Polinização por abelhas generalistas melhoram o sucesso reprodutivo de Mimosa paludosa Benth. (Leguminosae) em área urbana: sistema sexual, reprodução e polinização em Mimosa

Abstract

Mimosa is the second largest genus of Leguminosae (540 spp.) and, despite this, studies on pollination ecology and sexual/reproductive system are scarce for the genus. Therefore, here we investigate some aspects of the reproductive biology of the “urban” population of M. paludosa in order to answer: (i) which sexual system does the studied population have? (ii) what morphological and functional attributes do the pollination units of M. paludosa present? (iii) is M. paludosa population pollinator-dependent? (iv) Who visits and pollinates the flowers? The population studied has “strongly” andromonoecy and flowers are pinkish, brush-like, polliniferous, diurnal, opening at dawn (before 5:30 am) and lasting 10-12 hours. Perfect and staminate flowers do not differ in terms of floral phenotype, except for the rudimentary gynoecium in the staminates and greater pollen viability in the perfect ones in relation to the staminates ((96.3% and 93.8%, respectively). We recorded self-compatibility and autonomous self-pollination (i.e. independence from pollinators) in the population, favorable characteristics in anthropized environments where there may be a pollinator scarcity. The generalist and social bees Apis mellifera and Trigona spinipes were the only floral visitors and pollinators of M. paludosa during the study, with greater reproductive efficiency of T. spinipes in fruit production (0.5) than that of A. mellifera (0.36), with the opposite occurring in seed production (0.23 and 0.63, respectively). Thus, both bee species promote an increase in the production of fruits and seeds of M. paludosa, favoring the reproductive success of the species in the study environment subject to disturbances