Spatial Variation in Ant Species Occupancy

 To assess within-tree habitat partitioning, Tillberg (2003) classified domatia

according to their relative vertical position on the plant for 2-yr-old trees (i.e., low-, mid-

and high-level branches) and I classified domatia according to their relative age for the 5-

yr-old trees (i.e., younger domatia from terminal and subterminal branches vs. older

domatia from large branches and the bole). The domatia from higher branches of 2-yr-

old plants were similar in age and physical condition to the domatia from the terminal or

subterminal branches of the 5-yr-old plants, making these categories somewhat

comparable. Because the 1-yr-old plants did not have sufficient numbers of domatia or

the branching structure required to make such classifications, they were excluded from

the analysis.

 I used chi-square tests to examine the frequency of species occurrence in domatia

from different parts of the trees, with expected values for the test of within-tree habitat

partitioning derived from the total proportion of domatia occupied by each species. To

examine relationships among the occupation patterns of the three most abundant species I

performed ANOVA on the proportion of domatia they occupied in 2- and 5-yr-old trees.

Colony Founding and Expansion

 Although there were other mature C. alliodora individuals surrounding the

Huertos Project, I assumed that the dozens of 5-yr-old plants in the immediately adjacent

planting were the most likely source population from which foundress queens would

colonize the 1-yr-old plants. Therefore, I used chi-square tests to analyze the ant

occupation of 1-yr-old trees, with the expected values for frequency of ant occupation

derived from the proportion of domatia occupied by each species on the 5-yr-old trees.

These proportions were pooled across the three blocks.