This page has only limited features, please log in for full access.

Unclaimed
William E. Walton
Department of Entomology, University of California, Riverside, CA

Honors and Awards

The user has no records in this section


Career Timeline

The user has no records in this section.


Short Biography

The user biography is not available.
Following
Followers
Co Authors
The list of users this user is following is empty.
Following: 0 users

Feed

Journal article
Published: 28 May 2021 in Journal of Medical Entomology
Reads 0
Downloads 0

The western mosquitofish, Gambusia affinis (Baird & Girard), has been used worldwide for the control of larval mosquitoes for more than 100 yr. We found that the western encephalitis mosquito, Culex tarsalis Coquillett (Diptera: Culicidae), can detect the presence of G. affinis in oviposition sites based on associated chemicals, leading to a decrease in the number of egg rafts laid. Three volatile chemical compounds were identified in the headspace above the water where G. affinis had been held for 24 h. Oviposition bioassays conducted using standards of the volatile compounds identified (dimethyl disulfide [DMDS], dimethyl trisulfide [DMTS], and S-methyl methanethiosulphonate) found that females reduced oviposition only when low concentrations of DMTS were present, but this response was not consistent across all trials and concentrations tested. DMDS, DMTS, and S-methyl methanethiosulphonate are known bacterial metabolic waste products and may be the source of the compounds. Two nonvolatile compounds of interest were found to be present in the Gambusia-exudate water. After tasting Cx. tarsalis were deterred from ovipositing onto Gambusia-treated water from which the bacteria had been removed by filtration, indicating that the kairomone may consist of nonvolatile compound(s). One of the nonvolatile compounds isolated from the Gambusia-treated water has a benzene ring structure similar to that of cholesterol but the structure of the two nonvolatile deterrents remains to be fully characterized. Our research shows that three volatile compounds and two nonvolatile compounds are present in water associated with G. affinis (Poeciliidae: Gambusia) and affect the oviposition behavior of Cx. tarsalis in laboratory bioassays.

ACS Style

Adena M Why; Dong-Hwan Choe; William E Walton. Identification of Chemicals Associated Gambusia affinis (Cyprinodontiformes: Poeciliidae), and Their Effect on Oviposition Behavior of Culex tarsalis (Diptera: Culicidae) in the Laboratory. Journal of Medical Entomology 2021, 1 .

AMA Style

Adena M Why, Dong-Hwan Choe, William E Walton. Identification of Chemicals Associated Gambusia affinis (Cyprinodontiformes: Poeciliidae), and Their Effect on Oviposition Behavior of Culex tarsalis (Diptera: Culicidae) in the Laboratory. Journal of Medical Entomology. 2021; ():1.

Chicago/Turabian Style

Adena M Why; Dong-Hwan Choe; William E Walton. 2021. "Identification of Chemicals Associated Gambusia affinis (Cyprinodontiformes: Poeciliidae), and Their Effect on Oviposition Behavior of Culex tarsalis (Diptera: Culicidae) in the Laboratory." Journal of Medical Entomology , no. : 1.

Journal article
Published: 19 November 2019 in Journal of Medical Entomology
Reads 0
Downloads 0

Considerable previous research has focused on predator-associated semiochemicals and how they affect mosquito oviposition behavior. However, most of this work has been done without taking into consideration either the natural density of the predators or how other semiochemicals in aquatic environments might affect the responses of gravid mosquitoes. The influence of mosquitofish density, source water (tap vs pond), presence of freshly laid egg rafts, and removal of a putative source of semiochemicals (bacteria) on oviposition by Culex tarsalis Coquillett (Diptera: Culicidae) was studied in laboratory bioassays. Culex tarsalis females were deterred from laying egg rafts on water that contained semiochemicals associated with Gambusia affinis (Baird & Girard), but this deterrence was not strongly associated with the density of fish used to condition aged tap water. The number of egg rafts laid onto Gambusia-exudate water made with either tap water (density < 1 fish per liter) or pond water was typically ≥ 50% of that onto water that did not house mosquitofish. Gravid mosquitoes tested individually did not reduce oviposition onto Gambusia-exudate water as compared to controls. Likewise, oviposition by females with ablated wings did not differ significantly between Gambusia-exudate water and controls. Oviposition onto filter-sterilized Gambusia-exudate water was reduced relative to unfiltered water, suggesting that semiochemicals deterring egg-laying were still present after bacteria were removed. Taken together, these findings suggest that the responses of gravid Cx. tarsalis to chemicals from habitats containing mosquitofish are complex and the origin of the semiochemicals present in the Gambusia-exudate water needs to be elucidated.

ACS Style

Adena M Why; William E Walton. Oviposition Behavior of Culex tarsalis (Diptera: Culicidae) Responding to Semiochemicals Associated with the Western Mosquitofish, Gambusia affinis (Cyprinodontiformes: Poecilliidae). Journal of Medical Entomology 2019, 57, 343 -352.

AMA Style

Adena M Why, William E Walton. Oviposition Behavior of Culex tarsalis (Diptera: Culicidae) Responding to Semiochemicals Associated with the Western Mosquitofish, Gambusia affinis (Cyprinodontiformes: Poecilliidae). Journal of Medical Entomology. 2019; 57 (2):343-352.

Chicago/Turabian Style

Adena M Why; William E Walton. 2019. "Oviposition Behavior of Culex tarsalis (Diptera: Culicidae) Responding to Semiochemicals Associated with the Western Mosquitofish, Gambusia affinis (Cyprinodontiformes: Poecilliidae)." Journal of Medical Entomology 57, no. 2: 343-352.

Journal article
Published: 22 December 2017 in Journal of Medical Entomology
Reads 0
Downloads 0

Commercially available formulations of two entomopathogenic fungi, Beauveria bassiana (Bals.-Criv.) Vuill. (Hypocreales: Clavicipitaceae) and Metarhizium anisopliae (Metchnikoff) Sorokin (Hypocreales: Clavicipitaceae), were assessed for control of Culex quinquefasciatus Say (Diptera: Culicidae) in underground storm drain systems (USDS) in the Coachella Valley of southern California. Each of three treatments, the two fungi or a water control, was applied to 1 m2 of vertical wall at eight USDS sites in spring and autumn of 2015. Fungal infectivity and lethality were assessed at 1 d and 1, 2, and 4 wk post-application. Overnight bioassays using adult lab-reared female mosquitoes were carried out on the treated USDS wall areas and then mosquitoes were held in the laboratory for up to 21 d to allow fungal infections to be expressed. Postmortem fungal sporulation was assessed up to 2 wk at 100% humidity. Mosquito–fungal interactions also were assessed in bioassays of the three treatments on filter paper exposed to USDS conditions during autumn. Metarhizium anisopliae killed mosquitoes faster than B. bassiana; nevertheless, both freshly applied formulations caused greater than 80% mortality. Fungal persistence declined significantly after 1 wk under USDS conditions, but some infectivity persisted for more than 4 wk. Beauveria bassiana was more effective against Cx. qinquefasciatus in the spring, while M. anisopliae was more effective in the cooler conditions during autumn. USDS environmental conditions (e.g., temperature, relative humidity, standing water) influenced fungal-related mortality and infection of Cx. quinquefasciatus. The utility of these fungal formulations for mosquito abatement in the Coachella Valley and implications for fungal control agents in USDS environments are discussed.

ACS Style

David A Popko; Jennifer A Henke; Bradley A Mullens; William E Walton. Evaluation of Two Entomopathogenic Fungi for Control of Culex quinquefasciatus (Diptera: Culicidae) in Underground Storm Drains in the Coachella Valley, California, United States. Journal of Medical Entomology 2017, 55, 654 -665.

AMA Style

David A Popko, Jennifer A Henke, Bradley A Mullens, William E Walton. Evaluation of Two Entomopathogenic Fungi for Control of Culex quinquefasciatus (Diptera: Culicidae) in Underground Storm Drains in the Coachella Valley, California, United States. Journal of Medical Entomology. 2017; 55 (3):654-665.

Chicago/Turabian Style

David A Popko; Jennifer A Henke; Bradley A Mullens; William E Walton. 2017. "Evaluation of Two Entomopathogenic Fungi for Control of Culex quinquefasciatus (Diptera: Culicidae) in Underground Storm Drains in the Coachella Valley, California, United States." Journal of Medical Entomology 55, no. 3: 654-665.

Journal article
Published: 26 September 2016 in Water
Reads 0
Downloads 0

The impact of small-stature alkali bulrush (Bolboschoenus maritimus) and two hydroperiod treatments (early season raised water level or ambient water level) on mosquito production and water quality was studied in replicate 0.09 ha free water surface (FWS) treatment wetlands. Following reconfiguration of a 1-ha constructed wetland into a system with six replicate wetlands, bulrush was planted on 0.5-m centers in three 5-m wide bands in each wetland in summer, 2012. Open water and the low density of emergent vegetation effectively limited mosquito production from the bands of B. maritimus in each wetland during summer and autumn of year one. After the autumnal senescence of the bulrush culms, water levels were raised in half of the wetlands during winter and early spring to enhance sinking of dead bulrush biomass to reduce harborage for mosquitoes. Macrophyte coverage continued to increase in both hydroperiod treatments during year two, but non-bulrush species proliferated and eventually overgrew B. maritimus. Immature mosquito abundance in dipper samples from wetlands in the raised water level treatment was greater than from wetlands in the constant water level treatment. During spring of year two, adult mosquito production was associated with volunteer vegetation in the center of the test cells and averaged 6–18 mosquitoes m−2·day−1, approximately twice that of the other treatment. Hydrological regime did not significantly affect water quality performance (removal of nitrogen, phosphorus and chemical oxygen demand) in the wetlands. Alkali bulrush can persist in shallow water (depth < 0.2 m), but did not persist in deeper zones (mean depth > 0.4 m) of the wetlands and after comparatively large stature grasses and cattails colonized the wetlands. Raised planting beds interspersed with zones of deeper water are recommended to facilitate persistence of alkali bulrush and to limit proliferation of superior competitors.

ACS Style

William E. Walton; Dagne Duguma; Min Tao; David A. Popko; Scott Nygren. Integrated Mosquito Management in Experimental Constructed Wetlands: Efficacy of Small-Stature Macrophytes and Fluctuating Hydroperiod. Water 2016, 8, 421 .

AMA Style

William E. Walton, Dagne Duguma, Min Tao, David A. Popko, Scott Nygren. Integrated Mosquito Management in Experimental Constructed Wetlands: Efficacy of Small-Stature Macrophytes and Fluctuating Hydroperiod. Water. 2016; 8 (10):421.

Chicago/Turabian Style

William E. Walton; Dagne Duguma; Min Tao; David A. Popko; Scott Nygren. 2016. "Integrated Mosquito Management in Experimental Constructed Wetlands: Efficacy of Small-Stature Macrophytes and Fluctuating Hydroperiod." Water 8, no. 10: 421.

Comparative study
Published: 01 June 2016 in Journal of the American Mosquito Control Association
Reads 0
Downloads 0

Gravid mosquito collections were compared among several large-volume (infusion volume ≥35 liters) gravid trap designs and the small-volume (infusion volume = 6 liters) Centers for Disease Control and Prevention (CDC) gravid trap used routinely by vector control districts for vector and pathogen surveillance. The numbers of gravid Culex quinquefasciatus, Cx. tarsalis, and Cx. stigmatosoma collected by large gravid traps were greater than by the CDC gravid trap during nearly all overnight trials. Large-volume gravid traps collected on average 6.6-fold more adult female Culex mosquitoes compared to small-volume CDC gravid traps across 3 seasons during the 3 years of the studies. The differences in gravid mosquito collections between large-versus small-volume gravid traps were greatest during spring, when 8- to 56-fold more Culex individuals were collected using large-volume gravid traps. The proportion of gravid females in collections did not differ appreciably among the more effective trap designs tested. Important determinants of gravid trap performance were infusion container size and type as well as infusion volume, which determined the distance between the suction trap and the infusion surface. Of lesser importance for gravid trap performance were the number of suction traps, method of suction trap mounting, and infusion concentration. Fermentation of infusions between 1 and 4 wk weakly affected total mosquito collections, with Cx. stigmatosoma collections moderately enhanced by comparatively young and organically enriched infusions. A suction trap mounted above 100 liters of organic infusion housed in a 121-liter black plastic container collected the most gravid mosquitoes over the greatest range of experimental conditions, and a 35-liter infusion with side-mounted suction traps was a promising lesser-volume alternative design.

ACS Style

David A. Popko; William E. Walton. Large-Volume Gravid Traps Enhance Collection of Culex Vectors. Journal of the American Mosquito Control Association 2016, 32, 91 -102.

AMA Style

David A. Popko, William E. Walton. Large-Volume Gravid Traps Enhance Collection of Culex Vectors. Journal of the American Mosquito Control Association. 2016; 32 (2):91-102.

Chicago/Turabian Style

David A. Popko; William E. Walton. 2016. "Large-Volume Gravid Traps Enhance Collection of Culex Vectors." Journal of the American Mosquito Control Association 32, no. 2: 91-102.

Journal article
Published: 27 May 2016 in Journal of Vector Ecology
Reads 0
Downloads 0

The developmental time and survival to eclosion of Anopheles hermsi Barr & Guptavanij fed monotypic and mixed diets of ten food types were examined in laboratory studies. Larvae fed monotypic diets containing animal detritus (freeze-dried rotifers, freeze-dried Daphnia pulicaria, and TetraMin® fish food flakes) and the mixotrophic protistan Cryptomonas ovata developed faster and survived better than larvae that were fed other monotypic diets. Survival to adulthood of larvae fed several concentrations of the diatom Planothidium (=Achnanthes) lanceolatum was poor (1% C20 polyunsaturated fatty acids as total fat, but regardless of essential fatty acid content, algae that produced mucilage and filaments that sank out of the feeding zone were poor quality diets.

ACS Style

Donald A. Beasley; William E. Walton. Suitability of monotypic and mixed diets for Anopheles hermsi larval development. Journal of Vector Ecology 2016, 41, 80 -89.

AMA Style

Donald A. Beasley, William E. Walton. Suitability of monotypic and mixed diets for Anopheles hermsi larval development. Journal of Vector Ecology. 2016; 41 (1):80-89.

Chicago/Turabian Style

Donald A. Beasley; William E. Walton. 2016. "Suitability of monotypic and mixed diets for Anopheles hermsi larval development." Journal of Vector Ecology 41, no. 1: 80-89.

Journal article
Published: 24 July 2015 in BMC Microbiology
Reads 0
Downloads 0

The native microflora associated with mosquitoes have important roles in mosquito development and vector competence. Sequencing of bacterial V3 region from 16S rRNA genes across the developmental stages of Culex mosquitoes (early and late larval instars, pupae and adults) was used to test the hypothesis that bacteria found in the larval stage of Culex are transstadially transmitted to the adult stage, and to compare the microbiomes of field-collected versus laboratory-reared mosquitoes. Beta diversity analysis revealed that bacterial community structure differed among three life stages (larvae, pupae and adults) of Culex tarsalis. Although only ~2 % of the total number of bacterial OTUs were found in all stages, sequences from these OTUs accounted for nearly 82 % of the total bacterial sequences recovered from all stages. Thorsellia (Gammaproteobacteria) was the most abundant bacterial taxon found across all developmental stages of field-collected Culex mosquitoes, but was rare in mosquitoes from laboratory-reared colonies. The proportion of Thorsellia sequences in the microbiomes of mosquito life stages varied ontogenetically with the greatest proportions recovered from the pupae of C. tarsalis and the lowest from newly emerged adults. The microbiome of field-collected late instar larvae was not influenced significantly by differences in the microbiota of the habitat due to habitat age or biopesticide treatments. The microbiome diversity was the greatest in the early instar larvae and the lowest in laboratory-reared mosquitoes. Bacterial communities in early instar C. tarsalis larvae were significantly more diverse when compared to late instar larvae, pupae and newly emerged adults. Some of the bacterial OTUs found in the early instar larvae were also found across developmental stages. Thorsellia dominated the bacterial communities in field-collected immature stages but occurred at much lower relative abundance in adults. Differences in microbiota observed in larval habitats did not influence bacterial community profiles of late instar larvae or adults. However, bacterial communities in laboratory-reared C. tarsalis larvae differed significantly from the field. Determining the role of Thorsellia in mosquitoes and its distribution across different species of mosquitoes warrants further investigation.

ACS Style

Dagne Duguma; Michael W. Hall; Paul F Rugmanjones; Richard Stouthamer; Olle Terenius; Josh D. Neufeld; William E. Walton. Developmental succession of the microbiome of Culex mosquitoes. BMC Microbiology 2015, 15, 1 -13.

AMA Style

Dagne Duguma, Michael W. Hall, Paul F Rugmanjones, Richard Stouthamer, Olle Terenius, Josh D. Neufeld, William E. Walton. Developmental succession of the microbiome of Culex mosquitoes. BMC Microbiology. 2015; 15 (1):1-13.

Chicago/Turabian Style

Dagne Duguma; Michael W. Hall; Paul F Rugmanjones; Richard Stouthamer; Olle Terenius; Josh D. Neufeld; William E. Walton. 2015. "Developmental succession of the microbiome of Culex mosquitoes." BMC Microbiology 15, no. 1: 1-13.

Journal article
Published: 11 November 2013 in Journal of Vector Ecology
Reads 0
Downloads 0

The impact of emergent macrophyte species and crepuscular sprinkler disturbance on mosquito abundance over a 2-year period was measured in wetland mesocosms. Mosquito oviposition and abundance of immature mosquitoes and aquatic invertebrates were monitored in monotypic plots of small-stature (height of mature stands 2 m) California bulrush (Schoenoplectus californicus) without or with daily sprinkler showers to deter mosquito egg laying. Relative to wetlands without operational sprinklers, oviposition by culicine mosquitoes was reduced by > 99% and immature mosquito abundance was reduced by > 90% by crepuscular sprinkler applications. Mosquito abundance or distribution in wetlands did not differ between the two bulrush species subjected to the sprinkler treatment. Alkali bulrush wetlands without daily sprinkler treatments contained more egg rafts but significantly fewer mosquito larvae than did California bulrush wetlands. Predaceous damselfly naiads were 3-5 times more abundant in alkali bulrush than in California bulrush. Stem density, rate of spread, and autumnal mortality of alkali bulrush were higher than for California bulrush. Replacement of large emergent macrophytes by smaller species may enhance the efficacy of integrated mosquito management programs to reduce mosquito-transmitted disease cycles associated with multipurpose constructed wetlands used worldwide for water reclamation and habitat restoration.

ACS Style

David A. Popko; William E. Walton. Small-stature emergent macrophytes and crepuscular sprinkler disturbance reduce mosquito abundance in wetland mesocosms. Journal of Vector Ecology 2013, 38, 379 -389.

AMA Style

David A. Popko, William E. Walton. Small-stature emergent macrophytes and crepuscular sprinkler disturbance reduce mosquito abundance in wetland mesocosms. Journal of Vector Ecology. 2013; 38 (2):379-389.

Chicago/Turabian Style

David A. Popko; William E. Walton. 2013. "Small-stature emergent macrophytes and crepuscular sprinkler disturbance reduce mosquito abundance in wetland mesocosms." Journal of Vector Ecology 38, no. 2: 379-389.

Journal article
Published: 01 March 2013 in Journal of the American Mosquito Control Association
Reads 0
Downloads 0

The distribution and abundance of emerging Culex spp. were assessed within narrow (width: 3 m) and wide (width: 20 m) bands of California bulrush (Schoenoplectus californicus) and in the open water adjacent to emergent vegetation in 2 marshes of an ammonia-dominated wastewater treatment wetland in southern California. Emerging mosquitoes were collected along transects perpendicular to the path of water flow at 3 distances (1.5, 5, and 10 m) from the vegetation-open water interface in the wide bands of emergent vegetation, at the center of narrow bands of emergent vegetation, and at 1.5 m from the edge of emergent vegetation in the open water. The width of vegetation bands (3 vs. 20 m) influenced the effectiveness of integrated mosquito management practices, especially the application of mosquito control agents. Mosquito production from the 2 marshes also differed up to 14-fold, suggesting that the distance between the shorelines (62 vs. 74 m) of each marsh also influenced the efficacy of mosquito control agents applied from the shore and boats. Hot spots of mosquito production (75424 female Culex/m2/day) were found within the wide bands of bulrush. During summer, the relative abundance of Culex stigmatosoma among emerging mosquitoes increased from the periphery to the center of wide bands of emergent vegetation. Culex erythrothorax emergence rates were comparatively similar among the transects in the wide bands of emergent vegetation. Culex tarsalis adults increased in number from the periphery to the center of wide bands of bulrush and, in May, were > 95% of emerged mosquitoes.

ACS Style

William E. Walton; David A. Popko; Alex R. Van Dam; Andrea Merrill. Distribution of Culex Species in Vegetation Bands of a Constructed Wetland Undergoing Integrated Mosquito Management. Journal of the American Mosquito Control Association 2013, 29, 69 -73.

AMA Style

William E. Walton, David A. Popko, Alex R. Van Dam, Andrea Merrill. Distribution of Culex Species in Vegetation Bands of a Constructed Wetland Undergoing Integrated Mosquito Management. Journal of the American Mosquito Control Association. 2013; 29 (1):69-73.

Chicago/Turabian Style

William E. Walton; David A. Popko; Alex R. Van Dam; Andrea Merrill. 2013. "Distribution of Culex Species in Vegetation Bands of a Constructed Wetland Undergoing Integrated Mosquito Management." Journal of the American Mosquito Control Association 29, no. 1: 69-73.

Journal article
Published: 01 May 2012 in Ecological Engineering
Reads 0
Downloads 0
ACS Style

William E. Walton; David A. Popko; Alex R. Van Dam; Andrea Merrill; Jeff Lythgoe; Barry Hess. Width of planting beds for emergent vegetation influences mosquito production from a constructed wetland in California (USA). Ecological Engineering 2012, 42, 150 -159.

AMA Style

William E. Walton, David A. Popko, Alex R. Van Dam, Andrea Merrill, Jeff Lythgoe, Barry Hess. Width of planting beds for emergent vegetation influences mosquito production from a constructed wetland in California (USA). Ecological Engineering. 2012; 42 ():150-159.

Chicago/Turabian Style

William E. Walton; David A. Popko; Alex R. Van Dam; Andrea Merrill; Jeff Lythgoe; Barry Hess. 2012. "Width of planting beds for emergent vegetation influences mosquito production from a constructed wetland in California (USA)." Ecological Engineering 42, no. : 150-159.

Journal article
Published: 20 December 2011 in Wetlands Ecology and Management
Reads 0
Downloads 0

Constructed wetland technology has broad applications for the treatment of many types of wastewaters and provides an ecological approach to mitigate the release of nutrients and toxic materials into the environment. However, design features, maintenance activities and the characteristics of the wastewater undergoing treatment contribute differentially to potential levels of mosquito production and, consequently, to threats to human and animal health from mosquito-borne pathogens. Of the variables typically considered when designing free-water surface constructed wetlands for the improvement of water quality of municipal and agricultural wastewaters, organic loading (i.e., biochemical oxygen demand, total suspended solids), nutrients (nitrogen and phosphorus), and the configuration and maintenance of emergent vegetation can have strong effects on mosquito production. The production of Culex vectors of encephalitides and filarial worms is directly related to loading rates of organic matter and bottom-up enrichment of larval mosquito resources and their interaction with design features and management practices that reduce the physical and biological factors causing mortality of immature mosquitoes. As loading rates of organic matter and nutrients decline, the diversity of mosquitoes produced by treatment wetlands tends to increase and the relative abundance of Anopheles species, which are capable of vectoring the causative agents of malaria, increases in temperate man-made wetlands. Habitat features and management practices that create intermittently inundated substrate can lead to the production of other mosquitoes (i.e., Aedes, Psorophora) with floodwater life histories. Constructed wetland technology is expected to play an increasing role in water treatment and reclamation in tropical and subtropical countries where virulent mosquito-borne pathogens already cause significant levels of morbidity and mortality.

ACS Style

William E. Walton. Design and management of free water surface constructed wetlands to minimize mosquito production. Wetlands Ecology and Management 2011, 20, 173 -195.

AMA Style

William E. Walton. Design and management of free water surface constructed wetlands to minimize mosquito production. Wetlands Ecology and Management. 2011; 20 (3):173-195.

Chicago/Turabian Style

William E. Walton. 2011. "Design and management of free water surface constructed wetlands to minimize mosquito production." Wetlands Ecology and Management 20, no. 3: 173-195.

Journal article
Published: 01 November 2009 in Journal of Medical Entomology
Reads 0
Downloads 0

Species-specific differences in the responses of egg-laying mosquitoes (Diptera: Culicidae) to the presence of fish exudates in oviposition sites in laboratory bioassays have been related to the likelihood of encountering mosquito-eating fish in natural oviposition sites. We examined the responses of egg-laying mosquitoes to the presence of larvivorous fish in oviposition sites to test this hypothesis in the field. The number of Culex tarsalis Coquillett egg rafts laid on mesocosms (15.5 m2; 8 m3) containing caged mosquitofish (0.066 Gambusia affinis per liter) was reduced by 84% relative to mesocosms lacking fish. Egg-laying Culex quinquefasciatus Say did not differentiate significantly between comparatively small (0.11 m2) oviposition sites containing water conditioned with mosquitofish (0.3 G. affinis per liter) versus aged reservoir water. Cx. quinquefasciatus egg rafts were not collected from the larger mesocosms, and Cx. tarsalis egg rafts were rarely collected from the smaller oviposition sites. Oviposition preferences for characteristics of aquatic habitats that lack fish (e.g., small size, semipermanence, and high levels of organic enrichment in which hypoxic conditions are prevalent) may limit the coexistence of immature stages of some mosquito species such as Cx. quinquefasciatus and insectivorous fish. Mosquito species such as Cx. tarsalis that also use comparatively large water bodies as developmental sites may have evolved the ability to detect the presence of predatory fish.

ACS Style

William E. Walton; Alex R. Van Dam; David A. Popko. Ovipositional responses of two Culex (Diptera: Culicidae) species to larvivorous fish. Journal of Medical Entomology 2009, 46, 1338 -1343.

AMA Style

William E. Walton, Alex R. Van Dam, David A. Popko. Ovipositional responses of two Culex (Diptera: Culicidae) species to larvivorous fish. Journal of Medical Entomology. 2009; 46 (6):1338-1343.

Chicago/Turabian Style

William E. Walton; Alex R. Van Dam; David A. Popko. 2009. "Ovipositional responses of two Culex (Diptera: Culicidae) species to larvivorous fish." Journal of Medical Entomology 46, no. 6: 1338-1343.

Comparative study
Published: 01 December 2007 in Journal of the American Mosquito Control Association
Reads 0
Downloads 0

Two 6-wk trials were conducted in 28-m2 earthen ponds to compare the efficacy of the arroyo chub, Gila orcutti, to the mosquitofish, Gambusia affinis, as a biological control agent for mosquitoes and a possible replacement for the mosquitofish in sensitive watersheds of southern California. The mosquitofish population growth rate was 1.73 times greater than the arroyo chub population growth rate; however, greater reproduction by the mosquitofish did not result in significantly better reduction of mosquitoes than was provided by the comparatively small populations of arroyo chub. On average across a 6-wk study in the spring, both larvivorous fishes reduced the abundance of 3rd and 4th instars by 4- to 5-fold compared to that observed in the control ponds that lacked fish but contained few invertebrate predators. The abundance of nontarget microinvertebrates in ponds containing the mosquitofish was only 7% of that in ponds containing the arroyo chub during the summer, but did not differ significantly between the fish species treatments when zooplankton was comparatively more abundant during the spring. Even though the number of individuals produced by each fish species during 6 wk in the spring was greater than for fish stocked in the summer, species-specific population growth rates in the spring study (individuals/individual/d; mosquitofish, 0.077; arroyo chub, 0.044) were only slightly higher than in the summer (individuals/individual/d; mosquitofish, 0.068; arroyo chub, 0.039) indicating that differences in the number of fish stocked contributed primarily to the differences in final population size between spring and summer studies. The arroyo chub is native to the South Coastal drainages in California and should be considered as a viable alternative to the mosquitofish for integrated mosquito management programs in riverine wetlands and sensitive watersheds of southern California.

ACS Style

Alex R. Van Dam; William E. Walton. COMPARISON OF MOSQUITO CONTROL PROVIDED BY THE ARROYO CHUB (GILA ORCUTTI) AND THE MOSQUITOFISH (GAMBUSIA AFFINIS). Journal of the American Mosquito Control Association 2007, 23, 430 -441.

AMA Style

Alex R. Van Dam, William E. Walton. COMPARISON OF MOSQUITO CONTROL PROVIDED BY THE ARROYO CHUB (GILA ORCUTTI) AND THE MOSQUITOFISH (GAMBUSIA AFFINIS). Journal of the American Mosquito Control Association. 2007; 23 (4):430-441.

Chicago/Turabian Style

Alex R. Van Dam; William E. Walton. 2007. "COMPARISON OF MOSQUITO CONTROL PROVIDED BY THE ARROYO CHUB (GILA ORCUTTI) AND THE MOSQUITOFISH (GAMBUSIA AFFINIS)." Journal of the American Mosquito Control Association 23, no. 4: 430-441.

Comparative study
Published: 01 November 2006 in Journal of Medical Entomology
Reads 0
Downloads 0

The succession of the planktonic bacterial community during the colonization by Culex (Diptera: Culicidae) mosquitoes of 0.1-ha treatment wetlands was studied using denaturing gradient gel electrophoresis (DGGE) methodology. Relationships between apparent bacterial diversity and ecological factors (water quality, total bacterial counts, and immature mosquito abundance) were determined during a 1-mo flooding period. Analysis of DGGE banding patterns indicated that days postflooding and temporal changes in water quality were the primary and secondary determinants, respectively, of diversity in bacterial communities. Lower levels of diversity were associated with later postflood stages and increases in ammoniacal nitrogen concentration and total bacterial counts. Diversity was therefore most similar for bacteria present on the same sampling date at wetland locations with similar flooding regimes and water quality, suggesting that wastewater input was the driving force shaping bacterial communities. Comparatively small changes in bacterial diversity were connected to natural processes as water flowed through the wetlands. Greater immature mosquito abundance coincided with less diverse communities composed of greater total numbers of bacteria. Five individual DGGE bands were directly associated with fluctuations in mosquito production, and an additional 16 bands were associated with hydrological aspects of the environment during the rise and fall of mosquito populations. A marked decline in mosquito numbers 21 d after inundation may have masked associations of bacterial communities and mosquito recruitment into the sparsely vegetated wetlands. DGGE was an effective tool for the characterization of bacteria in mosquito habitat in our study, and its potential application in mosquito ecology is discussed.

ACS Style

David A. Popko; Suk-Kyun Han; Brian Lanoil; William E. Walton. Molecular Ecological Analysis of Planktonic Bacterial Communities in Constructed Wetlands Invaded by Culex (Diptera: Culicidae) Mosquitoes. Journal of Medical Entomology 2006, 43, 1153 -1163.

AMA Style

David A. Popko, Suk-Kyun Han, Brian Lanoil, William E. Walton. Molecular Ecological Analysis of Planktonic Bacterial Communities in Constructed Wetlands Invaded by Culex (Diptera: Culicidae) Mosquitoes. Journal of Medical Entomology. 2006; 43 (6):1153-1163.

Chicago/Turabian Style

David A. Popko; Suk-Kyun Han; Brian Lanoil; William E. Walton. 2006. "Molecular Ecological Analysis of Planktonic Bacterial Communities in Constructed Wetlands Invaded by Culex (Diptera: Culicidae) Mosquitoes." Journal of Medical Entomology 43, no. 6: 1153-1163.