Leaf miners on Ochna ciliata (Ochnaceae) growing on Aldabra Atoll: patterns of herbivory in relation to goat browsing and exposure to the sun

Abstract.

• 1 The patterns of herbivory by leaf miners on the shrub Ochna ciliata growing on Aldabra Atoll were studied in relation to browsing by feral goats and exposure to the tropical sun versus shading.
• 2 Damage due to both tunnelling (Diptera) and ‘blotch-making’ (Lepidoptera) leaf miners was statistically greater on trees that had been browsed and on those that received more extensive exposure to the sun.
• 3 Effects of exposure and browsing were additive, as evidenced by the lack of statistical interaction between these factors.
• 4 There was a significant negative correlation between the numbers of tunnelling and blotch-making miners in trees that had been browsed, but not in unbrowsed trees.
• 5 Three geographical areas were sampled to test whether the effects of browsing on leaf mining were invariant or influenced by as yet unknown environmental factors. A statistically significant interaction between browsing and geographical region indicated that, while browsed trees had significantly more mines whatever the habitat, the extent of this effect differed across the habitats.