Potencial de Formigas (Hymenoptera: Formicidae) como Agentes Anti-herbívoros em Cultivo de Café (Coffea canephora Pierre) e Feijão Guandu [Cajanus cajans (L.) Millsp]

Este trabalho analisou a variacao no potencial das formigas como agentes anti-herbivoros em plantas de cafe ( Coffea canephora Pierre) e guandu [ Cajanus cajans (L.) Millsp]. Foram usados ovos artificiais, simulando a presenca de insetos herbivoros, e solucao de acucar, para aumentar a atividade de formigas, em experimentos de campo. As plantas de cafe e de guandu possuiam diferentes niveis de atividade de formigas, pois as ultimas eram atacadas por membracideos que atraiam mais formigas. A atividade das formigas foi monitorada apos aplicacao de solucao de acucar e a remocao de ovos artificiais foi medida apos 24 e 48 horas. A solucao de acucar aumentou significativamente a atividade de formigas em plantas de cafe e de guandu. A remocao dos ovos artificiais foi significativamente maior em ramos com formigas do que sem formigas para as plantas de guandu. A adicao de solucao de acucar aumentou a remocao de ovos artificiais em plantas de guandu, mas nao em plantas de cafe. O tratamento com solucao de acucar e a presenca de membracideos em guandu tiveram efeitos similares sobre a atividade de formigas. Este estudo mostrou que a aplicacao de solucao de acucar pode ser utilizada para simular a presenca de membracideos sobre as plantas, aumentando a atividade de formigas. Isso permitiu a avaliacao de seu potencial como agentes anti-herbivoros, atraves de experimentos que simulam a presenca de insetos sobre as plantas. Potential of Ants (Hymenoptera: Formicidae) as Anti-herbivore Agents in Cultivation of the Coffee ( Coffea canephora Pierre) and Pigeon Pea [ Cajanus cajans (L.) Millsp] Abstract. This study analyzed the role of ants as anti-herbivore agents in Coffee ( Coffea canephora Pierre) and Pigeon Pea [ Cajanus cajans (L.) Millsp] plants in agroecosystem under organic management. In these plants we used artificial eggs and sugar solution in experiments that simulated the presence of herbivore insects. Coffee plants did not possess any natural attractive that could intensify foraging activity of ants, but pigeon pea plants were infested by treehoppers which attracted ants. Activity of ants was surveyed after sugar solution application and artificial eggs removal was measured 24 and 48 h after start of the experiments. Sugar solution sprinkled on plants foliage increased significantly the activity of ants on coffee and pigeon pea plants. The removal of artificial eggs was significantly greater in branch with ants than without ants for pigeon pea plants. The sugar solution addiction resulted in greater artificial eggs removal in pigeon pea plants, but not in coffee plants. The treatment with sugar solution and presence of treehoppers had similar effects on the activity of ants on the plants. This study showed that the application of sugar solution can be used to increase activity of ants on plants as well as the potential of ants as anti-herbivore agents can be evaluated in experiments that simulate the presence of insects on the plants.