Effects of different hormones as dietary supplements on biological characteristics of Coccinella septempunctata L.

Abstract

When Coccinella septempunctata L. was fed on an artificial diet, development was prolonged and survival and reproduction were decreased, thus negatively affecting population growth. Juvenile hormone and moulting hormones are important factors in insect reproduction and development. This study aims to screen out the optimal hormones that can solve the problems such as slow population growth of the C. septempunctata during mass rearing, thus improving their effectiveness as a biological control agent. The effects of juvenile hormone analogues and moulting hormones on C. septempunctata larval growth and adult reproduction were investigated by supplementing an artificial diet with different doses of methoprene, kinoprene, juvenile hormone Ш, fenoxycarb and 20‐hydroxyecdysone. Multiple parameters were measured for C. septempunctata including development, survival, pupation, emergence, pre‐oviposition, fecundity and hatching rates. The addition of juvenile hormone analogues to the diet significantly lengthened larval development times and reduced pupation and emergence. Conversely, juvenile hormone analogues significantly shortened pre‐oviposition period, reduced survival and increased fecundity. The shortest pre‐oviposition period was 9.6 days, and the highest oviposition number was 578 eggs in response to 5 μL kinoprene. The highest hatching rate was 66% in 1.7 mg 20‐hydroxyecdysone treatment. The results of this study provide a theoretical basis for hormone selection and dosage in C. septempunctata artificial diets, thus enhancing the survival, pupation and emergence of larvae and improving the fecundity and hatching rate of ladybird adults.

Transcriptomics Provide Insights into the Photoperiodic Regulation of Reproductive Diapause in the Green Lacewing, Chrysoperla nipponensis (Okamoto) (Neuroptera: Chrysopidae)

“…In our recent study, we found that exogenous JH treatment significantly shortened the pre-oviposition period of diapausing C. nipponensis female adults [53]. A similar result has also been observed in the oriental armyworm Mythimna separata and C. septempunctata [54][55][56]. Here, we knocked down the key gene CnJhamt1, involved in juvenile hormone synthesis in diapause-sensitive C. nipponensis during the diapause-sensitive period, and we found that the pre-oviposition period of C. nipponensis was significantly prolonged (Figure 6A), which indicated that the gene has an influence on the reproductive capacity of diapause-sensitive C. nipponensis.…”

Cloning and functional analysis of the juvenile hormone receptor gene CsMet in Coccinella septempunctata

“…We speculated that the decline in egg production and hatching rates of C. septempunctata reared on artificial diets may be caused by downregulation of Met expression. When JH is added to artificial diet, it can significantly improve both egg production and hatching rates ( Cheng et al 2023 ); however, the spatio-temporal expression of Met and regulation of reproduction by Met in C. septempunctata are unclear. In the present study, we utilized the transcriptome database of C. septempunctata to clone the full-length cDNA sequence of Met .…”

Evaluation of Black Soldier Fly Hermetia illucens as Food for Pink-Spotted Lady Beetle Coleomegilla maculata

“…Insects 2023, 14, 902 2 of 12 and more recent work has continued with the aim of discovering more effective diets via the utilization of lepidopterans, dipterans, crustaceans, and juvenile hormones [6][7][8][9][10][11].…”