Enhancing Stored Insect Quality by Inducing Dormancy or Resting States

Jim Crocker
26th May, 2024

Enhancing Stored Insect Quality by Inducing Dormancy or Resting States

Image Source: Natural Science News, 2024

Key Findings

  • The study was conducted at the National Research Centre in Egypt to optimize storage conditions for Trichogramma evanescens wasps
  • Longer incubation periods (48 hours) and lower temperatures (9°C) were more effective in inducing diapause in the wasps
  • Wasps stored for shorter periods (up to 3 months) after longer diapause induction (up to 6 weeks) maintained better efficacy
The National Research Centre recently conducted a study[1] examining the optimal conditions for inducing diapause or quiescence in the parasitic wasp species Trichogramma evanescens Westwood. This research is pivotal for improving the mass rearing and storage of these wasps, which are widely used as biological control agents against various agricultural pests. Trichogramma wasps are beneficial insects that parasitize the eggs of many pest species, making them effective tools for pest management in agriculture. They can enter a dormant state, known as diapause or quiescence, to survive unfavorable conditions such as cold seasons. Understanding how to optimize these conditions can significantly enhance the efficiency and reliability of using Trichogramma wasps in pest control programs. The study aimed to determine the best conditions for inducing diapause in Trichogramma evanescens and to evaluate the impact of these conditions on the efficacy of the stored parasitoids. Four factors were tested: incubation periods (24 and 48 hours), diapause induction temperatures (9 and 11°C), durations of diapause induction (ranging from 0 to 6 weeks), and storage periods (ranging from 0 to 6 months). The findings revealed that both the incubation period and the diapause induction temperature significantly influenced the success of inducing diapause. Longer incubation periods (48 hours) and lower induction temperatures (9°C) were more effective in inducing diapause. Additionally, the duration of diapause induction and the storage period also played crucial roles. Parasitoids that underwent diapause induction for longer durations (up to 6 weeks) and were stored for shorter periods (up to 3 months) maintained better efficacy. These results align with previous studies on Trichogramma species. For instance, research on T. evanescens and T. chilonis demonstrated that parasitized host eggs could be stored at 4°C for up to 30 days without significant loss of performance[2]. This current study extends these findings by showing that diapause induction at specific temperatures and durations can further enhance the storage potential of Trichogramma wasps. The study also builds on the understanding of diapause as a survival strategy. Diapause is a common response to seasonality in many insects, allowing them to withstand adverse conditions[3]. By optimizing the conditions for diapause induction, the researchers have provided valuable insights that could improve the practical application of Trichogramma wasps in pest management. In conclusion, the National Research Centre's study offers significant advancements in the mass rearing and storage of Trichogramma evanescens. By identifying optimal conditions for inducing diapause, this research enhances the potential for using these wasps as effective biological control agents. The findings not only support previous research on Trichogramma storage[2] but also contribute to the broader understanding of diapause regulation and its practical applications in agriculture.

AgricultureBiotechAnimal Science


Main Study

1) Improving quality of stored Trichogramma evanescens (Hymenoptera: Trichogrammatidae) by inducing diapause or quiescence

Published 24th May, 2024


Related Studies

2) Effects of low temperatures on quiescence in Trichogramma evanescens Westwood and T. chilonis Ishii reared on Plodia interpunctella (Hübner): implications for mass rearing.


3) Evolutionary and functional genetics of insect diapause: a call for greater integration.


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