Abstract By influencing the exchange of pollen, floral visitor behavior largely promotes the reproductive success of the plants. Pontederia sagittata (C. Presl) (Commelinales: Pontederiaceae) is a tristylous species whose morphs (long-styled L, mid-styled M and short-styled S) differ in the arrangement of reproductive organs and the amounts and accessibility for food for pollinating insects. We evaluated the behavior of 2 common contemporary visitors to inflorescences, the exotic bee Apis mellifera (L.) (Apidae), a not historical pollinator, and the flower fly Lycastrirhyncha nitens (Bigot) (Syrphidae), a frequent visitor already reported on this aquatic plant, based on HD video records of the number of individuals and the frequency and duration of their visits to 300 inflorescences. Both species of insects preferred to visit S-morph inflorescences. Pollen collection and nectar feeding were the most important activities of the bees, whereas flower flies were observed fed only on nectar. Thus, these behavi...