Effects of long-term cold storage on maternal and progeny fitness of laboratory-reared Harmonia axyridis adults

• Published in: BioControl (Dordrecht, Netherlands) Netherlands), 2022-08, Vol.67 (4), p.395-405
• Main Authors: Sun, Yuan-Xing, Hao, Ya-Nan, Zhou, Jing-Jiang, Liu, Chang-Zhong, Wang, Sen-Shan
• Format: Article
• Language: English
• Subjects: Adults; Agriculture; Animal Biochemistry; Animal Ecology; Artificial diets; Beetles; Behavioral Sciences; Biological control; Biomedical and Life Sciences; Biotechnology industry; Carotene; Cold storage; Coleoptera; Eggs; Entomology; Fecundity; Females; Fertility; Harmonia axyridis; Insects; Laboratories; Life Sciences; Mass rearing; Natural enemies; Nutrition; Offspring; Oviposition; Plant Pathology; Progeny; Survival; Trehalose; β-Carotene
• ISSN: 1386-6141; 1573-8248
• DOI: 10.1007/s10526-022-10144-8

Long-term cold storage is a commonly used technique in mass rearing of natural enemies, but it brings a diversity of negative effects, especially for the laboratory-reared biocontrol agents. Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is an important natural enemy of aphids. In this study, the laboratory-reared H. axyridis adults were stored at 6 °C for up to 120 days, and the accompanying effects on maternal and progeny fitness were evaluated and compared with the non-stored beetles (control). Before storage, the newly emerged adults were fed with β-carotene-amended artificial diet for ten days and then acclimated at 15 °C for two days. The mass and trehalose content of the beetle were inversely proportional to the storage duration. The survival rates of the cold-stored beetles decreased as the storage duration increased. However, the survival rates were still above 50% after 120 days in storage (DIS-120). The DIS-120 beetles had a similar fecundity but a significantly longer pre-oviposition period than the control beetles. The egg hatch rates of the DIS-120 beetles were above 60% during the first six days and then dramatically decreased to near zero after day 13. However, the egg viability of the fertility-reduced beetles could be partially restored to approximately 40% by re-mating with non-stored partners. The F1 offspring of the DIS-120 beetles also had a sustained high fecundity but significantly lower egg hatch rate than the F1 offspring of the control beetles. This study demonstrated that the laboratory-reared H. axyridis could be cold stored for approximately 120 days, and their reproductive capability was still acceptable.