This is the plant x herbivore data matrix for 38 woody plant species from a lowland rainforest in Papua New Guinea and their folivorous insect herbivores. The herbivores were sampled from 1,500 m2 of foliage area for each plant species. The matrix includes the number of individuals of each herbivore species on each plant species, except for singleton records (i.e., combinations of a particular herbivore species feeding on a particular plant species supported by only a single individual) which were excluded. All records in the matrix are feeding records, verified either by rearing of larvae or no-choice feeding experiments for adults. Each herbivore species is denoted by a species code, identified as far as possible, and assigned to its feeding guild. The number of individuals (ni.) and the number of host plant species (pi) are reported for each species. These are original data obtained by research in the field. This data set is associated with the paper Insects on Plants: Explaining the Paradox of Low Diversity within Specialist Herbivore Guilds by V. Novotny, S. E. Miller, J. Hrcek, L. Baje, Y. Basset, O. T. Lewis, A. J. A. Stewart and G. D. Weiblen published in the American Naturalist. This paper includes the definition of each herbivore guild, phylogeny of the plant species, and the information on the depositories of the plant and insect vouchers documenting the data
