title: Behavioral Responses of Laricobius spp. and Hybrids (Coleoptera: Derodontidae) to Hemlock Woolly Adelgid and Adelgid Host Tree Odors in an Olfactometer.
abstract: The predatory species Laricobius nigrinus (Fender) and Laricobius osakensis (Shiyake and Montgomery) (Coleoptera: Derodontidae) have been released for biological control of hemlock woolly adelgid (Adelges tsugae; Hemiptera: Adelgidae) in eastern North America. L. osakensis is native to Japan, whereas L. nigrinus is endemic to the Pacific Northwest of the United States and Canada. After release, L. nigrinus was found to hybridize with the native eastern species, Laricobius rubidus (LeConte). The purpose of this study is to observe prey location behaviors of these three Laricobius species and L. nigrinus × L. rubidus (Ln × Lr) hybrids. Olfactometer bioassays were used to test response to host odors of adelgid-infested eastern hemlock, uninfested eastern hemlock, and uninfested eastern white pine. Predators reacted in the olfactometer more quickly when adelgid-infested foliage was included as a choice. L. nigrinus preferred infested eastern hemlock over uninfested eastern white pine, and L. rubidus preferred uninfested eastern white pine over uninfested eastern hemlock. Laricobius hybrids did not show a preference for foliage types known to be primary adelgid hosts (eastern hemlock and eastern white pine). Unequal preference by species of Laricobius for host trees of different adelgid prey could therefore be maintaining Laricobius species barriers despite hybridization. L. osakensis for this study were reared in the laboratory, whereas other species in this study were collected from the field, yet still were attracted to infested and uninfested eastern hemlock. This species also responded most quickly in the olfactometer, which is encouraging for successful biological control with this species.
authors: The Rubenstein School of Environment and Natural Resources, The University of Vermont, 81 Carrigan Dr., Burlington, VT 05405.
authors: Arielle L
authors: AL
authors: Arsenault
authors: U.S. Department of Agriculture, Forest Service, Northern Research Station, 51 Mill Pond Rd., Hamden, CT 06513.
authors: Nathan P
authors: NP
authors: Havill
authors: U.S. Department of Agriculture, Forest Service, Southern Research Station, 200 W.T. Weaver Blvd., Asheville, NC 28804.
authors: Albert E
authors: AE
authors: Mayfield
authors: The Rubenstein School of Environment and Natural Resources, The University of Vermont, 81 Carrigan Dr., Burlington, VT 05405. U.S. Department of Agriculture, Forest Service, Northern Research Station, 51 Mill Pond Rd., Hamden, CT 06513. kwallin@uvm.edu.
authors: Kimberly F
authors: KF
authors: Wallin
mesh_terms: D000818:Animals; D001681:Biological Assay; D061046:Biological Control Agents; D002678:Chimera; D002755:Choice Behavior; D001517:Coleoptera / Q000502:physiology*; D006430:Hemiptera; D009812:Odorants; D028223:Pinus; D011235:Predatory Behavior; D012903:Smell; D028225:Tsuga / Q000469:parasitology*
chemical_list: D061046:Biological Control Agents
keywords: Laricobius spp.; Tsuga canadensis; biological control; host location behavior; hybridization