Résumé
Abstract Ants are known to feed on a variety of plant resources. Nevertheless, there are very few reports in the literature on ants using flower parts. Here, we describe how two Odontomachus chelifer (Latreille) ants teared and removed a part of an inner tepal of a Neomarica candida (Hassl.) (Iridaceae) flower at the restinga sandy forest in the Cardoso Island State Park, Brazil. To determine which part of the perianth attracted these ants, we performed two independent two-choice field assays: tepals (inner and outer tepals) were cut in two parts (basal and apical), with contrasting colors, which were offered to ants leaving a colony. Our results show that ants significantly preferred to remove or lick the basal part of the inner tepal. Based on the knowledge of N. candida's floral anatomy, we hypothesize that ants were attracted by the nectar produced by trichomatic nectaries at the basal part of the inner tepals. These tepal parts containing nectar are likely to be used as an alternative food resource amid the scarcity of arthropods usually preyed or scavenged by O. chelifer, since the restinga forest is known as an arthropod-poor habitat.
Résumé
Vochysia elliptica (Vochysiaceae) is a shrubby plant, which does not have EFNs. Camponotus ants thieve nectar, and can decrease plant fitness by making flowers less attractive to pollinators. However, ants remove herbivores, wich can be beneficial. Results show that plants from which ants were excluded had lower rates of termite (simulated herbivore) removal than did plants visited by ants. Plants accessible to ants showed higher rates of termite removal in the base of leaves and in the inflorescence, than in the tip of leaves. This occurs because ants must pass through the principal axis to reach the inflorescence. Conclusive results of this cost/benefit analysis of the Camponotus sp. presence for V. elliptica can be obtained, with experimental manipulations.
Vochysia elliptica (Vochysiaceae) é uma planta arbustiva que não porta NEFs. Formigas Camponotus roubam néctar e podem diminuir a aptidão da planta, tornando as flores menos atrativas para polinizadores. O efeito das formigas na remoção dos herbívoros, no entanto, pode ser benéfico. Resultados evidenciaram que plantas cujas formigas foram excluídas tiveram menor taxa de remoção de cupins (herbívoros simulados) do que plantas visitadas por formigas. Plantas com acesso às formigas apresentaram maior taxa de cupins removidos na base das folhas e na inflorescência do que na ponta das folhas. Isso ocorre porque formigas devem passar através do eixo principal para alcançar a inflorescência. Resultados conclusivos dessa análise de custo/benefício da presença de Camponotus sp. para V. elliptica deverão ser obtidos no futuro, com manipulações experimentais.