Price Briana E, Yoon June-Sun, Choi Man-Yeon, Lee Jana C
Horticultural Crops Research Unit, USDA ARS, Corvallis, Oregon, USA.
Department of Horticulture, Oregon State University, Corvallis, Oregon, USA.
Arch Insect Biochem Physiol. 2022 Feb;109(2):e21860. doi: 10.1002/arch.21860. Epub 2021 Dec 5.
The nonnutritive sugar, erythritol, has the potential to be a human-safe management tool for the small fruits and cherry pest, Drosophila suzukii, or spotted-wing drosophila. Feeding on erythritol decreases fly survival and oviposition by starving and creating an osmotic imbalance in the body. Recently, we demonstrated that erythritol combined with another nonnutritive sugar, sucralose, was fed upon more than erythritol alone and hastens D. suzukii mortality. This suggests that sucralose is a suitable nonnutritive phagostimulant alternative to sucrose. Although promising, the nutritional and physiological impacts of sucralose on D. suzukii are unknown. In this study, we investigated whether sucralose is metabolized or excreted by D. suzukii when fed various erythritol, sucrose, and sucralose formulations. We found that sucralose cannot be metabolized or converted into any nutritional substitutes or storage carbohydrates in D. suzukii. Instead, sucralose molecules were largely accumulated in the hemolymph and slowly excreted from the body, creating a significant osmotic imbalance in D. suzukii. To excrete unused sugars, flies will use their own body fluids to restore homeostasis, resulting in losing a substantial amount of body weight and becoming desiccated in the process. In summary, ingesting sucralose leads to starvation and hyperosmotic pressure in the body, causing a decrease in fitness. With confirmation of sucralose being non-metabolizable and phagostimulative to D. suzukii, the erythritol+sucralose formulation is a promising insecticide for growers to use.
非营养性糖类赤藓糖醇有潜力成为一种对人类安全的管理工具，用于防治小型水果和樱桃害虫铃木氏果蝇（即斑翅果蝇）。取食赤藓糖醇会导致果蝇饥饿，并在其体内造成渗透失衡，从而降低果蝇的存活率和产卵量。最近，我们证明，与另一种非营养性糖类三氯蔗糖结合的赤藓糖醇比单独的赤藓糖醇更受果蝇取食，并能加速铃木氏果蝇的死亡。这表明三氯蔗糖是一种适合替代蔗糖的非营养性摄食刺激剂。尽管前景乐观，但三氯蔗糖对铃木氏果蝇的营养和生理影响尚不清楚。在本研究中，我们调查了给铃木氏果蝇投喂各种赤藓糖醇、蔗糖和三氯蔗糖配方后，三氯蔗糖是否会被其代谢或排泄。我们发现，三氯蔗糖在铃木氏果蝇体内无法被代谢或转化为任何营养替代物或储存碳水化合物。相反，三氯蔗糖分子大量积聚在血淋巴中，并缓慢地从体内排出，在铃木氏果蝇体内造成显著的渗透失衡。为了排泄未使用的糖类，果蝇会利用自身的体液来恢复体内平衡，导致体重大量减轻，并在此过程中变得脱水。总之，摄入三氯蔗糖会导致果蝇饥饿和体内渗透压升高，从而降低其适合度。随着三氯蔗糖对铃木氏果蝇不可代谢且具有摄食刺激作用得到证实，赤藓糖醇 + 三氯蔗糖配方有望成为种植者使用的杀虫剂。
