Non-nutritive sugar feeding alters the genetic profile of diuretic hormones and their receptors in <i>Drosophila suzukii</i> (Diptera: Drosophilidae)

Abstract Non-nutritive sugars such as erythritol and sucralose are active ingredients in artificial sweeteners. In the past decade, research has demonstrated insecticidal properties of non-nutritive sugars across several arthropod species. It is now a prospective chemical control option for spotted-wing drosophila, Drosophila suzukii, one of the most economically important pests of small fruits. D. suzukii die quicker, excrete waste in large amounts, and become desiccated when fed a mixture of erythritol and sucralose. The toxicity of non-nutritive sugars to the fly is not clearly elucidated but is likely due to nutritional and physiological failures associated with an excess fluid excretion and water imbalance, caused a hyperosmotic in the body. The diuretic processes in insects are primarily regulated by 3 neuropeptides: the CAPA hormone, diuretic hormone 31 (DH31), diuretic hormone 44 (DH44). To explore the genetic effects of non-nutritive sugars on D. suzukii, we investigated the genetic regulation of 3 key hormone genes—capa, dh31, and dh44—and their 7 corresponding receptors under different dietary conditions: erythritol + sucrose, sucralose + sucrose, and erythritol + sucralose. Molecular analyses revealed that the expression levels of capa, dh31, dh44, and their receptors were significantly altered in non-nutritive sugar-fed flies compared to the control group fed only sucrose. Through trials testing synergistic effects of peptide injection and non-nutritive sugar consumption, DH44 peptide consistently and significantly increased the mortality of non-nutritive sugar-fed flies across all diet groups. These genetic and physiological findings offer molecular insights for the development of novel pest management strategies targeting D. suzukii.