A BIMODAL RESPONSE TO DIETARY SUGARS BY AN INSECT

Abstract

Dietary concentrations of glucose, fructose, or sucrose had a pronounced and quantitatively measurable effect on the feeding behavior of newly hatched, previously unfed larvae of the European corn borer, Pyrausta nubilalis. Duration of continuous feeding tended to be in direct proportion to sugar concentration of the diet. Responses to glucose concentrations were in agreement with the Weber-Fechner law above a response threshold of about 0.001 [image]. The insect displayed a bimodal response in that glucose concentrations below 0.001 [image] but above 0.0002 [image] elicited shorter feeding times than did control diets containing no glucose. Similar negative responses were observed with fructose and sucrose.