Plant-Insect Food Webs and Tropical Rain Forest Succession

Plants and their insect herbivores represent 40% of global terrestrial biodiversity and yet little is known of their ecology in the tropics. It is not known, for example, whether an insect picked at random from a tropical rainforest is more likely to be a generalist, feeding on numerous plant species, or a specialist that is fully dependent on a single plant species. This information is needed to predict the vulnerability of insect species to extinction resulting from the fragmentation and loss of tropical ecosystems. This study is one of the most comprehensive surveys of plant-herbivore interactions in the tropics, focusing on several ecological groups (guilds) of insect herbivores that feed on the foliage and wood of numerous tree species in the lowland rainforest of Papua New Guinea. The investigators expect to document the larval stages, host associations and parasitoids of approximately 1,000 insect species feeding on the most common tree species in young and mature rainforests. All woody plants in four hectares of forest, two of each forest type, will be inventoried, and insects will be reared from the vegetation. The investigators will test differences between forest types in host specificity and species richness to understand the assembly of plant-insect food webs after disturbance.

The broader impacts of this activity include the strengthening of international scientific collaboration, the training of a new generation of tropical biologists, and the collection of data for tropical forest management and policy making. The project involves underrepresented Pacific Islanders in scientific research through student training and citizen scientists (parataxonomists). It builds capacity for entomology and botany in New Guinea by strengthening a local research station and developing national plant and insect collection. Results can be applied to developing conservation strategies for New Guinea, one of the top three remaining tropical wilderness areas in the world.