Persistence of Carbohydrate Availability Shapes Longevity and Reproductive Performance of Trichogramma chilonis Ishii (Hymenoptera: Trichogrammatidae)

This study investigated whether carbohydrate source and the persistence of nutrient availability influence the life-history and reproductive performance of Trichogramma chilonis. Seven experimental treatments were evaluated: continuous supply of 20% honey–water (HWC), one-time supply of 20% honey–water with the nutrient source retained throughout the experiment (HW1C), one-time supply of 20% honey–water followed by removal of the nutrient source on Day 2 (HW1), continuous supply of 20% sucrose (SWC), one-time supply of 20% sucrose with the nutrient source retained throughout the experiment (SW1C), one-time supply of 20% sucrose followed by removal of the nutrient source on Day 2 (SW1), and a water-only control (CK). Unlike previous studies that primarily compared carbohydrate types or carbohydrate-fed and unfed parasitoids, the present study specifically assessed the importance of persistent nutrient access. Nutrient-supply treatments significantly increased adult longevity and lifetime parasitism capacity compared with the water-only control. SW1C, SWC, HWC, and HW1C showed statistically comparable longevity and lifetime parasitism capacity and performed better than treatments in which the nutrient source was removed and the water-only control. Daily parasitism was highest during the early adult period and declined with age, although nutrient-fed females maintained parasitism for a longer period. Female progeny ratio varied among experimental treatments, while offspring emergence remained high and statistically similar across the experimental treatments, ranging from approximately 85% to 89%. Overall, honey–water and sucrose diets improved the adult performance of T. chilonis without reducing offspring viability, supporting their use in mass-rearing and biological-control programs.