Ecologia das comunidades de formigas associadas a plantas da família Arecaceae da ilha do Combu (Belém) e Estação Científica Ferreira Penna, em Caxiuanã (Melgaço-PA)

Abstract

The Amazon is the main center of Neotropical palm diversity (Küchmeister et al., 1998). This family presents special morphological and physiological adaptations regarding the interrelations of its structures with its colonizers and visitors. Ants specialized to live in myrmecophytes take advantage of plant structures as nesting sites and also show morphological and behavioral adaptations (Harada, 1989). The gradual deposition of organic material on the bracts of palm communities stimulates the habitation of these spaces by ant communities producing an intrinsic relationship between these communities. This project aimed to study the association patterns and interactions between ants and plants of the Arecaceae family and their spatial-temporal distribution on the island of Combu (IC) (Belém) and Scientific Station Ferreira Penna (ECFPn), in Caxiuanã (Melgaço/PA). At each collection site six points were chosen for data sampling. At each point, data and material were collected from five plants colonized by ants, within a maximum radius of 15 m apart. At each plant the ant colonies present, data on the plant, and a description of the environment were collected. To analyze the percentage of nesting ants in the palm trees, 20 plants were counted within a 50 x 50 m transect at each point, observing the presence or absence of ants. Bio Estat 2.0, Bio Diversity Pro and Estimates 5.0 were used for data analysis. A total of 30,907 ants were collected from 60 palm trees over two sampling periods. The ant communities were distributed among 15 genera and 39 species, collected from 15 palm species. Of this total, 18,819 ants were collected in the ECFPn and 12,088 in the CI. Of these ant species 15 were unique to ECFPn, 17 to CI and 7 common to both sampling sites. Of the 240 palms sampled for nesting percentage analysis, 103 showed nesting ant colonies, with a colonization percentage of 42.92%. In theECFPn29.16% of palms had their bracts colonized by one or more ant species, however, in the CI a total of 56.67% palms inhabited by ants were observed. The diversity by sampling site did not have significant differences, according to Shannon and Simpson indices. Inajá (Attalea maripa Mart.) was the palm tree with the highest ant species richness (09 sp) in the ECFPn, followed by Açaí (Euterpe oleracea Mart.) (08) in the IC. The seasonality and influence the abundance of the ant communities, since in periods of higher rainfall, this abundance is higher (34.782), when compared to periods of greater drought (30.907). The moisture in the bracts favors the proliferation of more species in these spaces. According to data and observations it is possible to infer that there is an intrinsic relationship between palm and ant communities, however, the presence of ants in palm trees is greater in flooded environments (várzeas, p. x. IC), a fact that corroborates the ease of morphological and behavioral adaptation of ants. The mutualistic relationship between the two communities is very clear and the evidence of specificity between some species of ants and palm trees is quite evident.