Location: Southern Insect Management ResearchTitle: Continuous rearing on Ephestia kuehniella reshaped quality of the parasitoid wasp Trichogramma brassicae (Hymenoptera: Trichogrammatidae)
|GHAEMMAGHAMI, EHSAN - Tarbiat Modares University|
|FATHIPOUR, YAGHOUB - Tarbiat Modares University|
|BAGHERI, ABDOOLNABI - Tarbiat Modares University|
|TALEBI, ALI ASGHAR - Tarbiat Modares University|
|Reddy, Gadi V.P.|
Submitted to: Journal of Asia-Pacific Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/19/2021
Publication Date: 3/4/2021
Citation: Ghaemmaghami, E., Fathipour, Y., Bagheri, A., Talebi, A., Reddy, G.V. 2021. Continuous rearing on Ephestia kuehniella reshaped quality of the parasitoid wasp Trichogramma brassicae (Hymenoptera: Trichogrammatidae). Journal of Asia-Pacific Entomology. 24:1-9. https://doi.org/10.1016/j.aspen.2021.02.013.
Interpretive Summary: Egg parasitoids, especially trichogrammatid species, are among important natural enemies because of their important role in the timely control of insect pests. The aim of this study was to evaluate the quality and performance of Trichigramma parasitoid reared on Mediterranean flour moth for over 45 generations using two-sex life table and parasitism parameters. The objectives of quality control programs are to test the quality of mass-reared organisms to ensure they have an acceptable level of performance under field conditions. The overall quality of an organism is defined as the ability to function as intended after release. From our results, we can say that continuous mass rearing of Trichogramma led to poor quality of the laboratory-reared insects, especially after G20. Regarding the moth, the negative effects of long-term rearing was revealed after G15. Reduced quality of parasitoid was visible in traits that are ecologically important for parasitoids after they are inundatively released. These undesired effects can be reduced by setting a maximum number of generations of mass rearing before switching the parasitoids to different hosts or renewing the colony with field stock.
Technical Abstract: Continuous mass rearing of Trichogramma brassicae (Bezdenko) at commercial mass rearing insectaries may affect both quality and performance of natural enemies. In the present study, we studied the quality and performance of a colony of T. brassicae reared for over 45 generations (G) on Ephestia kuehniella Zeller using two-sex life table parameters and parasitism capacity. Our results 22 revealed that although different generations showed no significant difference in terms of female longevity or total life span until G35, G5 and G10 had the highest values of fecundity, gross reproductive rate (GRR), net reproductive rate (R0), intrinsic rate of natural increase (r), and finite rate of increase ('). No significant difference in male adult longevity was found among different generations. The longest and shortest mean generation times (T) were found in G10 (13.65 ± 2.31 d) and G45 (13.25 ± 3.37 d), respectively. The finite rate of parasitism (') ranged from 0.355 ± 2.332 host/parasitoid/day in G5 to 0.242 ± 0.017 host/parasitoid/day in G45. However, ' did not show any significant difference until G20. These results indicate that T. brassicae wasps held under continuous laboratory rearing declined in quality after 20 generations, and therefore periodical rejuvenation of the colony by adding feral parasitoids is strongly recommended.