Guild‐specific patterns of species richness and host specialization in plant–herbivore food webs from a tropical forest

Abstract

Summary 1.The extent to which plant-herbivore feeding interactions are specialized is key to understand the processes maintaining the diversity of both tropical forest plants and their insect herbivores. However, studies documenting the full complexity of tropical plant-herbivore food webs are lacking. 2. We describe a complex, species-rich plant-herbivore food web for lowland rain forest in Papua New Guinea, resolving 6818 feeding links between 224 plant species and 1490 herbivore species drawn from 11 distinct feeding guilds. By standardizing sampling intensity and the phylogenetic diversity of focal plants, we are able to make the first rigorous and unbiased comparisons of specificity patterns across feeding guilds. 3. Specificity was highly variable among guilds, spanning almost the full range of theoretically possible values from extreme trophic generalization to monophagy. 4. We identify guilds of herbivores that are most likely to influence the composition of tropical forest vegetation through density-dependent herbivory or apparent competition. 5. We calculate that 251 herbivore species (48 of them unique) are associated with each rain forest tree species in our study site so that the 200 tree species coexisting in the lowland rain forest community are involved in 50 000 trophic interactions with 9600 herbivore species of insects. This is the first estimate of total herbivore and interaction number in a rain forest plant-herbivore food web. 6. A comprehensive classification of insect herbivores into 24 guilds is proposed, providing a framework for comparative analyses across ecosystems and geographical regions.

Parasitism rate, parasitoid community composition and host specificity on exposed and semi-concealed caterpillars from a tropical rainforest

“…It is even more difficult to fully describe the host range of a parasitoid compared to describing the parasitoid complex of a host, because for the former a broad sampling of potential host species is necessary (Shaw 1994;Whitfield and Wagner 1988). In a rainforest food web, there may be an order of magnitude higher number of potential host species for parasitoids than potential host plant species for herbivores (Novotny et al 2010). Unsurprisingly, herbivore host specificity is better known than that of parasitoids in tropical food webs.…”

Habitat structure and host plant specialization drive taxonomic andfunctional composition of Heteroptera in postfire successional habitats

“…This conclusion opens future research to examine the role of plant-bug interactions in postfire ecological trajectories. Plant-herbivore feeding interactions are key phenomena for understanding processes that maintain biodiversity (Novotny et al, 2010). These interactions make up antagonistic networks characterized by cohesive groups of interacting species (Bascompte and Jordano, 2006) and promote compartmentalization through coevolution of specific defenses and counter-defenses that generate greater specificity (Thompson, 2005).…”

DNA Barcodes of Lepidoptera Reared from Yawan, Papua New Guinea

“…Methods for handling the Lepidoptera are described by Miller (2015), Miller et al (2003), and Novotny et al (2010). DNA sequencing (COI barcode) followed standard methods at the Biodiversity Institute of Ontario, University of Guelph , Wilson 2012, using legs and the LepF1 and LepR1 primers.…”