The diversity of ants (Hymenoptera: Formicidae) interacting with the invasive hibiscus mealybug <italic>Maconellicoccus hirsutus</italic> (Green 1908) (Hemiptera: Pseudococcidae) on ornamental and cultivated plants in Bahia, Brazil.

Biological invasions by exotic species are among the major threats to biodiversity worldwide. The pink hibiscus mealybug (PHM) <italic>Maconellicoccus hirsutus</italic> (Green <xref>1908</xref>) (Hemiptera: Pseudococcidae) is an invasive mealybug species that has been reported in Brazil since 2010. This species is sometimes found in mutualistic association with ants, which help spread this pest and also prey on or remove its natural enemies. Here, we describe for the first time the interactions between ants and <italic>M. hirsutus</italic> in Brazil, focusing on cocoa trees, <italic>Theobroma cacao</italic> (L., Malvaceae), and on the ornamental species <italic>Mimosa caesalpiniifolia</italic> Benth (Mimosaceae), and hibiscus <italic>Hibiscus rosa</italic>-<italic>sinensis</italic> L. (Malvaceae), all in the state of Bahia, Brazil. We collected <italic>M. hirsutus</italic> and associated ants on 50 randomly selected plants of these three species at three sites. We found a high diversity of ants (46 species) in trophobiotic interaction with the exotic mealybug. The highest ant species richness was found on hibiscus, with 33 species recorded interacting with the mealybug. Thirty ant species were observed associated with <italic>M. hirsutus</italic> on cocoa trees. We found significant differences in the ant assemblages according to site and plant species. Mutualisms with exotic species can cause profound alterations in the communities where they are inserted. This description of ant—<italic>M. hirsutus</italic> associations in Brazil is an initial step towards a better understanding of the mechanisms by which these mutual interactions become structured in the Neotropics and of their impacts on environment and agriculture. [ABSTRACT FROM AUTHOR]