Selected Works @ University of Nebraska, Lincoln

Not Your Parents' Library Video

DeeAnn Allison — Fri, 10 Feb 2012 07:10:40 PST

A video with Buffy, a student at the University of Nebraska-Lincoln shows her parents how to do research the "NU" way. Using a computer in her dorm room she is able to search the catalog to find books, renew books, and save search preferences so she can repeat them without having to re-enter the searches later. She also shows her parents how she saves time writing papers by finding articles using a new tool that searches across many databases at the same time and then connects to the full article, which she reads on her computer. She also demonstrates how she can automatically save the references in a database that manages her citations for importing into her papers. She explains to her parents how she can chat with a librarian anytime over the web and order materials through interlibrary loan all without leaving her dorm room. Finally, they take a trip to the library where they find equipment and help to produce videos for Buffy's classroom presentation. The parents are amazed at how things have changed since they were in college. This video was produced by the Computing Operations & Research Services of the University of Nebraska-Lincoln Libraries for National Library Week in 2007. It stars Joan Barnes, Alicia Dostal, Randal Fulkerson, Dwight Leggott, and Reed Rawhouser, actual staff and students at UNL.

Database Selection: One Size Does Not Fit All

DeeAnn Allison et al. — Fri, 10 Feb 2012 07:10:39 PST

With increasing costs and decreasing budgets, it is important for librarians to make sound purchasing decisions for electronic resources. What factors are important to consider in making a decision? How can librarians balance these factors, which may appear to be contradictory, and also meet the expectations of administrators, staff, and users? This article describes a strategy for making delivery decisions that address local conditions, pricing, feature options, hardware costs, and network availability. Finally, a model is presented for evaluating the decision based on dollar requirements and local issues.

Index Relativity and Patron Search Strategy

DeeAnn Allison et al. — Fri, 10 Feb 2012 07:10:38 PST

This study compares searches in two different keyword indexes with similar content. Search results are dependent on the quality of the search strategy, the search engine execution, and the content the search is run against. This study examines the degree to which changing the search engine execution with only slight changes in index content would have on search results. The results indicate that search engine execution has a dramatic impact on the number of matches for most searches. Analysis also reveals that user search strategy did not change even though the way the search engine executes the search changed dramatically and new features and commands that they could use to refine their searches were added. Users appear to be ignoring search help screens and continue to do basic searches that negatively affect the number of relevant matches. Providing more features for constructing better searches will not necessarily result in better search strategy.

Information Portals: The Next Generation Catalog

DeeAnn Allison — Fri, 10 Feb 2012 07:10:37 PST

Libraries today face an increasing challenge: to provide relevant information to diverse populations with differing needs, while competing with Web search engines like Google. In 2009 the University of Nebraska-Lincoln (UNL) Libraries joined with other libraries and Innovative Interfaces as development partners to design a new type of discovery tool. Information portals as a concept best supports the research and instructional needs of our communities by organizing and presenting information that incorporates licensed databases, text, multimedia, and other relevant sources. The discovery tool under examination by UNL, Encore, integrates searches of the catalog, locally created full-text and image sources, and articles from licensed databases, with navigation options that facilitate narrowing and expanding search results. This information portal development is an ongoing process with the goal of providing a tool that is as easy to use as Web search engines but preserves the quality that library users expect. This article explores the requirements for an information portal and describes the challenges UNL faced when implementing Encore. Statistics from the initial implementation are presented, along with recommendations for future usability studies to evaluate where additional improvements should be made

Computer Network Security and ARL Libraries

DeeAnn Allison et al. — Fri, 10 Feb 2012 07:10:36 PST

This article will review current recommendations for computer security practices for staff computing, summarize current practices in US Association of Research Libraries and propose further areas to explore.

Piracy, Slavery, and Assimilation: Women in Early Modern Captivity Literature

David C. Moberly — Thu, 09 Feb 2012 16:18:28 PST

This thesis examines a hitherto neglected body of works featuring female characters enslaved in Islamicate lands. During the sixteenth and seventeenth centuries, many Englishmen and women were taken captive by pirates and enslaved in what is now the Middle East and North Africa. Several writers of the time created narratives and dramas about the experiences of such captives. Recent scholarship has brought to light many of these works and pointed out their importance in establishing what was still a young, unsure, and developing English identity in this early period. Most of this scholarship, however, has dealt with narratives of the male captivity experience, leaving literary representations of women's experiences in captivity largely unexplored. I fill the gap in this thesis, using both captivity narratives, such as Emanuel D’Aranda’s History of Algiers, and dramas, including Robert Daborne’s A Christian Turn’d Turke, Philip Massinger’s The Renegado, and Lodowick Carlell’s Osmond the Great Turk. I argue that early modern captivity literature maintained a gendered double-standard that allowed men to reaffirm the strength of their European and Christian identities despite the power of Islamic hegemony while simultaneously exposing the faithless flaws of the “weaker sex,” creating within their literature female captive characters who ultimately betray their “true,” European identities.

Adviser: Stephen Buhler

Emerging Chemicals and Analytical Methods (2006)

Matthew C. Morley et al. — Thu, 09 Feb 2012 15:23:11 PST

This review summarizes peer-reviewed literature related to analysis, occurrence, and fate of emerging chemical contaminants in the water environment. The review focuses on the following broad categories of emerging contaminants: pharmaceuticals and personal care products (PPCPs); endocrine disrupting compounds (EDCs), including hormones, surfactants, and plasticizers; and brominated flame retardants (BFRs). Although many of the cited articles refer to multiple types of contaminants (particularly hormones and pharmaceuticals), each article is summarized in only one section. Articles pertaining to specific treatment methods, risk assessments, or biological effects are not included in this review, and articles covering disinfection byproducts (DBPs), fluorinated compounds, and organometallics are not reviewed as in past years. Because of the ever-increasing volume and scope of literature pertaining to emerging contaminants, this review should not be considered to be comprehensive; however, a broad range of literature that is relevant to environmental engineers and scientists is summarized.

Remediating RDX-Contaminated Ground Water with Permanganate: Laboratory Investigations for the Pantex Perched Aquifer

M. L. Adam et al. — Thu, 09 Feb 2012 15:23:10 PST

Ground water beneath the U.S. Department of Energy Pantex Plant is contaminated with the high explosive RDX (hexahydro-1,3,5- trinitro-1,3,5 triazine). The USDOE Innovative Treatment and Remediation Demonstration (ITRD) program identified in situ oxidation by permanganate as a technology fit for further investigation. We evaluated the efficacy of KMnO₄ to transform and mineralize RDX by determining degradation kinetics and carbon mass balances using ¹⁴C-RDX. Aqueous RDX solutions (2–5 mg L^–1) and RDX-contaminated slurries (50% solids, w/v) were treated with KMnO₄ at 1000, 2000, 4000, and 20,000 mg L^–1. Treating an aqueous RDX solution of 2.8 mg L^–1 with 20,000 mg KMnO₄ L^–1 decreased RDX to 0.1 mg L^–1 within 11 d while cumulative mineralization proceeded for 14 d until 87% of the labeled carbon was trapped as ¹⁴CO₂. Similar cumulative mineralization was obtained when Pantex aquifer material was included in the solution matrix. Other experiments using 4000 mg KMnO₄ L^–1 showed that initial RDX concentrations (1.3–10.4 mg L^–1) or initial pH (4–11) had little effect on reaction rates. Attempts to identify RDX degradates and reaction products showed that N₂O was a product of permanganate oxidation and constituted 20 to 30% of the N balance. Time-course measurements of a ¹⁴C-RDX solution treated with KMnO₄ revealed few ¹⁴C-labeled degradates but through liquid chromatography–mass spectrometry (LC–MS) analysis, we present evidence that 4-nitro-2,4-diazabutanol is formed. Aquifer microcosm studies confirmed that the transformation products not mineralized by KMnO₄ were much more biodegradable than parent RDX. These results indicate permanganate can effectively transform and mineralize RDX in the presence of aquifer material and support its use as an in situ chemical oxidation treatment for the Pantex perched aquifer.

Occurrence of sulfonamide antimicrobials in private water wells in Washington County, Idaho, USA

Angela L. Batt et al. — Thu, 09 Feb 2012 15:23:09 PST

County (Weiser, Idaho) were collected to assess the impact of a nearby confined animal feeding operation (CAFO) on the quality of the local groundwater. All six samples were found contaminated by two veterinary antimicrobials, sulfamethazine (at concentrations from 0.076 to 0.22 μg/l) and sulfadimethoxine (at concentrations from 0.046 to 0.068 μg/l). These groundwater samples also contained elevated concentrations of nitrate and ammonium. Three of the sampled wells have nitrate levels that exceeded the maximum contaminant level set by the US Environmental Protection Agency for drinking water, with nitrate concentration as high as 39.1 mg/l. All but one well showed nitrate, which instead contained ammonium at 1.22 mg/l. Analysis of the nitrate and ammonium in these samples by isotopic ratio mass spectrometry indicated δ¹⁵N characteristic of an animal or human waste source. Results from this study underscore the role of CAFO as an important source of antibiotic contamination of groundwater.

Herbicides in Ground Water beneath Nebraska’s Management Systems Evaluation Area

Roy F. Spalding et al. — Thu, 09 Feb 2012 15:23:07 PST

Profiles of ground water pesticide concentrations beneath the Nebraska Management Systems Evaluation Area (MSEA) describe the effect of 20 years of pesticide usage on ground water in the central Platte Valley of Nebraska. During the 6-yr (1991–1996) study, 14 pesticides and their transformation products were detected in 7848 ground water samples from the unconfined water table aquifer. Triazine and acetamide herbicides applied on the site and their transformation products had the highest frequencies of detection. Atrazine [6-chloro-N-ethyl-N’-(1-methylethyl)-1,3,5-triazine-2,4,-diamine] concentrations decreased with depth and ground water age determined with ³H/³He dating techniques. Assuming equivalent atrazine input during the past 20 yr, the measured average changes in concentration with depth (age) suggest an estimated half-life of >10 yr. Hydrolysis of atrazine and deethylatrazine (DEA; 2-chloro-4-amino-6-isopropylamino-s-triazine) to hydroxyatrazine [6-hydroxy-N-ethyl-N’-(1-methylethyl)-1,3, 5-triazine-2,4-diamine] appeared to be the major degradation route. Aqueous hydroxyatrazine concentrations are governed by sorption on the saturated sediments. Atrazine was detected in the confined Ogallala aquifer in ultra-trace concentrations (0.003μgL^–1); however, the possibility of introduction during reverse circulation drilling of these deep wells cannot be eliminated. In fall 1997 sampling, metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-meth- ylethyl) acetamide] was detected in 57% of the 230 samples. Metolachlor oxanilic acid [(2-ethyl-6-methylphenyl)(2-methoxy-1-methylethyl) amino]oxo-acetic acid] was detected in most samples. In ground water profiles, concentrations of metolachlor ethane sulfonic acid [2-[(ethyl- 6-methylphenyl)(2-methoxy-1-methylethyl)amino]-2-oxo-ethanesul- fonic acid] exceeded those of deethylatrazine. Alachlor [2-chloro- N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide] was detected in <1% of the samples; however, alachlor ethane sulfonic acid [2-[(2,6- diethylphenyl)(methoxymethyl)amino]-2-oxoethanesulfonic acid] was present in most samples (63%) and was an indicator of past alachlor use.

Anaerobic Biodegradation of RDX and TCE: Single- and Dual-Contaminant Batch Tests

Travis S. M. Young et al. — Thu, 09 Feb 2012 15:23:06 PST

Several sites in the United States have groundwater contaminated with mixtures of high explosives and chlorinated solvents. This research examined the ability of two microbial cultures (anaerobic sludge and a facultative enrichment culture) to biodegrade single- and dual-contaminant mixtures of trichloroethene (TCE) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) under anaerobic conditions. In single component batch tests, both cultures degraded 0.6–1 mg RDX/L and its nitroso metabolites to below detection limits in <7 days. During initial 9-day TCE biodegradation>tests, the anaerobic sludge did not transform TCE, whereas the facultative culture transformed approximately 10% of the initial 1.4 mg TCE/L. Prior to dual-contaminant batch tests, both cultures were grown in the presence of TCE. Subsequently, both acclimated cultures rapidly biodegraded mixtures of RDX and TCE. Both cultures degraded RDX and RDX-nitroso compounds to below detection limits in <4 days. In the same>tests, TCE-acclimated anaerobic sludge converted TCE primarily to cis-dichloroethene (cis-DCE), while the acclimated facultative culture produced cis-DCE and other chlorinated metabolites. These preliminary results demonstrate that anaerobic bioremediation may be part of a feasible groundwater remediation alternative for mixtures of TCE and RDX.

Transformation of Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) by Permanganate

Chanat Chokejaroenrat et al. — Thu, 09 Feb 2012 15:23:05 PST

The chemical oxidant permanganate (MnO₄⁻) has been shown to effectively transform hexa-hydro-1,3,5-trinitro-1,3,5-triazine (RDX) at both the laboratory and fieldscales. We treated RDX with MnO₄⁻ with the objective of quantifying the effects of pH and temperature on destruction kinetics and determining reaction rates. A nitrogen mass balance and the distribution of reaction products were used to provide insight into reaction mechanisms. Kinetic experiments (at pH ~7, 25 °C) verifiedthat RDX−MnO₄⁻ reaction was first-order with respect to MnO₄⁻ and initial RDX concentration (second-order rate: 4.2 × 10⁻⁵ M⁻¹ s⁻¹). Batch experiments showed that choice of quenching agents (MnSO₄, MnCO₃, and H₂O₂) influenced sample pH and product distribution. When MnCO₃ was used as a quenching agent, the pH of the RDX−MnO₄⁻ solution was relatively unchanged and N₂O and NO₃⁻ constituted 94% of the N-containing products after 80% of the RDX was transformed. On the basis of the preponderance of N₂O produced under neutral pH (molar ratio N₂O/NO₃ ~5:1), no strong pH effect on RDX−MnO₄⁻ reaction rates, a lower activation energy than the hydrolysis pathway, and previous literature on MnO₄⁻ oxidation of amines, we propose that RDX−MnO₄⁻ reaction involves direct oxidation of the methylene group (hydride abstraction), followed by hydrolysis of the resulting imides, and decarboxylation of the resulting carboxylic acids to form N₂O, CO₂, and H₂O.

Emerging Chemicals and Analytical Methods (2005)

Matthew C. Morley et al. — Thu, 09 Feb 2012 15:23:04 PST

Emerging contaminants in the water environment continues to be a strong research focus, as evidenced by the abundance of material published during 2004. This review summarizes peer-reviewed literature pertinent to the field of environmental engineering and science and related to analysis, occurrence, and fate of emerging chemical contaminants in the water environment, focusing on the following broad categories of emerging organic contaminants: antibiotics and pharmaceuticals; personal care products ingredients (PCPIs), endocrine disrupting compounds (EDCs), halogenated compounds (particularly brominated and fluorinated compounds), and disinfection byproducts (DBPs). To maintain this focus, articles pertaining specifically to human and ecological toxicity, bioconcentration or bioaccumulation, risk assessments, and innovative treatment and destruction methods are not included in this review. Additionally, summaries of literature covering organometallic compounds are not included in this review as in past years. Because of the sheer volume of literature covered by this topic, this review should not be considered to be comprehensive.

Detection, Occurrence, and Fate of Emerging Contaminants in Agricultural Environments (2009)

Daniel D. Snow et al. — Thu, 09 Feb 2012 15:23:03 PST

Frequently studied environmental contaminants in agricultural systems include nutrients, sediments, and pesticides. These groups of contaminants typically occur at easily measured concentrations in surface run-off in agricultural watersheds. Nutrients, especially nitrogen, and pesticides have also been shown to impact ground water quality in areas susceptible to contamination. Less well-known are environmental impacts of newer classes of contaminants such as pharmaceuticals, steroids, antibiotic-resistance genes and prion proteins. These “emerging” contaminants clearly have potential to enter the environment and cause known or suspected adverse ecological or human health effects. Release of these contaminants to the environment often has occurred for quite some time, but methods for their detection at environmentally-relevant concentrations have only recently become available.

Evaluating the environmental fate and effects of emerging contaminants includes research on compounds such as surfactants, antibiotics and other pharmaceuticals, steroid hormones and other endocrine-disrupting compounds (EDCs), fire retardants, sunscreens, disinfection byproducts, new pesticides and pesticide metabolites, and naturally-occurring algal toxins. Detection of these contaminants in environmental matrices (water, wastewater, soils and sediments) is particularly challenging because of the low detection limits required, the complex nature of the samples, and difficulty in separating these compounds from interferences. New extraction and cleanup techniques, coupled with improvements in instrumental technologies provide the needed sensitivity and specificity for accurate measurement.

The objective of this paper is to review the literature published in 2008 evaluating the detection, fate, and occurrence of emerging contaminants, with a particular focus on emerging contaminants in agricultural systems. Relevant contaminants are EDCs (particularly hormones and anabolic steroids), antibiotics and other pharmaceuticals associated with wastewater, antibiotic resistance genes in bacteria and prions. Studies on pesticides and flame retardants are not reviewed unless they were evaluated in the same study.

Watershed Scale Impacts of Buffers and Upland Conservation Practices on Agrochemical Delivery to Streams

Thomas G. Franti et al. — Thu, 09 Feb 2012 15:23:02 PST

Conservation buffers are designed to reduce sediment and agrichemical runoff to surface water. Much is known about plot and field scale effectiveness of buffers; but little is known about their watershed scale impact. Our objective was to estimate the watershed scale impact of grass buffers by comparing sediment and agrichemical losses from two adjacent 141-165 hectare watersheds, one with conservation buffers and one without. Rainfall derived runoff events from 2002-2003 were monitored for water runoff, TSS, phosphorous and atrazine loss. A conservation-watershed included 0.8 km of grass buffers and 0.8 km of riparian forest buffer, ridge-tilled corn, corn-beans-alfalfa rotation, terraces and grassed waterways. A control-watershed had no buffers, disk-tilled, continuous corn and grassed waterways. The same application rate and method for atrazine to corn was used in each watershed. Total rainfall during the April-June monitoring period was similar in 2002 and 2003; however, the conservation-watershed produced only 27 mm of runoff, compared to 47 mm from the control. Over two years, TSS and phosphorous losses per hectare were reduced by 97% and 95%, respectively, in the conservation-watershed. Atrazine loss per hectare was 57% less in the conservation watershed. A separation technique showed that for 2002 other conservation practices reduced TSS by 84% and buffers reduced TSS by an additional 13% compared to the control. Similarly, other conservation practices reduced atrazine losses by 29% and buffers accounted for an additional 31%. On a watershed scale buffers can add benefit to a conservation system.

Field-Scale Cleanup of Atrazine and Cyanazine Contaminated Soil with a Combined Chemical-Biological Approach

Manmeet Waria et al. — Thu, 09 Feb 2012 15:23:01 PST

A former agrichemical dealership in western Nebraska was suspected of having contaminated soil. Our objective was to characterize and remediate the contaminated site by a combined chemical-biological approach. This was accomplished by creating contour maps of the on-site contamination, placing the top 60 cm of contaminated soil in windrows and mixing with a mechanical high-speed mixer. Homogenized soil containing both atrazine [6-chloro-N-ethyl-N´-isopropyl-1,3,5-triazine- 2,4-diamine] and cyanazine {2-[[4-chloro-6-(ethylamino)-1,3,5- triazin-2-yl] amino]-2-methylpropanenitrile} was then used in laboratory investigations to determine optimum treatments for pesticide destruction. Iron suspension experiments verified that zerovalent iron (Fe⁰) plus ferrous sulfate (FeSO₄•7H₂O) removed more than 90% of both atrazine and cyanazine within 14 days. Liquid chromatography/mass spectrometry (LC/ MS) analysis of the atrazine solution after treating with Fe⁰ and ferrous sulfate identified several degradation products commonly associated with biodegradation (i.e., deethlyatrazine (DEA), deisopropylatrazine (DIA), hydroxyatrazine (HA), and ammelines). Biological treatment evaluated emulsified soybean [Glycine max (L.) Merr.] oil (EOS) as a carbon source to stimulate biodegradation in static soil microcosms. Combining emulsified soybean oil with the chemical amendments resulted in higher destruction efficiencies (80–85%) and reduced the percentage of FeSO₄ needed. This chemical-biological treatment (Fe⁰ + FeSO₄ + EOS, EOS Remediation, Raleigh, NC) was then applied with water to 275 m³ of contaminated soil in the field. Windrows were tightly covered with clear plastic to increase soil temperature and maintain soil water content. Temporal sampling (0–342 d) revealed atrazine and cyanazine concentrations decreased by 79 to 91%. These results provide evidence that a combined chemical-biological approach can be used for on-site, field-scale treatment of pesticide-contaminated soil.

Herbicide Loading to Shallow Ground Water beneath Nebraska’s Management Systems Evaluation Area

Roy F. Spalding et al. — Thu, 09 Feb 2012 15:22:59 PST

Better management practices can counter deterioration of ground water quality. From 1991 through 1996 the influence of improved irrigation practices on ground water pesticide contamination was assessed at the Nebraska Management SystemsEvaluation Area. Three 13.4-ha corn (Zea mays L.) fields were studied: a conventional furrow-irrigated field, a surge-irrigated field and a center pivot–irrigated field, and a center pivot–irrigated alfalfa (Medicago sativa L.) field. The corn fields received one identical banded application of Bicep (atrazine [6-chloro-N-ethyl-N’-(1-methylethyl)-1,3,5-triazine-2,4,-diamine] _ metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamide]) annually; the alfalfa field was untreated. Ground water samples were collected three times annually from 16 depths of 31 multi-level samplers. Six years of sample data indicated that a greater than 50% reduction in irrigation water on the corn management fields lowered average atrazine concentrations in the upper 1.5 m of the aquifer downgradient of the corn fields from approximately 5.5 to <0.5 μg L^–1. Increases in deethylatrazine (DEA; 2-chloro-4-amino-6-isopropyl- amino-s-triazine) to atrazine molar ratios indicated that reducing water applications enhanced microbial degradation of atrazine in soil zones. The occurrence of peak herbicide loading in ground water was unpredictable but usually was associated with heavy precipitation within days of herbicide application. Focused recharge of storm runoff that ponded in the surge-irrigated field drainage ditch, in the upgradient road ditch, and at the downgradient end of the conventionally irrigated field was a major mechanism for vertical transport. Sprinkler irrigation technology limited areas for focused recharge and promoted significantly more soil microbial degradation of atrazine than furrow irrigation techniques and, thereby, improved ground water quality.

Detection, Occurrence and Fate of Emerging Contaminants in Agricultural Environments (2008)

Daniel D. Snow et al. — Thu, 09 Feb 2012 15:22:58 PST

Agricultural settings are affected by a unique set of environmental contaminants typically associated with land use. Nutrients and sediments from run-off and erosion have historically been, and continue to be, studied and understood with respect to their impacts to aquatic environments. Studies involving newer classes of contaminants, such as pharmaceuticals and steroids, are becoming more prevalent as methods for measuring these compounds become available. These “emerging” contaminants clearly have potential to enter the environment and cause known or suspected adverse ecological or human health effects. Release of these contaminants to the environment has occurred for quite some time, but methods for their detection at environmentally-relevant concentrations have only recently become available.

Studies involving emerging contaminants typically focus on the environmental fate and effects of surfactants, antibiotics and other pharmaceuticals, steroid hormones and other endocrine-disrupting compounds (EDCs), fire retardants, sunscreens, disinfection byproducts, new pesticides and pesticide metabolites, and naturally-occurring algal toxins. Detection of these and wastewater-related contaminants in environmental matrices (water, wastewater, soils and sediments) is particularly challenging because of the low detection limits required, the complex nature of the samples, and difficulty in separating these compounds from interferences. New extraction and clean-up techniques, coupled with improvements in instrumental technologies provide the needed sensitivity and specificity for accurate measurement.

The objective of this paper is to review the literature published in 2007 evaluating the detection, fate, and occurrence of emerging contaminants, with a particular focus on emerging contaminants in agricultural systems. Relevant contaminants are EDCs (particularly hormones and anabolic steroids), antibiotics and other pharmaceuticals associated with wastewater, antibiotic resistance genes in bacteria and prions. Studies on pesticides and flame retardants are not reviewed unless they were evaluated in the same study.

Occurrence and biological effect of exogenous steroids in the Elkhorn River, Nebraska, USA

Alan S. Kolok et al. — Thu, 09 Feb 2012 15:22:57 PST

Recent studies of surface waters in North America, Japan, and Europe have reported the presence of steroidogenic agents as contaminants. The current study has three objectives: 1) to determine if steroidogenic compounds are present in the Elkhorn River, 2) to determine if sediments collected from the Elkhorn River can act as a source of steroidogenic compounds to aquatic organisms, and 3) to determine if site-specific biological effects are apparent in the hepatic gene expression of fathead minnows. Evidence was obtained using three approaches: 1) deployment of polar organic chemical integrative samplers (POCIS), 2) deployment of caged fathead minnows, and 3) a laboratory experiment in which POCIS and fish were exposed to sediments from the deployment sites. Deployment sites included: the Elkhorn River immediately downstream from a Nebraska wastewater treatment plant, two waterways (Fisher Creek and Sand Creek) likely to be impacted by runoff from cattle feeding operations, and a reference site unlikely to be impacted by waste water inputs. The POCIS extracts were analyzed for a number of natural steroids and metabolites, as well as four different synthetic steroids: ethinylestradiol, zearalonol, 17β-trenbolone and melengestrol acetate. Estrogenic and androgenic metabolites, as well as progesterone and trace levels of melengestrol acetate were detected in POCIS deployed at each site. POCIS deployed in tanks containing field sediments from the four sites did not accumulate the synthetic steroids except for ethinylestradiol, which was detected in the aquarium containing sediments collected near the wastewater treatment plant. Fish deployed in Sand Creek and at the wastewater treatment plant experienced significantly elevated levels of gene expression for two genes (StAR and P450scc) relative to those deployed in Fisher Creek. Fish exposed to the sediments collected from Sand Creek had significantly higher levels of hepatic StAR and P450scc gene expression than did fish exposed to sediments from the two other field sites, as well as the no-sediment control tank. In conclusion: 1) detectable levels of steroidogenic compounds were detected in passive samplers deployed in the Elkhorn River, 2) sediments do not appear to be a significant source for steroidogenic compounds, and 3) site-specific differences were found in mRNA expression among the different treatment groups of fish; however, a functional explanation for these differences is not readily forthcoming.

Estrogenic Compounds Downstream from Three Small Cities in Eastern Nebraska: Occurrence and Biological Effect

Marlo K. Sellin et al. — Thu, 09 Feb 2012 15:22:56 PST

Recent studies have detected estrogenic compounds in surface waters in North America and Europe. Furthermore, the presence of estrogenic compounds in surface waters has been attributed, in some cases, to the discharge of wastewater treatment plant (WWTP) effluent. The primary objective of the current study was to determine if WWTP effluent contributes estrogens to the surface waters of Nebraska. A second objective of this study was to determine if estrogens were found in concentrations sufficient enough to manifest feminizing effects on fish. These objectives were satisfied by deploying polar organic chemical integrative samplers (POCIS) and caged fathead minnows at eight field sites. Deployment sites included: three reference sites (Pawnee Creek, the Little Blue River, and the Middle Loup River), two sites upstream of the WWTPs at Grand Island and Columbus, and three sites downstream of the WWTPs at Grand Island, Columbus, and Hastings. Following the seven day deployments, POCIS extracts were analyzed for estrone, 17β-estradiol, estriol and 17α-ethinylestradiol using liquid chromatography tandem mass spectrometry (LC/MS/MS). 17β-estradiol was detected in POCIS from six of the eight field sites with the greatest quantities recovered in POCIS deployed downstream from the Grand Island and Hastings WWTPs. Estrone was detected only in the POCIS deployed downstream from the Grand Island and Hastings WWTPs. Estrogenic effects were detected in caged minnows analyzed for the hepatic mRNA expression of two estrogen- responsive genes, vitellogenin (vg1) and estrogen receptor α (ERα). Fish deployed at the site where the greatest quantities of estrogens were recovered (Hastings) had significantly higher expression of both vg1 and ERα than fish deployed at any of the other sites. These results confirm that WWTP effluent contributes biologically significant levels of estrogens to Nebraska surface waters.

The occurrence of illicit and therapeutic pharmaceuticals in wastewater effluent and surface waters in Nebraska

Shannon L. Bartelt-Hunt et al. — Thu, 09 Feb 2012 15:22:55 PST

Passive samplers were used to develop semi-quantitative estimates of pharmaceutical concentrations in receiving waters influenced by wastewater effluent. The occurrence and estimated concentration of twenty illicit and therapeutic pharmaceuticals and metabolites in surface waters influenced by wastewater treatment plant (WWTP) discharge and in wastewater effluents in Nebraska were determined using Polar Organic Chemical Integrative Samplers (POCIS). Samplers were installed in rivers upstream and downstream of treated WWTP discharge at four sites and in a discharge canal at a fifth location. Based on differences in estimated concentrations determined from pharmaceuticals recovered from POCIS, WWTP effluent was found to be a significant source of pharmaceutical loading to the receiving waters. Effluents from WWTPs with trickling filters or trickling filters in parallel with activated sludge resulted in the highest observed in-stream pharmaceutical concentrations. Azithromycin, caffeine, 1,7-dimethylzanthine, carbamazepine, cotinine, DEET, diphenhydramine, and sulfamethazine were detected at all locations. Methamphetamine, an illicit pharmaceutical, was detected at all but one of the sampling locations, representing only the second report of methamphetamine detected in WWTP effluent and in streams impacted by WWTP effluent.

Comparison of Two Gelling Agents for Screwworm (Diptera: Calliphoridae) Larval Diets

David B. Taylor — Thu, 09 Feb 2012 15:16:22 PST

A sodium polyacrylamide polyacrylate gelling agent, Water-Lock G-400, and a galactan polysaccharide agent, carrageenan, were compared for solidifying larval diets of the screwworm, Cochliomyia hominivorax (Coquerel). Water-Lock diet produced larger pupae with less larval mortality than did carrageenan diet. Pupae from larvae reared on the Water-Lock diet exhibited higher emergence and produced adults with higher fecundity. Water-Lock diet also produced larger larvae at 56 h after oviposition. Densities in excess of 300 mg of eggs (16,200 eggs) per liter of Water-Lock gelled diet did not increase larval yield but did reduce larval weight and survival.

Mitochondrial DNA Variation among Muscidifurax spp. (Hymenoptera: Pteromalidae), Pupal Parasitoids of Filth Flies (Diptera)

David B. Taylor et al. — Thu, 09 Feb 2012 15:16:21 PST

Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and sequencing analyses were used to characterize an amplicon of ~625 bp in 4 of the 5 nominate species of Muscidifurax Girault & Sanders, pupal parasitoids of muscoid flies. A single polymorphic nucleotide site was observed among 2 samples of M. raptor Girault & Sanders. No sequence variation was observed among 3 samples of M. raptorellus Kogan & Legner. The sequence of M. uniraptor Kogan & Legner was identical to that of M. raptorellus. Nucleotide divergence among the Muscidifurax spp. ranged from 0.14 to 0.18 substitutions per nucleotide. Muscidifurax zaraptor Kogan & Legner exhibited multiple haplotypes, 2 of which were characterized by sequencing and 4 others by PCR-RFLP. The sequenced haplotypes differed by 0.08 nucleotide substitutions per site. Restriction site analysis indicated that nucleotide divergence ranged from 0.03 to 0.10 among all 6 haplotypes. Analysis of progeny from individual females indicated that the observed variation in M. zaraptor was caused by multiple haplotypes within individuals rather than differentiation among individuals. These results bring to question the specific status of M. uniraptor and indicate that the genus is native to the Western Hemisphere, and not introduced with their primary host, Musca domestica L, as previously proposed. Heteroplasmy and translocation of aportion of the mitochondrial genome to the nuclear genome are discussed as possible causes for the variation observed in M. zaraptor.

Identification of screwworm species by polymerase chain reaction-restriction fragment length polymorphism

David B. Taylor et al. — Thu, 09 Feb 2012 15:16:20 PST

Restriction fragment length polymorphisms in polymerase chain reaction amplified fragments (PCR-RFLP) of mitochondrial DNA were used to differentiate species of New World screwworms (Diptera : Calliphoridae) . Twenty-seven restriction enzymes were screened on five regions of mtDNA . Eleven restriction fragment length patterns differentiated New World screwworm, Cochliomyia hominivorax (Coquerel), from secondary screwworm, Cochliomyia macellaria (F.) . Five restriction fragment length patterns were polymorphic in C. hominivorax while all fragment patterns were fixed in C. macellaria. Diagnostic restriction fragment length patterns were used for species diagnosis, whereas intraspecific variable patterns were used to characterize field samples and laboratory strains . The PCR-RFLP technique is flexible with regard to developmental stage of the sample and method of preservation . We were able to characterize specimens of all life stages from egg to adult including larvae preserved in alcohol and pinned adults . PCR-RFLP is rapid and inexpensive, enabling specimens to be characterized within 24 h for less than $2 .50.

Population Genetics and Gene Variation in Primary and Secondary Screwworm (Diptera : Calliphoridae)

David B. Taylor et al. — Thu, 09 Feb 2012 15:16:19 PST

Allozyme variation in screwworm, Cochliomyia hominivorax (Coquerel), and secondary screwworm, C. macellaria (F.), populations from northwest Costa Rica was examined . Variability was observed in 11 of 13 enzyme loci and the frequency of the most common allele was <0.95 for 5 loci in screwworm . In secondary screwworm, 12 of 13 loci were variable and the frequency of the most common allele was <0.95 for 6 loci . Expected heterozygosities were 0.149 and 0.160 for screwworm and secondary screwworm, respectively. Goodness-of-fit statistics for Hardy-Weinberg equilibrium and Wrights F statistics indicated that both species are panmictic with no evidence of population substructuring. Nei ' s genetic distances were 0.000–0.001 for intraspecific comparisons and 0.899–0.916 for interspecific comparisons. The data indicate a high level of gene flow between populations within each species.

Genetic and Morphological Comparisons of New and Old World Populations of Spalangia Species (Hymenoptera: Pteromalidae)

David B. Taylor et al. — Thu, 09 Feb 2012 15:16:18 PST

The genetic similarity of New and Old World samples of Spalangia spp. (Hymenoptera: Pteromalidae) was examined using two ribosomalDNAregions. The species examined were Spalangia cameroni Perkins, Spalangia endius Walker, Spalangia gemina Bouček, Spalangia nigra Latreille, Spalangia nigroaenea Curtis, and Spalangia slovaca Bouček. Two species of Muscidifurax, Muscidifurax raptor Girault & Sanders and Muscidifurax zaraptor Kogan & Legner (Hymenoptera: Pteromalidae) were included as outgroup taxa. The internal transcribed spacer (ITS)-1 region was highly variable among Spalangia species with many insertions/deletions making alignment of the sequences difÞcult. The D2-D3 region of the 28s ribosomal gene and the nuclear rDNA 18s gene were more conserved and enabled phylogenetic analysis. No genetic differentiation was observed among S. cameroni and S. endius samples from Kazakhstan, Russia, and North America. New World samples of S. nigroaenea are genetically distinct from S. slovaca, a morphologically similar Old World species that is newly recorded from Kazakhstan and Russia. The intact 920 bp ITS-1 amplicon of S. nigroaenea was much larger than the 780-bp amplicon of S. slovaca. Kimura two-parameter genetic distance between the two species was 0.015 for the 28s region. Otherwise, the smallest genetic distance among recognized Spalangia species was 0.037 between S. endius and S. nigra. The genetic distance between M. raptor and M. zaraptor was 0.004. Based upon these results, the utility of the D2-D3 region of the 28s ribosomal gene is substantiated for differentiating species of Spalangia. The molecular analysis of the six Spalangia species revealed two groupings: S. nigroaenea and S. slovaca and S. cameroni and S. gemina. A third clade, S. endius and S. nigra, was observed, but bootstrap support was weak. These relationships were compared with those indicated by morphology and all agreed except possibly between S. endius and S. nigra, for which morphological evidence is equivocal. Morphological features are described and illustrated to distinguish the morphologically most similar species, S. nigra, S. nigroaenea, and S. slovaca, from each other and from other Spalangia spp.

Assessing Nuclear and Mitochondrial DNA Sequence Variation within Steinernema (Rhabditida: Steinernematidae)

Allen L. Szalanski et al. — Thu, 09 Feb 2012 15:16:17 PST

DNA sequence analysis was used to characterize the nuclear ribosomal DNA ITS1 region and a portion of the COII and 16S rDNA genes of the mitochondrial genome from Steinernema entomopathogenic nematodes. Nuclear ITS1 nucleotide divergence among seven Steinernema spp. ranged from 6 to 22%, and mtDNA divergence among five species ranged from 12 to 20%. No intraspecific variation was observed among three S. feltiae strains. Phylogenetic analysis of both nuclear and mitochondrial DNA sequences confirms the existing morphological relationships of several Steinernema species. Both the rDNA ITS1 and mtDNA sequences were useful for resolving relationships among Steinernema taxa.

Identification of Muscidifurax Spp. by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism

David B. Taylor et al. — Thu, 09 Feb 2012 15:16:15 PST

Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of the nuclear ribosomal ITS1 region was used to differentiate Muscidifurax (Hymenoptera: Pteromalidae) species which are parasitoids of filth fly pupae. Three restriction enzymes, Dpn 11, Mse I, and Taq I, produced restriction patterns which were diagnostic for the four species analyzed, M. raptor, M. raptorellus, M. uniraptor, and M. zaraptor. Seven other restriction enzymes were able to differentiate one or more of the species and can be used alone, or in combination with other enzymes, to verify identifications. No intraspecific variation was observed among the populations examined. The utility of the PCR-RFLP technique compared with other moIecuIar and biochemical diagnostic procedures is discussed.

Mitochondrial DNA variation in screwworm

David B. Taylor et al. — Thu, 09 Feb 2012 15:16:14 PST

Polymerase chain reaction-restriction fragment length polymorphism (PCRRFLP) analysis was used to characterize mitochondrial DNA (mtDNA) variation in screwworms, Cochliomyia hominivorax, and secondary screwworm, C. macellaria, from the Caribbean, North America and South America. Four amplicons, totaling 7.1 kb, were analysed with sixteen restriction enzymes. A total of 133 restriction sites was observed in the two species, 104 in C. hominivorax, of which nineteen were variable, and ninety-five in C. macellaria, none of which was variable. Fourteen mtDNA haplotypes were observed among eighteen C. hominivorax examined. Mean divergence between C. hominivorax haplotypes (d) was 0.0064 substitutions per base-pair and genotypic diversity (G) was 0 .97. Mean divergence between C. hominivorax and C. macellaria was 0.0824. Cochliomyia hominivorax haplotypes could be divided into three assemblages representing North America, South America, and Jamaica, based on UPGMA clustering with d values. The assemblages did not exhibit complete geographic fidelity. These data were discordant with previously published allozyme data indicating little differentiation between screwworm populations. A scenario invoking historically isolated populations coming into contact with the introduction and movement of European livestock is proposed to explain the observed population structure of screwworm.

Population Genetics and Gene Variation of Stable Fly Populations (Diptera: Muscidae) in Nebraska

Allen L. Szalanski et al. — Thu, 09 Feb 2012 15:16:13 PST

Genetic variation in stable fly, Stomoxys calcitrans (L.),populations from Nebraska, Canada, and Texas was sampled. Four of 12 allozyme loci were polymorphic, with an average of 1.7 alleles per locus. Observed and expected heterozygosities were 0.086 and 0.070,respectively. Nei's genetic distance between populations averaged 0.001 and ranged from 0.000 to 0.005. Wright's F statistics revealed greater variation within than among populations. Allele frequencies were homogeneous among temporal samples from a single population. Polymerasechain reaction—restriction fragment length polymorphism (PCR—RFLP) analysis of 6.4 kb of the mitochondrial DNA genome with 16 restriction enzymes revealed no variation in stable fly populations from Canada, Nebraska, and Texas. PCR—RFLP analysis of a 2.0-kb fragment of the nuclear ribosomal DNA internally transcribed spacer region also revealed no variation.The lack of genetic differentiation among stable fly populations indicates high levels of gene flow among populations. The low levels of variation observed with biochemical and molecular techniques are consistent with a genetic bottleneck during stable fly colonization of North America.

Genetics of the screwworm fly

David B. Taylor et al. — Thu, 09 Feb 2012 15:16:12 PST

Three spontaneous eye mutants of Cochliomyia hominivorax, the screwworm fly, are described and characterized. The mutants, yellow eye (ye), orange eye (or), and white eye (wh), segregate independently and are recessive. Yellow eye is recessively epistatlc to orange eye and dominantly epistatic to white eye. All three mutants have complete penetrance, are autosomal, and have little effect on fly viabillty under laboratory conditions.

Comparison of Gelled and Meat Diets for Rearing Screwworm, Cochliomyia hominivorax (Diptera: Calliphoridae), Larvae

David B. Taylor et al. — Thu, 09 Feb 2012 15:16:11 PST

A liquid diet solidified with an acrylamide-acrylate polymer gelling agent (Water-Lock) was compared with a standard meat diet for rearing screwworm, Cochliomyia hominivorax (Coquerel), larvae. Size and yield of larvae reared on gel diet were equal to, or greater than, those of larvae reared on meat diet. Duration of larval development was increased by ca. 13 h on gel diet; however, variability of pupal weight and larval survival over generations were reduced when gel diet was used. Larval size was also more uniform over the 3-d period when larvae leave the rearing medium to pupate (crawl-off). Gelled diet was more uniform over time than meat diet. In addition, gelled diet was easier to use, less objectionable to workers, and less expensive than meat diet.

Genetic similarity among pheromone and voltinism races of Ostrinia nubilalis (Hubner) (Lepidoptera: Crambidae)

P. C. R. G. Marcon et al. — Thu, 09 Feb 2012 15:16:10 PST

The genetic variability of seven European corn borer populations, Ostrinia nubilalis, from North America and Europe was assessed by polymerase chain reaction- restriction fragment length polymorphism (PCRRFLP) analysis and DNA sequencing. The nuclear ribosomal internal transcribed spacer 1 (ITS-1) region (≈ 500 base pair [bp]) and four mitochondrial (mtDNA) regions (1550 bp total) were examined. The smartweed borer, Ostrinia obumbratalis, and south-Western corn borer, Diatraea grandiosella, were used for comparisons. Of 106 restriction sites identified (80 in mtDNA and 26 in ITS-1), none differentiated geographical populations, pheromone races, or voltine ecotypes of the European corn borer. The lack of variation in the ITS-1 of European corn borer was confirmed by DNA sequence analysis. The genetic similarity of European corn borer populations, despite their wide geographical range and physiological differences, may be explained by a relatively recent origin for the voltinism and pheromone races, gene flow among races, and/or expansion from genetic bottlenecks.

Susceptibility of House Fly (Diptera: Muscidae) Larvae to Entomopathogenic Nematodes (Rhabditida: Heterorhabditidae, Steinernematidae

David B. Taylor et al. — Thu, 09 Feb 2012 15:16:09 PST

The potential for entomopathogenic nematodes to control flies in cattle feedlots was determined by screening 40 strains representing 8 species of Heterorhabditis Poinar and 5 species of Steinernema Travassos for virulence toward 3rd-instar house flies (maggots), Musca domestica L. None of the 22 strains of Heterorhabditis infecting maggots caused significant levels of mortality in a filter paper assay. Ten strains of Steinernema infected maggots, of which 7 strains--4 S. carpocapsa (Weiser), 2 S. feltiae (Filipjev), and 1 S. scapterisci (Nguyen & Smart) caused significant mortality. Ten Heterorhabditis strains and 10 Steinernema strains successllly reproduced for 22 generations in maggots. No difference was observed between 72-h survival of maggots and adult emergence. Six strains of Steinernema were selected for 10 generations on maggots and then compared with unselected lines. No difference in pathogenicity between selected and unselected lines was observed. Two strains of S. feltiae -- SN and UNK-36 -- and 2 of the best Heterorhabditis -- H. bacteriophora Poinar OSWEGO and H. megidis Poinar, Jackson & Klein HF-85 -- were tested in a fresh bovine manure substrate. All 4 strains produced significant fly mortality in the manure substrate, although the S. feltiae strains had significantly lower LC₅₀ values than did the Heterorhabditis spp. The most promising strain, S. feltiae SN, gave LC₅₀ and LC₉₉ values of 4 and 82 infective juveniles per maggot, respectively. These doses were equivalent to 2.7 and 55 infective juvenile per gram of manure and 5.1 and 104 infective juveniles per square centimeter of surface area. Infective juveniles capable of infecting greater wax moth larvae, Galleria mellonella (L.) survived in manure for up to 10 wk without hosts.

Genetic Relationship among Diabrotica Species (Coleoptera: Chrysomelidae) Based on rDNA and mtDNA Sequences

Allen L. Szalanski et al. — Thu, 09 Feb 2012 15:16:08 PST

Corn rootworms of the genus Diabrotica (Coleoptera: Chrysomelidae) are the most serious pest of corn in midwestern United States. Despite their economic importance, phylogenetic relationships within the genus remain unclear. Phylogenetic analysis of five Diabrotica species and subspecies was undertaken using DNA sequences of the nuclear rDNA first internal transcribed spacer region (ITS1) and a portion of the mtDNA cytochrome oxidase I and II genes (COI/COII). Parsimony and maximum likelihood analysis indicated that southern corn rootworm is sister to banded cucumber beetle, whereas, northern corn rootworm forms a distinct clade with western and Mexican corn rootworm. ITS1 and COI/COII were found to be useful markers for determining phylogenetic relationships among diabroticites.

Gusanos de raíz de maíz del genero Diabrotica (Coleoptera: Chrysomelidae) son la plaga de mayor seriedad para el maíz en el medio oeste de los Estados Unidos. A pesar de su importancia económica, relaciones filogenéticas dentro del genero permanecen confusas. Análisis filogenético de cinco especies de Diabrotica y subespecies fueron llevadas a cabo usando secuencias de ADN del [rDNA] nuclear primer orden, región [spacer] (ITS1) y una porción del [mtDNA cytochrome oxidase] I y II, genes (COI/ COII). Parsimonia y [cladograms] junta-vecinos indicaron que el gusano de raíz de maíz sureño es hermano del escarabajo bandeado del pepino, mientras que los gusanos de raíz de maíz norteños forman un [clade] diferente de con los gusanos de raíz de maíz occidentales y Mexicanos. ITS1 y COI/COII resultaron ser marcadores útiles para determinar las relaciones filogenéticas entre diabroticitas.

Population Genetics and Gene Variation in Secondary Screwworm (Diptera: Calliphoridae)

David B. Taylor et al. — Thu, 09 Feb 2012 15:16:07 PST

Allozyme variation in 4 populations of secondary screwworm, Cochliomyia macellaria (F.), representing North, Central, and South America was examined . Variability was observed in 12 of 13 enzyme loci, and the frequency of the most common allele was <0.95 for 6 loci . Observed and expected heterozygosities were 0.149 and 0.154, respectively. Nei's genetic distances were ≤ 0.001. Goodness-of-fit statistics for Hardy-Weinberg equilibrium and Wright's F_IS statistics indicated random mating within populations . Wright's F_ST statistics and chi-square contingency analyses indicated homogeneous gene frequencies among the populations. These data suggest that C. macellaria is a panmictic species with high levels of gene flow between populations.

Gelled Diet for Screwworm (Diptera: Calliphoridae) Mass Production

David B. Taylor et al. — Thu, 09 Feb 2012 15:16:06 PST

A rearing system based on a diet gelled with Water-Lock G400, a synthetic superabsorbent (poly(2-propenamide-co-2-propenoic acid, sodium salt))( WL), was compared with the standard rearing system (liquid diet suspended in acetate fibers) for the mass production of screwworms, Cochlomyia hominivorax (Coquerel). The WL rearing system yielded 2% heavier pupae, 32% higher egg to pupa survival, and required 54% less diet and 88% less labor than the standard rearing system. Other advantages of the WL system include reduced susceptibility to suboptimal environmental conditions and labor practices, and characteristics conducive to centralization and mechanization of rearing procedures.

Sugar Feeding in Adult Stable Flies

David B. Taylor et al. — Thu, 09 Feb 2012 15:16:05 PST

Adult stable flies (Stomoxys calcitrans L.) are known to feed readily on sugars in the laboratory. However, little is known concerning the extent of stable fly sugar feeding in wild populations. We examined the frequency of sugar feeding in stable flies collected on Alsynite sticky traps in rural and urban environments. In addition, stable flies were visually examined to determine whether blood was present in the gut. In laboratory studies, sugars were detectable with the anthrone technique in stable flies for ~3 d after being imbibed, and blood could be visually detected in the gut for 24-48 h after feeding. Twelve percent of the field-collected flies had detectable sugar with a higher percentage of the urban flies having sugar fed than the rural flies, 21% and 8%, respectively. Female flies sugar fed at a slightly higher rate than males, 13% versus 11%, respectively. Less than 1% of the field-collected flies had blood in their guts. The frequency of observable blood was slightly higher in flies collected in an urban environment compared with those collected in a rural environment and did not differ between male and female flies. The number of flies with both blood and sugar was slightly higher than would be expected based on the frequencies of each alone. Seasonal patterns of both sugar feeding and blood feeding were similar in the rural and urban environments; both peaked in the early summer, May to mid-June, and dropped through the summer and fall. Sugar feeding in the urban environment increased again in October.

Susceptibility of House Fly (Diptera: Muscidae) Larvae to Entomopathogenic Nematodes (Rhabditida: Heterorhabditidae, Steinernematidae)

David B. Taylor et al. — Thu, 09 Feb 2012 15:16:04 PST

The potential for entomopathogenic nematodes to control flies in cattle feedlots was determined by screening 40 strains representing 8 species of Heterorhabditis Poinar and 5 species of Steinemema Travassos for virulence toward 3rd-instar house flies (maggots), Musca domestica L. None of the 22 strains of Heterorhabditis infecting maggots caused significant levels of mortality in a filter paper assay. Ten strains of Steinemema infected maggots, of which 7 strains (4 S. carpocapsae (Weiser), 2 S.feltiae (Filipjev), and 1 S. scapterisci Nguyen & Smart) caused significant mortality. Ten Heterorhabditis strains and 10 Steinemema strains successfully reproduced for ≥ 2 generations in maggots. No difference was observed between 72-h survival of maggots and adult emergence. Six strains of Steinemema were selected for 10 generations on maggots and then compared with unselected lines. No difference in pathogenicity between selected and unselected lines was observed. Two strains of S. feltiae, SN and UNK-36, and 2 of the best Heterorhabditis strains, H. bacteriophora Poinar OSWEGO and H. megidis Poinar, Jackson & Klein HF -85 were tested in a fresh bovine manure substrate. All 4 strains produced significant fly mortality in the manure substrate, although the S. feltiae strains had significantly lower LC₅₀ values than did the Heterorhabditis spp. The most promising strain, S. feltiae SN, gave LC₅₀ and LC₉₉ values of 4 and 82 infective juveniles per maggot, respectively. These doses were equivalent to 2.7 and 55 infective juveniles per gram of manure and 5.1 and 104 infective juveniles per square centimeter of surface area. Infective juveniles capable of infecting greater wax moth larvae, Galleria mellonella (L.), survived in manure for up to 10 wk without hosts.

Response of Screwworms (Diptera: Calliphoridae) to Changes in the concentration of Blood, Egg, and Milk in the Larval Diet

David B. Taylor — Thu, 09 Feb 2012 15:16:02 PST

Larvae of screwworm, Cochliomyia hominivorax (Coquerel), were reared on diets with varying concentrations of whole dried bovine blood, whole dried egg, and nonfat dried milk. Pupal weight, egg to pupal survival, adult emergence, sex ratio, fecundity, and fertility were significantly affected by one or more of the dietary components. Curvilinear models for the effect of dietary component concentration on life history parameters were derived by multiple regression. Most models resulted in bell-shaped curves that were used to calculate optimal diet component concentrations. Biomass, survival, emergence, and fecundity were maximized at 6% blood, 5% egg, and 1.3% milk.