DefinePK

Research Objective

To evaluate the response of gamma irradiation on Sitotroga cerealella (Angoumois grain moth) and Trichogramma chilonis (egg parasitoid) under laboratory conditions, specifically examining the effects on egg viability, parasitism, adult emergence, and longevity.

Methodology

The study involved exposing eggs of S. cerealella (aged 12 and 24 hours) and pupae of T. chilonis to various doses of gamma radiation (35, 55, 65, 75, 95 Gy for eggs; 5, 10, 15, 20 Gy for pupae) and a control group. For S. cerealella eggs, hatching rate and incubation period were recorded. For the interaction between S. cerealella eggs and T. chilonis, parasitism percentage, adult emergence, and adult longevity of T. chilonis were measured. For T. chilonis pupae, adult emergence and longevity were assessed. Experiments were replicated three times for each dose.

Methodology Flowchart

                        graph TD;
    A[Prepare S. cerealella eggs and T. chilonis pupae];
    B[Expose to Gamma Radiation Doses];
    C[Record S. cerealella egg hatching and incubation];
    D[Parasitize irradiated S. cerealella eggs with T. chilonis];
    E[Record T. chilonis parasitism, emergence, and longevity];
    F[Record T. chilonis pupal emergence and longevity];
    G[Analyze Data];
    H[Draw Conclusions and Recommendations];
    B --> C;
    B --> D;
    D --> E;
    B --> F;
    C --> G;
    E --> G;
    F --> G;
    G --> H;                    

Discussion

The findings suggest that gamma irradiation can be used to manage S. cerealella and T. chilonis populations, with lower doses being beneficial for maintaining the quality and viability of the parasitoid and its host for year-round availability in insectaries. The study highlights a dose-dependent response, where increasing radiation levels have detrimental effects on insect development and reproduction.

Key Findings

Lower doses of gamma irradiation (e.g., 35 Gy for eggs, 5 Gy for pupae) generally resulted in higher egg viability, parasitism, adult emergence, and adult longevity for both S. cerealella and T. chilonis. Conversely, higher doses (e.g., 95 Gy for eggs, 20 Gy for pupae) led to significantly lower values for these parameters. Control groups (no irradiation) consistently showed the highest values for all measured parameters.

Conclusion

Lower doses of gamma irradiation are recommended to increase the shelf life of S. cerealella and T. chilonis without significant detrimental effects on the quality of the parasitoid and its host, thereby ensuring year-round availability for research and field releases.

Fact Check

The study exposed S. cerealella* eggs to doses of 35, 55, 75, and 95 Gy.
At a dose of 35 Gy, S. cerealella* eggs showed a hatching rate of 55.3% and an incubation period of 7.06 days.
For T. chilonis* pupae irradiated at 5 Gy, adult emergence was 86.66% and adult longevity was 7.46 days.

Mind Map