Tending-Ants Increase Survivorship and Reproductive Success of Calloconophora pugionata Drietch (Hemiptera, Membracidae), a Trophobiont Herbivore of Myrcia obovata O.Berg (Myrtales, Myrtaceae)

Roberth Fagundes, Sérvio Pontes Ribeiro, Kleber Del Claro

The trophic relations between ants and hemipterans are very common in the Neotropical Region, but rarely explored in montane ecosystems. Given that the diversity of outcomes of these type of interactions are influenced by variation in biotic conditions (i.e. seasonality, spatial distribution, identity of species involved), new examples in different ecosystems can provide important data for a general understanding of their impact on the community. We investigated the outcomes (direct benefits: survivorship and reproduction) of the relationship between the trophobiont herbivore Calloconophora pugionata (Membracidae) and its tending ants. The interaction occurs on Myrcia obovata (Myrtaceae), a common tree in montane forests and rupestrian fields of southeastern Brazil, and has never been studied before. Between 2008 and 2009, we selected and manipulated (ant-exclusion) trees in a pairwise experiment performed on branches infested by C. pugionata. This Membracidae has a peculiar way of laying eggs on the leaf margins, a behaviour that increased egg survival even when ants were absent. All life stages of the hemipteran exhibited higher survival rates (two-fold) and increased fecundity (four-fold higher oviposition rates) when attended by ants. This study shows that this ant-hemipteran interaction behaves in montane biomes similarly to other tropical ecosystems with ants protecting the hemipterans against predators and increasing their survival and reproductive fitness.