title: Nickel hyperaccumulation as an elemental defense of Streptanthus polygaloides (Brassicaceae): influence of herbivore feeding mode.
abstract: No study of a single nickel (Ni) hyperaccumulator species has investigated the impact of hyperaccumulation on herbivores representing a variety of feeding modes. Streptanthus polygaloides plants were grown on high- or low-Ni soils and a series of no-choice and choice feeding experiments was conducted using eight arthropod herbivores. Herbivores used were two leaf-chewing folivores (the grasshopper Melanoplus femurrubrum and the lepidopteran Evergestis rimosalis), a dipteran rhizovore (the cabbage maggot Delia radicum), a xylem-feeder (the spittlebug Philaenus spumarius), two phloem-feeders (the aphid, Lipaphis erysimi and the spidermite Trialeurodes vaporariorum) and two cell-disruptors (the bug Lygus lineolaris and the whitefly Tetranychus urticae). Hyperaccumulated Ni significantly decreased survival of the leaf-chewers and rhizovore, and significantly reduced population growth of the whitefly cell-disruptor. However, vascular tissue-feeding insects were unaffected by hyperaccumulated Ni, as was the bug cell-disruptor. We conclude that Ni can defend against tissue-chewing herbivores but is ineffective against vascular tissue-feeding herbivores. The effects of Ni on cell-disruptors varies, as a result of either variation of insect Ni sensitivity or the location of Ni in S. polygaloides cells and tissues.
authors.affiliation: Department of Biological Sciences, Auburn University, AL 36849-5407, USA.
authors.forename: Edward M
authors.initials: EM
authors.lastname: Jhee
authors.forename: Robert S
authors.initials: RS
authors.lastname: Boyd
authors.forename: Micky D
authors.initials: MD
authors.lastname: Eubanks
mesh_terms: D000818:Animals; D001181:Arthropods / Q000187:drug effects / Q000502:physiology; D001693:Biological Transport, Active; D019607:Brassicaceae / Q000378:metabolism* / Q000469:parasitology*; D004032:Diet; D007313:Insecta / Q000187:drug effects* / Q000502:physiology*; D009532:Nickel / Q000378:metabolism* / Q000633:toxicity*
chemical_list: D009532:Nickel