Nutritional interactions in insect gall maker/host plant systems in the Cerrado

Abstract

 The applicability of the nutritional hypothesis for the gall maker/ host plant systems in the Cerrado was valued on this paper. Nitrogen, sugars, tannin and carbon were quantified and the C/N relation of the non-infested leaves, the infested leaves and galls of Anadenanthera peregrina var. falcata and Duguetia furfuracea was determined. The gall makers/plant host systems presented different activities according to the analyzed parameters. The leaves galls of A. peregrina var. falcata presented a low content of nitrogen and a high percentage of sugars and tannin. Only in December the percentage of carbon in the non-infested leaves and galls was significantly higher than the infested ones; the gall maker (Diptera: Cecidomyiidae, Schizomia) influenced in the chemistry of the vegetal tissues, diverting substances from the leaves to the galls. The highest values in the relation C/N for the A. peregrina var. falcata were observed in the galls from December to February and in April and May. The highest tannin values of D. furfuracea were observed in both non-infested and infested leaves; we didn’t observe a pattern to explain the relationship C/N in this species. The gall-inducing insect is Bruggmanniella duguetiae (Diptera: Cecidomyiidae). The obtained results demonstrated that the nutritional hypothesis is not applied to the Cerrado species A. peregrina var. falcata and D. furfuracea.