Multiple Predator Interactions and Food-Web Connectance: Implications for Biological Control

摘要: The use of single versus multiple natural enemies in biological control remains controversial, largely due to the possibility for antagonistic interactions among predators (e.g., intraguild predation and cannibalism) that can reduce potential top-down pest herbivores. Using a system, Spartina cordgrass its associated community arthropods (herbivores, strict predators), we created 29 different treatment combinations varied richness (number predator species) trophic composition (proportion predators) measured ability each density key herbivore (the planthopper Prokelisia dolus) system. We then calculated food-web connectance fraction all possible directed feeding links are realized food web) experimental webs. Notably, is enhanced by predator-predator such as cannibalism. found significant negative relationship between complex prey populations. Specifically, well-connected webs comprised mostly species were far less effective at suppressing herbivores than consisting predators. Importantly, web was more influential affecting control. also discovered when structural complexity habitat increased, result attributable spatial refuges relaxed predation. Thus, this structure has transform into less-connected one reducing resulting from Because remarkable similarity system tropical Asian rice, finding provides encouragement effectiveness be management practices increase thereby dampen Last, discuss how analyses might used evaluate particular