| Autor: |
Sanz-Veiga PA; Laboratório de Ecologia da Polinização e Interações-LEPI, Programa de Pós-graduação em Ciências Biológicas (Botânica), Instituto de Biociências, Universidade Estadual Paulista 'Júlio de Mesquita Filho', Botucatu, São Paulo, Brazil., Ré Jorge L; Departamento de Biologia animal, Universidade Estadual de Campinas, Campinas, São Paulo, Brazil., Benitez-Vieyra S; Instituto Multidisciplinario de Biología Vegetal (CONICET), Universidad Nacional de Córdoba, Ciudad de Córdoba, Córdoba, Argentina., Amorim FW; Laboratório de Ecologia da Polinização e Interações-LEPI, Programa de Pós-graduação em Ciências Biológicas (Botânica), Instituto de Biociências, Universidade Estadual Paulista 'Júlio de Mesquita Filho', Botucatu, São Paulo, Brazil.; Laboratório de Ecologia da Polinização e Interações-LEPI, Departamento de Botânica, Instituto de Biociências, Universidade Estadual Paulista 'Júlio de Mesquita Filho', Botucatu, São Paulo, Brazil. |
| Abstrakt: |
Extrafloral nectaries can occur in both vegetative and reproductive plant structures. In many Rubiaceae species in the Brazilian Cerrado, after corolla abscission, the floral nectary continues to secret nectar throughout fruit development originating post-floral pericarpial nectaries which commonly attract many ant species. The occurrence of such nectar secreting structures might be strategic for fruit protection against seed predators, as plants are expected to invest higher on more valuable and vulnerable parts. Here, we performed ant exclusion experiments to investigate whether the interaction with ants mediated by the pericarpial nectaries of Tocoyena formosa affects plant reproductive success by reducing the number of pre-dispersal seed predators. We also assessed whether ant protection was dependent on ant species composition and resource availability. Although most of the plants were visited by large and aggressive ant species, such as Ectatomma tuberculatum and species of the genus Camponotus, ants did not protect fruits against seed predators. Furthermore, the result of the interaction was neither related to ant species composition nor to the availability of resources. We suggest that these results may be related to the nature and behavior of the most important seed predators, like Hemicolpus abdominalis weevil which the exoskeleton toughness prevent it from being predated by most ant species. On the other hand, not explored factors, such as reward quality, local ant abundance, ant colony characteristics and/or the presence of alternative energetic sources could also account for variations in ant frequency, composition, and finally ant protective effects, highlighting the conditionality of facultative plant-ant mutualisms. |
