Herbivorous mites as ecological engineers: indirect effects on arthropods inhabiting papaya foliage.
We examined the potential of a leaf roller to indirectly influence a community of arthropods. Two mite species are the key herbivores on papaya leaves in Hawaii: a spider mite, Tetranychus cinnabarinus Boisduval, and an eriophyid mite, Calacarus flagelliseta, which induces upward curling of the leaf margin at the end of the summer when populations reach high densities. A survey and three manipulative field experiments demonstrated that (1) leaf rolls induce a consistent shift in the spatial distribution of spider mites and their predators, the coccinellid Stethorus siphonulus Kapur, the predatory mites Phytoseiulus spp., and the tangle-web building spider Nesticodes rufipes Lucas; (2) the overall abundance of spiders increases on leaves with rolls; (3) the specialist predators Stethorus and Phytoseiulus inhabit the rolls in response to their spider mite prey; and (4) the spider inhabits the rolls in response to the architecture of the roll itself. This study shows the importance of indirect effects in structuring a terrestrial community of herbivores.
Fournier
Valérie
V
Department of Entomology, University of California, Davis, CA 95616, USA. valfourn@yahoo.ca
Rosenheim
Jay A
JA
Brodeur
Jacques
J
Laney
Lee O
LO
Johnson
Marshall W
MW
D000818:Animals; D029441:Carica / Q000033:anatomy & histology*; D005247:Feeding Behavior; D020387:Food Chain; D018515:Plant Leaves / Q000033:anatomy & histology*; D010945:Plants, Edible; D011157:Population Dynamics; D013112:Spiders; D040102:Tetranychidae