title: Interactions Among Latitude, Nematode Parasitization, and Female Sirex nigricornis (Hymenoptera: Siricidae) Fitness.
abstract: Sirex nigricornis F. (Hymenoptera: Siricidae) is an innocuous pine-inhabiting woodwasp native to eastern North America, utilizing dead or dying pine trees as hosts. Although S. nigricornis F. does not cause economic damage, a closely related species, Sirex noctilio, was discovered in New York in 2004 and has continually spread throughout the northeastern United States and southern Canada, threatening the multi-billion-dollar pine timber industry of the southeastern United States and raising interest about potential interactions with native woodwasps and associated mortality agents. A non-sterilizing strain of the biological control agent, Deladenus siricidicola Bedding (Tylenchida: Neotylenchidae), was introduced along with S. noctilio but is not inhibiting the spread or establishment of S. noctilio A North American congener, Deladenus proximus Bedding, has been recently isolated from S. noctilio and shows promise as a biological control agent. To better understand the potential of D. proximus as a control agent for S. noctilio, we measured and dissected nearly 1,200 S. nigricornis females from Arkansas and Mississippi and evaluated differences among collection location with regard to nematode virulence, woodwasp body size, and egg load. Body size and egg load were related to collection location, and nematode infestation resulted in significantly smaller females who produced significantly fewer eggs. Female woodwasps, especially those collected in Arkansas, were often fully sterilized by nematodes, and a higher percent sterilization was inversely related to body size and fewer eggs. We propose field studies to test the nematode's ability to sterilize S. noctilio in the northeastern United States.
authors.affiliation: Division of Forestry, Minnesota Department of Natural Resources, 1201 E Hwy 2, Grand Rapids, MN 55744 (jessica.hartshorn@state.mn.us) jessica.hartshorn@state.mn.us.|Department of Entomology, University of Arkansas, 319 Agriculture Bldg, Fayetteville, AR 72701 (lgallig@uark.edu; fstephen@uark.edu).
authors.forename: Jessica A
authors.initials: JA
authors.lastname: Hartshorn
authors.affiliation: Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Mississippi State, MS 39762 (kdc39@uclive.ac.nz; jriggins@entomology.msstate.edu).|College of Food, Agricultural, and Natural Resource Sciences, University of Minnesota, 432 Hodson Hall, 1980 Folwell Ave, St. Paul, MN 55108.
authors.forename: Kevin D
authors.initials: KD
authors.lastname: Chase
authors.affiliation: Department of Entomology, University of Arkansas, 319 Agriculture Bldg, Fayetteville, AR 72701 (lgallig@uark.edu; fstephen@uark.edu).
authors.forename: Larry D
authors.initials: LD
authors.lastname: Galligan
authors.affiliation: Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Mississippi State, MS 39762 (kdc39@uclive.ac.nz; jriggins@entomology.msstate.edu).
authors.forename: John J
authors.initials: JJ
authors.lastname: Riggins
authors.affiliation: Department of Entomology, University of Arkansas, 319 Agriculture Bldg, Fayetteville, AR 72701 (lgallig@uark.edu; fstephen@uark.edu).
authors.forename: Fred M
authors.initials: FM
authors.lastname: Stephen
mesh_terms: D063147:Animal Distribution; D000818:Animals; D001131:Arkansas; D049628:Body Size; D005260:Female; D056084:Genetic Fitness; D005843:Geography; D006927:Hymenoptera / Q000235:genetics / Q000469:parasitology*; D012098:Reproduction; D017187:Tylenchida / Q000502:physiology*
keywords: Deladenus; Sirex noctilio; biological control; forest entomology; invasive species