Effects of Temperature on the Life Table Parameters of Trichogramma zahiri (Hymenoptera: Trichogrammatidae), an Egg Parasitoid of Dicladispa armigera (Chrysomelidae: Coleoptera)

Abstract

The influence of different temperatures on biological parameters of native strains of Trichogramma zahiri Polaszek (Hymenoptera: Trichogrammatidae), an egg parasitoid of rice hispa, Dicladispa armigera (Olivier) (Chrysomelidae: Coleoptera), was evaluated in the laboratory on its host. The key biological parameters of the parasitoid T. zahiri in relation to temperature were investigated to find out its candidature as a potential biological control agent of rice hispa. The highest number of eggs parasitized by T. zahiri was 15.7 eggs per female at 26 °C, which differed significantly from those at 18, 22, 30, and 34 °C (P < 0.05). Development duration and longevity of T. zahiri decreased as temperature increased. Fecundity differed significantly at all constant temperatures. Emergence rates decreased at both high (34 °C) and low ( < 26 °C) temperatures. Female-biased sex ratio ranged from 54 to 70% at all constant temperatures. The lower temperature threshold for T. zahiri was 6.2 °C for males and 6.95 °C for females. The upper threshold temperatures were 35.82 and 35.87 °C for males and females, respectively. Net reproductive rate (R0) was highest at 26 °C compared with other temperatures. Mean cohort generation time (tG) and population doubling time (tD) decreased as temperature increased from 18 to 30 °C. The daily intrinsic rate of increase (rm) and finite rate of increase (λ) were positively correlated with temperatures ranging from 18 to 30 °C and then decreased at 34 °C. The relevance of our results is discussed in the context of climatic adaptation and biological control.

Biological parameters and thermal requirements of Trichogramma pretiosum reared on Helicoverpa armigera eggs

“…Cabezas et al (2013) found significant values for emergence when evaluating three strains of T. pretiosum on eggs of Spodoptera cosmioides (Walker, 1858) (Lepidoptera: Noctuidae) at 25°C. As observed in the study herein, Bari et al (2015) also observed smaller emergence rates in extreme temperatures for T. zahiri (Polaszek, 2002) (Hymenoptera: Trichogrammatidae) on eggs of Dicladispa armigera (Oliver, 1808) (Coleoptera: Chrysomelidae).…”

“…Similar results were found by Bari et al (2015), who verified low percentage of parasitism at the temperatures of 18°C and 34°C, when evaluating the performance of Trichogramma zahiri (Polaszek, 2002) (Hymenoptera: Trichogrammatidae) on eggs of Dicladispa armigera (Oliver, 1808) (Coleoptera: Chrysomelidae). Foerster et al (2014) obtained a higher percentage of parasitism of T. pretiosum and T. atopovirilia on eggs of Anticarsia gemmatalis (Hübner, 1818) (Lepidoptera: Noctuidae) at the temperature of 26°C.…”

Differences in Gall Induction of Flower-like Galls on Haloxylon by Psyllids (Hemiptera: Aphalaridae), and the Emergence of Corresponding Parasitoids

“…When the temperature ranged from 20 • C to 38 • C, the eclosion rate of parasitoids increased first and then decreased, while their lifespans decreased gradually. This was consistent with the report about the composition of Torymus parasitoids found in the galls of chestnut trees and other related studies on parasitoids [62][63][64]. However, the biological characteristics (eclosion rate, the sex ratio and longevity) of parasitoids were influenced by many other internal factors (female wasp nutrition, egg nutrition, and ovipositing age of female wasps) and external factors (temperature, humidity, and light cycle) [33,65].…”

Evaluating the Potential of Using Spodoptera litura Eggs for Mass-Rearing Telenomus remus, a Promising Egg Parasitoid of Spodoptera frugiperda

“…It was reported previously that T. remus presents poor parasitism at extreme temperatures [ 31 ]. The decreased fecundity of female parasitoids at high temperatures is a consequence of a reduced lifespan [ 39 ], which implies that temperature optimization is vital for the build-up of a large-scale population. In addition, eggs lose water faster at a high temperature, which may explain the observed decrease in the parasitism capacity [ 31 ].…”