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.
