Print PageUnderstanding the extent and causes of tropical insect diversity requires both taxonomic surveys of insects at particular sites and knowing trophic (feeding) interactions between species. The trophic data builds food webs, which can provide insights on the structuring of insect communities. The inventory of the caterpillars, their food plants and parasitoids of the Area de Conservación Guanacaste (ACG) in Costa Rica provides both extensive taxonomic and trophic data. What insights into the structuring of hyperdiverse insect communities can be gained from analyzing the ACG dataset? Here, we constructed and analyzed food webs for microgastrine parasitoid wasps, the caterpillars parasitized and the host plants eaten from the ACG inventory.
Results/Conclusions
The food web included 509 species of parasitoid wasps, 735 species of caterpillars (in 26 families) and 647 plant species (in 102 plant families), which formed 1,480 unique tri-trophic interactions. Between trophic levels, connectance was low (0.0006) with just 1.17 links per species, indicating a very high degree of host specialization. Within each trophic level, most species were rare and there were relatively few very common species. We also randomized the trophic interactions, controlling by the observed abundance, to identify which interactions were more or less common than expected by chance. Most interactions occur between species of intermediate and high abundance as expected, but interactions between rare species are observed in some cases more frequently than expected. This result suggests extinction of rare hosts and parasitoids may be common and understanding of these hyperdiverse communities needs to also consider immigration from a larger metacommunity as well as rapid diversification driven by host selection.
