O EFEITO DE BORDA SOBRE A COMUNIDADE DE HYMENOPTERA QUE NIDIFICA EM CAVIDADES PREEXISTENTES E SEUS PARASITOIDES ASSOCIADOS

Abstract

One of the main global concerns is related to the loss of biodiversity, since the fragmentation of forests has been occurring on a large scale due to human population growth. Due to environmental changes, the abundance and richness of many species of living beings are altered, putting at risk of extinction many of the species that are sensitive to changes in their habitats. With the loss of forests, edges are becoming more abundant and depending on the fragmentation composition, areas may be suffering edge influence. The objective of this study was to identify how the Hymenoptera community that nests in preexisting cavities and its natural enemies respond to the edge effect, in matrix and forest fragment areas. We explore the following hypotheses: (I) The response of the Hymenoptera community that nests in preexisting cavities in relation to the edge is neutral (H0: Model without response); (II) the more generalist species will respond positively to edge effects (H1: edge preference model); (III) species that have a greater preference for open areas are more abundant in the anthropogenic matrix (H2: Model of species that avoid forests) and (IV) species that specialize in forest areas have a greater preference for the interior of forest fragments (H3: Model preferably forest). Data were collected in four areas of Atlantic Forest fragment and in four areas of adjacent matrix, in Guarapuava, (PR), Brazil, from August 2018 to August 2019. For the sampling of these insects, 1,536 trap nests were installed, made with wood and bamboo. A total of 541 nests were founded, from which 1,420 hosts and 254 natural enemies emerged, among the hosts 25 were bees belonging to four species and 1,395 were wasps belonging to 16 species. Of the 254 natural enemies, 21 species belonged to the order Hymenoptera and three species belonged to the order Diptera. By means of the GAM and GAMM analyses, it was possible to observe that the species that nested in environments of matrix areas obtained positive responses to the edge effect, while the species that nested only in forest areas presented negative responses to the edge effect. We conclude that the species Trypoxylon agamemnon, Pisoxylon amenkei, Podium sp.1, Podium sp.2, Podium sp.3, Hypodynerus duckei, Zethus pilosus and Zethus plaumanni, which nest only in forest areas, are species that depend exclusively on these environments. The natural enemies Ipisiura lilloi, Photocryptus sp1, Xystromutilla bucki, Ipisiura myops, Tetrastischus sp, Messatoporus sp1, Ceyxia longispina and Photocryptus sp were found parasitizing hosts only in forested areas, being therefore also dependent on forested areas due to the preference of their hosts to nest only in forests, thus it is necessary to preserve areas of natural habitat for the conservation of these species.