A comunidade de Braconidae (Hymenoptera; Ichneumonoidea) em um gradiente altitudinal no Parque Nacional do Itatiaia, RJ: taxonomia, distribuição e diversidade

Abstract

In Brazil, there are few studies on mountain ecosystems that aims the biodiversity conservation, even with hymenoptera parasitoids, especially the family Braconidae, a group ecologically important, because they represent the diversity of other groups of insects, that are their hosts. This study aimed to contribute to the knowledge of the diversity of Braconidae fauna into a mountain ecosystem at Parque Nacional do Itatiaia, Rio de Janeiro, Brazil. The sampling were made with Malaise traps (TOWNES, 1972) installed between 987 and 2255 meters, in two mountain slopes (continental and coastal), comprising three vegetation types of the Atlantic Forest existent in the study area (Montane and High Montane Ombrophilous Dense Forest and Campos de Altitude). Four altitudes were sampled for 10 months of sampling between 2011 and 2012 and seven altitudes in 14 months were sampled between 2013 and 2014. In total 9.854 individuals of Braconidae were captured, in which, 8.814 individuals were identified and distributed in 28 subfamilies and 125 genera. The most abundant subfamilies were Alysiinae Microgastrinae, Doryctinae, Braconinae e Opiinae. The most abundant genera were Opius, Heterospilus, e Bracon. The rainy season promoted the major richness and abundance of subfamilies and genera. Two patterns of the richness and abundance distribution were observed: in the gradient sampled in 2011-2012, the richness and abundance increased with altitude showing peak in the highest altitude; in the gradient sampled in 2013-2014 was observed a peak on intermediate altitude, followed by decline with elevation. The richness accumulation curves have not reached the asymptotic stage. However, the richness estimators showed that the sampling period was sufficient to know most of the local fauna. Most of the abundant genera showed high amplitude of altitudinal distribution. It was observed a great number of exclusive genera. Some of the main subfamilies showed preference for higher altitudes. Most of the identified fauna are cenobiont, endoparasitoid solitary of larval stage of Lepidoptera, with small range of hosts. Many identified genera have biological information missing. Apparently the parasitoids community structure was strongly influenced by the vegetation gradient on mountain. The High montane vegetation showed a richer fauna, and the Campos de altitude, showed a more dominant fauna. In the gradient sampled in 2011-2012, cenobionts and idiobionts showed peaks in the highest altitudes, in the gradient sampled in 2013-2014, cenobionts and idiobionts showed a peak in distinct altitudes. In the spatial and temporal distribution of cenobionts and idiobionts, it was observed a typical pattern of competition. In the highest altitudes, ectoparasitoids were more frequent than endoparasitoids. Most of the genera without species recorded for Neotropical Region and Brazil, were more frequent in the highest altitudes. Two genera new for science were recognized, and at least 46 new species were discovered. Studies such as this show the importance of research in altitude ecosystems, allowing the biodiversity and the ecological importance of these habitats to be known.