Community structure of ants (Hymenoptera: Formicidae) in a series of habitats associated with citrus.
A transect of forty-four pitfall traps passing through eleven point habitats associated with citrus in South Africa captured 10 488 individuals comprising twenty-three genera and forty-nine species. Rank-abundance plots showed increasing equitability within habitats ranging from young orchard through old orchard and rank grassland to sparse grassland. The dominant species accounted for as much as 95.7% of individuals in the young orchard and as little as 17.6% in sparse grassland. Overall, Pheidole was the dominant genus. In all but one habitat, one or other Pheidole species dominated. In grassland, but not so much in the orchards, there was a two-dimensional mosaic distribution of ants. At the nominal level, most habitats shared the majority of species. However, at the ordinal level the rank sequence of ants varied considerably from one habitat to another. On the basis of ant abundance at the interval level, habitats grouped according to overall physiognomy, and could be arranged in the following general sequence: old orchard, young orchard, rank grassland, sparse grassland. This illustrated that all but the most abundant species were habitat-sensitive. Further, there was a positive correlation between the number of habitats in which an ant occurred and its overall abundance. This suggested that habitat modification would be unsuitable as a primary method of ant management. Instead, trunk banding, which cuts off the ants' nests from the honeydew source in the tree, is an ecologically more appropriate method of management.