Published online by Cambridge University Press: 11 July 2019
Addressing what affects predation among caterpillars, we conducted an experiment in a Bornean rain forest on 212 clay models of Tortricidae caterpillars (the herbivore) and 53 trees of Kopsia pauciflora (the host), located either in the open or under closed canopies. We predicted that the frequency of predatory attacks towards caterpillars increases (1) in canopy gaps and (2) on leaves damaged by herbivory, but (3) decreases among caterpillars that wrap their body in leaves. Each plant with caterpillar models was consecutively allocated to one of four treatments: caterpillars artificially rolled in leaves vs caterpillars on unrolled leaves, and caterpillars on artificially damaged vs undamaged leaves. Each time, caterpillar models were placed on the plants for 48 h, and then replaced with new models that were subjected to a new treatment. On average, our caterpillar models had a 21% chance of being attacked per 24 h. More attacks were performed by insects (81.6%) than birds. The attack frequency did not depend on the canopy cover or on leaf damage, but decreased among models rolled in leaves. This pattern was mainly attributable to insect attacks, which were also more frequent than bird attacks. Overall, the Tortricidae caterpillars seem to suffer comparable predation rates in the open and under closed canopies irrespective of the herbivory damage of leaves, but their leaf-rolling behaviour might reduce predation.