title: Exploring the Effects of Plant Odors, from Tree Species of Differing Host Quality, on the Response of Lymantria dispar Males to Female Sex Pheromones.
abstract: A widely accepted hypothesis for host-plant selection in herbivorous insects is that ovipositing females select host-plants that maximize the survival and performance of their offspring. However, numerous studies indicate that this is not always the case for polyphagous species. Lymantria dispar is a highly polyphagous forest defoliator and has flightless females in some subspecies, resulting in a limited capacity to make host-choices. Males of other Lepidopteran species utilize a combination of sexual pheromones and plant volatiles in their mating choices and exhibit preferences among plant species. We explored the behavior of L. dispar males towards sexual pheromone in the presence and absence of plant volatiles and their ability to discriminate between two plant species with different degrees of suitability for their offspring: a suboptimal host (Pinus sylvestris), and an optimal host (Quercus robur). In no-choice wind tunnel assays, we found that rates of male success in locating a pheromone source were not altered by the presence of plant odors; however, the time spent by males searching for the pheromone source after reaching the full length of the tunnel was reduced by more than 50% in the presence of plant volatiles. In dual choice assays, males exhibited a clear preference for a combination of pheromones and plant volatiles over the pheromone alone. However, we did not find evidence of an innate ability to discriminate between the odors of optimal and suboptimal host plants. We discuss possible ecological and evolutionary explanations for these observations.
authors.affiliation: ETH Zürich, Department of Environmental Systems Science, Schmelzbergstarsse 9, 8092, Zürich, Switzerland.|Institute of Agriculture and Environment, Massey University, Private Bag 11222, Palmerston North, 4442, New Zealand.
authors.forename: Andrea Clavijo
authors.initials: AC
authors.lastname: McCormick
authors.affiliation: ETH Zürich, Department of Environmental Systems Science, Schmelzbergstarsse 9, 8092, Zürich, Switzerland.|Kantonaler Pflanzenschutzdienst, Landwirtschaftliches Institut des Kantons Freiburg, Route de Grangeneuve, 311725, Posieux, Switzerland.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Heyer
authors.affiliation: ETH Zürich, Department of Environmental Systems Science, Schmelzbergstarsse 9, 8092, Zürich, Switzerland.
authors.forename: James W
authors.initials: JW
authors.lastname: Sims
authors.affiliation: ETH Zürich, Department of Environmental Systems Science, Schmelzbergstarsse 9, 8092, Zürich, Switzerland.
authors.forename: Mark C
authors.initials: MC
authors.lastname: Mescher
authors.affiliation: ETH Zürich, Department of Environmental Systems Science, Schmelzbergstarsse 9, 8092, Zürich, Switzerland. consuelo.demoraes@usys.ethz.ch.
authors.forename: Consuelo M
authors.initials: CM
authors.lastname: De Moraes
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D002755:Choice Behavior / Q000187:drug effects; D004357:Drug Synergism; D005260:Female; D058507:Host Specificity; D007915:Lepidoptera / Q000187:drug effects*; D008297:Male; D009812:Odorants / Q000032:analysis*; D028223:Pinus / Q000737:chemistry*; D029963:Quercus / Q000737:chemistry*; D012724:Sex Attractants / Q000494:pharmacology*; D055549:Volatile Organic Compounds / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D012724:Sex Attractants; D055549:Volatile Organic Compounds
keywords: Gypsy moth; Host-choice; Plant volatiles; Polyphagous insects; Sexual pheromones