Macaranga, a paleotropical genus of the Euphorbiaceae, includes many myrmecophytes, which provide nesting space and specialized food for ants. In turn, ants protect their host plants from herbivores or vines. Previous studies have shown that there is great variation in the intensity of ant defense when host plants are injured. However, there have been few studies on variation in the intensity of daily ant patrolling. Therefore, we counted the number of patrolling ants on eight Macaranga species to determine whether or not there was any interspecific difference.

There was great variation among species in the number of patrolling ants. Moreover, the mode of patrolling by ants could be categorized into three groups: 1) ants protected all leaves (1 species); 2) ants protected mainly the upper part of the plants (5 species); and 3) ants protected only slightly regardless of leaf position (2 species). These patterns could be explained well by considering leaf turnover rate, and ant defense was found to be most intensive on young leaves and on leaves with short longevity.