Uncovering the Brazilian Orthocentrinae (Hymenoptera: Ichneumonidae) fauna: high diversity at high elevation

Abstract

The Orthocentrinae is one of the least-studied groups within Ichneumonidae and possibly a major component of the tropical fauna, encompassing a rich but still obscure diversity. In this first attempt to uncover these biota in Brazil, we surveyed a restricted area within mountain chains in the southeastern region immersed in the Atlantic tropical forest, using several sampling methods along an elevational gradient. Using integrative taxonomy, we found a richness eight times higher than the current number of species known in Brazil, including 13 genera, of which 10 are new to the country. The 127 molecular taxonomic units found represent an increase of at least 50% in species for the Neotropical fauna, confirming the immense gap in taxonomic knowledge of this group in the Neotropics. Analyses of elevational gradient patterns of distribution indicated an increase in species elevational ranges with increasing elevation, supporting Rapoport’s rule. A key including all 14 genera occurring in Brazil is proposed, aiming to facilitate future taxonomic reviews and encourage research on this group. Orthocentrinae is a major component of the fauna and likely to be more diverse in wet lowland tropical forests; however, taxonomic and faunistic studies in tropical areas, including dry forests and savannahs, are needed.