Abstract Almost all reduviids are predators; however, recent observations have shown that certain reduviids, particularly members of tribe Harpactorini (Harpactorinae) may be associated with specific plants as a strategy of predation and complementary nectarivory. These observations on the occurrence of the use of nectar as food source by various species of Reduviidae, mostly Harpactorini, in Argentina (Misiones), are recorded here. Additional records of oviposition and preying by Harpactorini and Bactrodinae species on certain plants are also provided.