MANEJO DE SEMENTES POR Dinoponera gigantea (HYMENOPTERA: FORMICIDAE) EM UMA ÁREA DE CERRADO NO NORDESTE DO BRASIL

Abstract

The handling of fruits and seeds by ants involves a series of stages that range from collection, manipulation, and use to the final destination of these resources. The study of interactions between Dinoponera gigantea and seeds helps in understanding the ecological functions performed by this species in the Cerrado environment. This work evaluated the process of collection, transport, and fate of the seeds used by D. gigantea, as well as the influence of this interaction on seed germination in a Cerrado area in Northeastern Brazil. To investigate collection and dispersal, diaspores of Davilla nitida and Palicourea hoffmannseggiana, with and without elaiosomes, were offered at 10 sampling stations located around nests and foraging trails. To assess the effect of seed manipulation on germination, three treatments were conducted under controlled conditions (270 seeds): seeds collected from nests without elaiosomes (I), seeds preserved from the mother plant (II), and seeds with manually removed elaiosomes (III). Higher collection and dispersal rates were recorded for P. hoffmannseggiana: 54% of collected seeds were dispersed, while 46% were taken into the nests, with distances ranging between 3 and 25 meters. Seeds with elaiosomes and an average size of 0.6 cm were the most collected. Collection was influenced by the number of ants, seed size, and the presence of elaiosomes, but not by distance, temperature, or humidity. Excavated nests had an average depth of 35 cm, 8 internal chambers, and between 30 and 44 ants per nest; seeds were mostly found in the third chamber, all without elaiosomes. Germination tests showed that 73.7% of the seeds germinated, with no significant statistical differences among treatments. Treatment III, however, showed a higher germination percentage (81.1%), a higher germination speed index (3.0), and a lower mean germination time (34.7 days), indicating greater efficiency. The presence or absence of elaiosomes did not significantly affect the germination process, while the action of D. gigantea did not exert direct interference. These results enhance the understanding of interactions between fauna and flora, highlight the ecological role of D. gigantea in dispersal dynamics, and reinforce the importance of conserving this key species in Cerrado ecosystems.