ARS | Publication request: Niche engineering reveals complementary resource use

Submitted to: Ecological Society of America (ESA)
Publication Type: Abstract Only
Publication Acceptance Date: April 19, 2012
Publication Date: August 9, 2012
Citation: Gable, J., Crowder, D., Northfield, T., Steffan, S.A., Snyder, W. 2012. Niche engineering reveals complementary resource use [abstract]. Ecological Society of America (ESA). Paper No. COS166.

Technical Abstract: Greater resource use by diverse communities might result from species occupying different, complementary niches. Niche partitioning is difficult to directly demonstrate, however, because differences among species in the resources they use are often difficult to separate from other species-specific traits (e.g., size, feeding rate, phylogeny). Here, we overcame this difficulty by exploiting plastic foraging behavior in a community of predatory insects. These predators complemented one another by partitioning foraging space on leaves, with some species foraging primarily along leaf edges and others at leaf centers. On intact leaves, edge- and center-foraging predators combined to kill more prey than any single predator species could on its own. These emergent diversity effects, however, disappeared on plants damaged by the caterpillar Plutella xylostella. Caterpillar chew-holes brought edge micro-habitats to the center of leaves, such that all predator species could attack aphids anywhere on the plant. With niche differences diminished, there were no benefits of predator diversity, as the most voracious single predator species killed the most aphids. Thus, caterpillar herbivory determined whether the combined impacts of multiple predator species reflected complementarity or species’ individual effects. Our study provides direct evidence for a causative relationship between niche differences and increased resource consumption by diverse communities. Ecological engineers revealed this relationship by homogenizing the foraging environment and lessening niche separation among consumers.