VARIABILITY IN FLAVONOID COMPOUNDS OF 4 TRIBULUS SPECIES - DOES IT PLAY A ROLE IN THEIR IDENTIFICATION BY DESERT LOCUST SCHISTOCERCA-GREGARIA

We examined how variability in phenolic metabolism of four closely rel ated Tribulus taxa might affect palatability to Schistocerca gregaria. Plants were collected in the Mauritanian breeding areas of the locust . Eighteen Ravonoids (caffeoyl derivatives, quercetin glycosides, incl uding rutin, and kaempferol glycosides) were detected with high-perfor mance liquid chromatography in leaf extracts. Principal component anal ysis (PCA) differentiated relative abundance of flavonoids of Tribulus terrestris from T. longipetalus, T. ochroleucus, and T. bimucronatus. Flavonoid content of T. terrestris leaves varied between northern and southern Mauritanian sites. Dual choice tests with plants whose flavo noid profiles had been determined previously were analyzed by multiple regression. The data suggest that the desert locust prefers T. terres tris plants rich in quercetin glycosides.