Gradually Increasing the Temperature Reduces the Diapause Termination Time of Trichogramma dendrolimi While Increasing Parasitoid Performance

Abstract

Trichogramma dendrolimi Matsumura is widely used as a biological control agent of many lepidopteran pests. Diapause has been used as an effective method to preserve the Trichogramma products during mass rearing production. However, it currently takes at least 70 days to break diapause, and we tested whether gradually increasing the temperature instead of using constant temperature could reduce the time of diapause termination and offer a higher flexibility to Trichogramma producers. The diapause termination rates of individuals kept at different conditions were measured, and five groups for which diapause termination rate reached the 95% were selected to test five biological parameters, including the number of eggs parasitized, the parasitism and emergence rates, the female sex ratio, the wing deformation rate, and the parasitoid longevity. Compared to the currently used procedure (70 days at 3 °C), treatments with at least two different temperatures resulted in higher parasitism and emergence rates while keeping the other parameters constant. The treatment that consisted of at least two different temperatures preceded by only 55 days of induction period had the highest population trend index, meaning that the population under these conditions grows more rapidly. Our results demonstrate that gradually increasing temperature allows T. dendrolimi to complete diapause earlier than at present while increasing its potential pest control capacity and providing additional flexibility in mass production of T. dendrolimi.

Genome Assembly and Comparative Analysis of the Egg Parasitoid Wasp Trichogramma dendrolimi Shed Light on the Composition and Evolution of Olfactory Receptors and Venoms

“…Among the commonly used Trichogramma species, T. dendrolimi is one of the most successfully industrialized Trichogramma species used to control agricultural and forestry pests because of its broad distribution, the wide host range and optimized mass-rearing method on eggs of the Chinese oak silkworm, A. pernyi [ 4 , 9 ]. So far, a number of studies have provided insight into the biology and ecology of T. dendrolimi, leading to successful biological control in the field [ 4 , 6 , 9 , 74 ]. However, the genome information of this important Trichogramma species is lacking and restricts further exploration of the molecular mechanism underlying its host recognition and parasitism of T. dendrolimi .…”

Time-Series Transcriptomic Analysis Reveals the Molecular Profiles of Diapause Termination Induced by Long Photoperiods and High Temperature in Chilo suppressalis

“…Therefore, many insects have evolved to utilise the photoperiod for not only inducing of diapause but also for terminating it [ 3 ]. Although not as steady as the photoperiod and temperature, as mentioned earlier, it also plays an important role in the termination of diapause [ 4 , 12 , 13 ].…”