The role of the sugar receptor IR60b for Drosophila melanogaster: A hypothesis

In a recent paper, Joseph and colleagues (Joseph et al., 2017) have characterized the selective sucrose receptor IR60b in Drosophila, and proposed that it serves to limit sucrose consumption, and thus to prevent overfeeding. Here, we propose an alternative hypothesis for this sucrose receptor. Adult fruit flies feed by excreting saliva onto the food, and imbibing the predigested liquefied food, or by filling the crop, where the food is predigested. Enzymes in the saliva hydrolyse starch and disacharides into absorbable monosacharides. Premature ingestion into the midgut would not give the enzymes in the saliva enough time to predigest the food. Thus, IR60b might be used as a sensor to monitor the digestive state of external food or crop content: when disaccharides (sucrose) concentration is high, ingestion is inhibited, preventing the malabsorption of sucrose in the gut.

The role of the sugar receptor IR60b for Drosophila melanogaster: A hypothesis

In a recent paper, Joseph and colleagues (Joseph et al., 2017) have characterized the selective sucrose receptor IR60b in Drosophila, and proposed that it serves to limit sucrose consumption, and thus to prevent overfeeding. Here, we propose an alternative hypothesis for this sucrose receptor. Adult fruit flies feed by excreting saliva onto the food, and imbibing the predigested liquefied food, or by filling the crop, where the food is predigested. Enzymes in the saliva hydrolyse starch and disacharides into absorbable monosacharides. Premature ingestion into the midgut would not give the enzymes in the saliva enough time to predigest the food. Thus, IR60b might be used as a sensor to monitor the digestive state of external food or crop content: when disaccharides (sucrose) concentration is high, ingestion is inhibited, preventing the malabsorption of sucrose in the gut.