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In a fragmented Brazilian landscape, 24 species of ant, which are considered to be open-area specialists, occur exclusively in the pasture areas around the forest remnant (matrix). In this paper, we propose possible theoretical explanations for the occurrence of these exclusively matrix species, and suggest that these species originally occurred in forest gaps. We also determine whether these species occur in another type of open vegetation, the cerrado (Brazilian savanna). Ants were collected from ten forest gaps within three forest remnants. Ant species sampled in forest gaps were compared to ant species collected from the cerrado. The aim here was to determine whether there were any similarities between the two sets of species, and also to collect information about the origin of matrix ant species. In the forest gaps, we sampled 44 species of ant. Of these, 11 species were also found to occur in matrix areasand eight species in the cerrado vegetation. Two scenarios could explain this result: (I) exotic ant species of open biomes migrate to, and establish in, the matrix; or (II) the species that currently occur exclusively in the matrix areas are originally from forest gaps and have increased their distribution following the fragmentation event. We discuss reasons to support these scenarios as wellas their implications for other ecological and conservation processes.

We evaluated the relation of cricket species richness and composition with forest regeneration time, evaluating canopy and litter depth as environmental drivers. Effects of forest patch area, nearest distance to the 300-year patch, cricket abundance, sampling sufficiency, and nestedness were also evaluated. We collected 1174 individuals (five families, 19 species). Species richness increased asymptotically with regeneration time and linearly with canopy cover and litter depth. Canopy cover increased linearly, while litter depth increased asymptotically. Richness was not affected by patch area and nearest distance to the 300-year patch. Richness increased with cricket abundance, and this explanation could not be distinguished from regeneration time, evidencing collinearity of these two explanatory variables. Rarefaction curve slopes increased with regeneration time. Species composition differed among patches, with no nested pattern. We suggest that regeneration and consequent increases in canopy and litter promote recovery of cricket biodiversity, abundance, and changes in species composition. We conclude that the recovery of cricket diversity involves an increase along the spatial scale of complementarity, together with a change in species composition.

In a tropical forest patch of Southeastern Brazil, adult Scarabaeidae beetles were used to test the hypothesis that fungivorous guilds have a higher proportion of generalist species than either frugivorous, necrophagous or coprophagous ones. No significant differences were found between guilds in relation to either the proportion of generalists or niche breadths of the component species. Only two fungivorous specialist species were sampled. These results indicate that sporocarps eaten by Scarabaeidae are not as rare as literature suggests. Fungi may help maintain high species diversity of Scarabaeidae in tropical forests.