FOOD MIXING BY GENERALIST GRASSHOPPERS - PLANT SECONDARY COMPOUNDS STRUCTURE THE PATTERN OF FEEDING

Plant secondary compounds can prevent feeding by phytophagous insects or, if ingested, can be poisonous to them, Less attention has been pai d to the additional effects they have on feeding behavior when they ar e only weakly deterrent or not deterrent at all. Experiments were carr ied out on the generalist grasshopper Schistocerca americana. Individu als were presented either with two cakes of high-quality artificial fo od with a single deterrent compound added or with two cakes, each with a different added deterrent compound. The deterrents consisted of sin gle plant secondary compounds that were either marginally or strongly deterrent. There were profound differences in feeding behavior between those individuals given identical and those given different cake type s, including longer feeding bouts on single cakes when a choice of dif ferent cake types was available, The behavioral effects demonstrate th at the presence of secondary compounds in one food can influence the p atterns of feeding on other available foods and suggest that such chem icals could impact foraging activities in a complex manner.