Mirmecofauna (Hymenoptera; Formicidae) da serapilheira de um cacaual inundável do agrossistema do Rio Mucuri, Bahia: considerações sobre conservação da fauna e controle biológico de pragas

uploaded by Plazi The ant fauna (Hymenoptera; Formicidae) of the litter of an inundating cocoa plantation along the Mucuri River, Bahia: considerations on fauna conservation and biological control of pests. In the Mucuri region, Bahia, Brazil, in the Mata Atlântica dominion, the primary forest has almost disappeared and has been substituted by pastures and mostly, eucalyptus monoculture. In this region, the cocoa is planted along the Mucuri River, in areas occupied before by gallery forests. The cocoa plantations have been established in the region according the cabruca system, on extremely fertile quaternary alluvial soils, that suffer irregular inundations. Furthermore, they are in a relative isolation from forest remnants and other cocoa producer regions of southern Bahia and Espírito Santo. The objective of this research is an evaluation of the leaf-litter ants in the Mucuri agrosystem, following criteria of fauna conservation and potential occurrence of biological control agents. It has been observed that the fauna is poorer when compared to more extensive areas of cocoa-cabruca, closer from forest remnants. Although that, it still maintain species of conservationist interest. From the point of view of biological control agents, it has been observed the absence of important predatory ants, normally present in other regions. These observations are due to three main factors: a) effect of irregular inundations that eliminate an important fraction of the soil fauna; b) occurrence of a superficial phreatic nape that does not allow the nesting of a range of terricolous species; and c) isolation from areas, possible sources of species recolonisation, in case of local extinction. It is concluded that the cabrucas in inundated soils and isolated situation have a limited interest for the conservation of hypogeaic and epigeaic arthropod fauna, but that its value for conservation of other fauna segments deserves a careful evaluation. Regarding the biological control aspects, the absence of important predatory species may allow a larger incidence of phytophagous insects