title: Bionomics and Vector Potential of Culex thriambus (Diptera: Culicidae) Mosquitoes in Lake County, California.
abstract: California statewide West Nile virus (WNV) minimum infection rates in Culex thriambus Dyar mosquitoes are high; however, few specimens are submitted and tested each year, as their distribution seems limited to larval habitats along riparian systems. To evaluate the role of Cx. thriambus in the amplification, maintenance, and overwintering of WNV in Lake County, CA, the bionomics and vector potential of the species was investigated during 2014 and 2015. Culex thriambus was the most abundant mosquito species, with 1,153 adults and 7,624 immatures collected by vacuum aspiration and dip sampling, respectively, at the primary study site. Detection of WNV in four mosquito pools during September through November coincided with peak seasonality. Females entered and maintained a reproductive diapause during winter under field and seminatural conditions. Diapause was initiated in the majority of Cx. thriambus females by October and was terminated by 30 March. Some parous females (7.1%) and those in host-seeking arrest (7.1%) were collected throughout the winter period. An accrual of 679.51 degree-days (°D) was necessary for diapause termination under seminatural conditions. Culex thriambus females fed on 16 different avian species during spring and summer, and no mammalian feeds were detected. West Nile viral RNA was detected in four of 42 Cx. thriambus pools tested during June through November and infection rates ranged from 3.53-28.15/1,000 tested. In summary, WNV transmission may be increased along riparian corridors throughout California where Cx. thriambus mosquitoes remain relatively abundant.
authors: Lake County Vector Control District, 410 Esplanade St., Lakeport, CA 95453 (bnelms@lcvcd.org; danielle@lcvcd.org; michelle@lcvcd.org; bryan@lcvcd.org; jjscott@lcvcd.org) bnelms@lcvcd.org.
authors: Brittany M
authors: BM
authors: Nelms
authors: University of the Pacific, 3601 Pacific Ave., Stockton, CA 95211 (tthiemann@PACIFIC.EDU; f22raptor94@gmail.com).
authors: Tara C
authors: TC
authors: Thiemann
authors: Lake County Vector Control District, 410 Esplanade St., Lakeport, CA 95453 (bnelms@lcvcd.org; danielle@lcvcd.org; michelle@lcvcd.org; bryan@lcvcd.org; jjscott@lcvcd.org).
authors: Danielle N
authors: DN
authors: Bridges
authors: University of the Pacific, 3601 Pacific Ave., Stockton, CA 95211 (tthiemann@PACIFIC.EDU; f22raptor94@gmail.com).
authors: Alan E
authors: AE
authors: Williams
authors: Lake County Vector Control District, 410 Esplanade St., Lakeport, CA 95453 (bnelms@lcvcd.org; danielle@lcvcd.org; michelle@lcvcd.org; bryan@lcvcd.org; jjscott@lcvcd.org).
authors: Michelle L
authors: ML
authors: Koschik
authors: Lake County Vector Control District, 410 Esplanade St., Lakeport, CA 95453 (bnelms@lcvcd.org; danielle@lcvcd.org; michelle@lcvcd.org; bryan@lcvcd.org; jjscott@lcvcd.org).
authors: Bonnie M
authors: BM
authors: Ryan
authors: Lake County Vector Control District, 410 Esplanade St., Lakeport, CA 95453 (bnelms@lcvcd.org; danielle@lcvcd.org; michelle@lcvcd.org; bryan@lcvcd.org; jjscott@lcvcd.org).
authors: Jamesina J
authors: JJ
authors: Scott
mesh_terms: D000818:Animals; D002140:California; D003465:Culex / Q000502:physiology* / Q000821:virology*; D005247:Feeding Behavior; D005260:Female; D007303:Insect Vectors / Q000502:physiology* / Q000821:virology*; D008297:Male; D011157:Population Dynamics; D012621:Seasons; D012726:Sexual Behavior, Animal; D014902:West Nile virus / Q000302:isolation & purification*
keywords: California; Culex thriambus; West Nile virus; bionomics; diapause