We tested the preference prediction of plant vigor hypothesis by examining the relationship between gall occurrence and leaf size. We also examined the effect of galls on leaf asymmetry, which is a measure of developmental instability. Gall occurrence did not increase with leaf size, thereby providing no support to the preference prediction. Galled leaves were significantly more asymmetric than ungalled leaves. Moreover, leaf asymmetry increased with both gall occurrence and gall size, indicating that galls boosted the stress levels in Ouratea polygyna.