To determine the resources utilized, three species of solitary bees of Jalisco, Mexico, were investigated by microscopic pollen analysis of nest cell contents and pollen loads of females. By this measure, Centris analis Fabricius and C. trigonoides Lepeletier were polylectic without strong preference for a single plant family, visiting flowers of Flaccourtiaceae, Leguminosae, Malpighiaceae and Solanaceae, mainly. C. nitida F. Smith was also polylectic
its most important sources are Malpighiaceae, Myrtaceae and Solanaceae, sometimes with a strong preference for the Malpighiaceae (88%). These species visit a wide spectrum of flowers, C analis 23 species, C nitida 46 and C trigonoides 16, but only a few species were of importance (greater than or equal to10%). C nitida visited more plant species to obtain resources and displayed a homogeneous foraging behavior. C. analis and C. trigonoides forage fewer resources and these were exploited in a heterogeneous way. Samples of the three species showed lower values of similarity in terms of the sources visited.
