experienced more proportional leaf damage than the 5-yr-old plants and that fertilization

reduced herbivory for the younger plants (Fig. 3-4). When the two ages were analyzed

separately, fertilization did not significantly affect the proportion of leaf area missing for

either, but the number of ants had a significant negative effect on herbivory for the 5-yr-

old plants (Table 3-5).

Leaf Palatability Bioassay

 The results of the ANOVA for the leaf palatability trial showed that fertilization

significantly affected the amount of leaf area consumed by C. leprosa, whereas leaf age

had only a marginally significant effect and there was no effect of plant age (Table 3-6).

Overall, the beetles consumed more material from young leaves than from mature leaves,

and more from the leaves of unfertilized plants than from fertilized plants. However,

these main effects were mainly due to the high leaf area consumed from young,

unfertilized leaves, as indicated by the marginally significant interaction effect between

fertilization treatment and leaf age (Fig. 3-6). None of the other interactions among

factors were statistically significant.

 Discussion

 The relationships between different types of plant defenses are often complex and

may vary over the ontogeny of the plant and according to resource availability and the

efficacy of ant defense (Folgarait and Davidson 1994, 1995, Nomura et al. 2001, Del Val

and Dirzo 2003, Dyer et al. 2004). In this study, I investigated the patterns of herbivory

on Cordia alliodora, a common myrmecophytic tree, in relation to plant age, fertilization

and ant abundance. Identifying variation in the benefits and costs associated with

different partners in mutualist guilds and determining the consequences of such variation

are major objectives of holistic examination of mutualism (Stanton 2003). The presence