Effect of cold storage temperature on quality of the parasitoid, Trichogrammatoidea bactrae Nagaraja (Hymenoptera: Trichogrammatidae)

Abstract

This study was designed to find out the optimum cold storage temperature (4, 7, and 10 °C) and storage period (1–16 weeks) of 3 different immature developmental stages (2, 4, 6 days post parasitism) of the egg parasitoid, Trichogrammatoidea bactrae Nagaraja (Hymenoptera: Trichogrammatidae) to produce high-quality individuals to be utilized. Also, the effects of cold storage on parasitoids’ fitness in terms of parasitism percentage, developmental period, adults’ emergence percentage, female percentage, and longevity (fed and un-fed) of parents and F1 progeny were investigated. The obtained results revealed that T. bactrae larvae (2-day post parasitism) could be stored for at least 7 weeks at 10 °C, with least changes in their fitness in both the parents and F1 progeny, followed by 7 °C, whereas storage at 4 °C was the fatal temperature in this early stage of parasitoid with a maximum mortality rate that extended to the next generation (F1). Furthermore, female biased sex ratios were observed at all storage temperatures in the parental and F1 generations but with different values. After a cold exposure of pre- and pupal stages (4, 6 days post parasitism) of the parasitoid at 7 °C, adults’ emergence percentage in the parents was low, but the biological performance in progeny was great. In addition, these late stages could be stored for a short period up to 4 weeks at 10 °C with highest performances in both generations, followed by 7 °C. Ten degrees Celsius proved to be the most suitable storage temperature at different parasitoid ages (larvae, pre-pupae, and pupae). Only the larval stage could continue up to 16 weeks of cold storage, and hence, it can be recommended for a short- and/or a long-term storage period.

The impact of cold storage durations on Trichogramma evanescens (Westwood) (Hymenoptera: Trichogrammatidae) during their pupal stage

“…This may be because of the cold temperatures, which decrease the quality and vitality of parasitized eggs. Our results were in harmony with the findings of El Khayat et al, 2001 , Farid et al, 2001 , Chen et al, 2008 , Mohamed and El-Heneidy, 2020 they found that the adult female’s percentages were significantly influenced by the cold storage durations. In comparison with the non-cold-stored parasitized eggs, the female’s percentage declined by 4.01, 8.22, 13.26, 18.60, 25.14, 25.43, 28.13, 28.20, 29.97, and 30.94% in cold storage parasitized eggs for 3, 6, 9, 12, 15, 18, 21, 24, 27, and 30 days, respectively ( Table 2 ).…”

“…Also, cold storage durations had a clear negative impact on the emergence rate with T. nerudai ( Tezze and Botto, 2004 ), and T. cordubensis ( Ventura Garcia et al, 2002 ). The reduction in the percentage of adult females increased by extended cold storage times ( El Khayat et al, 2001 , Mohamed and El-Heneidy, 2020 ). Moreover, the longevity of adult females of T. evanescence decreased as the storage durations extended at 4 °C ( Karabörklü and Ayvaz, 2007 ).…”

Optimal cold storage protocol for Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae), a biological control agent for coleopteran pests in stored products

“…By contrast, adverse effects occurred with egg hatching of H. axyridis following long‐term cold storage, although the egg production of the F 1 offspring remained unaffected 40 . When exposed to lower temperatures, the mortality of Trichogrammatoidea bactrae (Nagaraja) (Hymenoptera: Trichogrammatidae) larvae escalated significantly, and these detrimental effects were inherited 41 . DNA methylation may act as a pivotal mechanism that transmits the consequences of chilling damage from the maternal generation to the F 1 generation 42 …”

“…40 When exposed to lower temperatures, the mortality of Trichogrammatoidea bactrae (Nagaraja) (Hymenoptera: Trichogrammatidae) larvae escalated significantly, and these detrimental effects were inherited. 41 DNA methylation may act as a pivotal mechanism that transmits the consequences of chilling damage from the maternal generation to the F 1 generation. 42 In conclusion, our study suggests that Anisopteromalus calandrae can be successfully maintained in long-term cold storage at 13 °C for up to 90 days without considerable undesirable effects on their suitability.…”

Effects of transgenerational photoperiod experience on the reproduction and development of Anastatus orientalis, an egg parasitoid of the spotted lanternfly

“…Storage time plays a key role in the production of Anastatus species, in that a longer storage time can provide a flexible supply of parasitoids for their timely and urgent field release in biological control programmes. The most commonly used preservation method for an egg parasitoid is cold storage (45)(46)(47)(48). However, this method not only fails to guarantee its shelf life but also affects the quality of natural enemy products (23,49,50).…”