To effectively address health issues caused by excessive sugar intake， it is crucial to explore the selection preferences and perception mechanisms of sweeteners. This study used Drosophila melanogaster (black-bellied Drosophila) as a model organism to investigate the specificity of sweet taste perception receptor mechanisms by assessing Drosophila' preferences for caloric sugars (sucrose， fructose， glucose) and non-caloric sugar substitutes (sorbitol). The results showed that， compared to sorbitol， caloric sugars stimulated female Drosophila to lay more eggs and exhibited significant oviposition site preferences. Considering the sweet taste receptor Gr5a， it was found that this receptor played a critical role in the perception and behavioral regulation of low-concentration sweet substrates. In high-concentration sweet substrates， even when the function of Gr5a was impaired， fruit flies could still perform limited oviposition， suggesting the presence of other compensatory perception mechanisms. These diverse perception mechanisms enabled animals to more effectively select foods that meet their needs in their environment， optimizing nutritional choices. This study revealed the perceptual and behavioral response mechanisms of Drosophila in a complex sugar environment， providing scientific evidence for the application of sugar substitutes in food and offering new perspectives and theoretical support for broader sugar reduction strategies and healthy eating research.