How plants and honeydew-producing hemipteran insects affect ant species richness and structure in a tropical forest zone

Extrafloral nectaries (EFNs) and hemipteran honeydew are often discussed as two alternative mechanisms encouraging ant visitation in mutualistic ant–plant relationships, but little is known about the processes that generate distribution pattern in species-rich insect communities. A case study on the interaction between ants, EFN-bearing plants and hemipterans was investigated along a gradient of increasing disturbance from regenerated forest to mixed crop field. Ants, EFN-bearing plants and hemipterans sampling was conducted in these vegetations during the wet and the dry seasons in five locations. Results showed that partitioning of ant species between season and vegetation was significantly different from random. High specialization index was observed in hemipterans/plants and ant/hemipterans interactions. Low specialization index was observed between ants and EFN-bearing plants mainly in the mixed crop field. Ant species were mostly found in non-aggressive co-occurrence at nectar sources. At the species level, specialization index was high for Anoplolepis tenella (0.86 ± 0.06) and also for its associated hemipterans Stictococcus vayssierei (0.97 ± 0.02). This association is detrimental to food crop especially cassava. These results outline the effect of vegetation and food source on the structure of the ant assemblage and interaction in tropical forest zone.