O. insidiosus on bean pods similar to that we observed in the current study, when this species was fed with F. occidentalis adults (14.1 d) or with E. kuehniella eggs (15 d). In contrast, for O. tristicolor, Pinto et al (2004) and Hokkanen et al (2002) reported higher values on bean pods than those found in the current study, with a duration from egg to adult of 33.3 and 32 d at 26 °C, respectively, when this species was fed with F. occidentalis and Tetranychus urticae Koch (Acarina: Tetranychidae).…”

“…The duration of the egg development of O. insidiosus on bean pods observed in the current study was similar to that reported by van den Meiracker (1999) (4.6 d) and Tommasini et al (2004) (4.2 d), who studied this species on the same vegetable substrate. Our findings were similar to data reported for O. tristicolor by Askari and Stern (1972) (5 d) at 25.5 °C on petioles from bean leaves; however, the findings were different than that reported by Avellaneda et al (2016) when they evaluated O. insidiosus on bean pods. Care must be taken when comparing results from different authors because of the influence exerted by the different experimental methods used, the variability in the populations of predators used in each study, or the previous history of the offspring from which adults used for the oviposition were extracted (Iranipour et al 2009;Avellaneda et al 2016).…”

“…Pods and peppers were gathered into 7 groups of 30 eggs each. Each group was considered a replication, and the pods and peppers from each replication were put in plastic boxes (Biriden, Montevideo, Uruguay) (20 cm in diam) covered with polyethylene extendible film (Naka SA, Montevideo, Uruguay) and kept until the nymphs hatched, following the procedure reported by Avellaneda et al (2016).…”

“…Bean pod sections and pepper fruits were removed daily and replaced by fresh ones until the death of the female. In case the male died before the female, he was quickly replaced (Avellaneda et al 2016).…”