Landscape-scale floral resource discontinuity decreases bumble bee occurrence and alters community composition.

Agricultural practices and intensification during the past two centuries have dramatically altered the abundance and temporal continuity of floral resources that support pollinating insects such as bumble bees. Long-term trends among bumble bees within agricultural regions suggest that intensive agricultural conditions have created inhospitable conditions for some species, while other species have maintained their relative abundances despite landscape-level changes in flower availability. Bumble bee responses to spatiotemporal resource heterogeneity have been explored at the colony and behavioral level, but we have yet to understand whether these conditions drive community structure and ultimately explain the diverging patterns in long-term species trends. To explore the relationship between landscape-level floral resource continuity and the likelihood of bumble bee occurrence, we mapped the relative spatial and temporal availability of floral resources within an intensive agricultural region in the US Upper Midwest and related this resource availability with bumble bee species relative abundance. Across the bee community, we found that relative bumble bee occurrence increases in landscapes containing more abundant and more temporally continuous floral resources. Declining species, such as Bombus terricola, exhibited the strongest, positive responses to resource abundance and continuity whereas common, stable species, such as Bombus impatiens, showed no statistical relationship to either. Together with existing experimental evidence, this work suggests that efforts to increase spatiotemporal flower availability, along with overall flower abundance at landscape scales may have positive effects on bumble bee communities in the US Upper Midwest.

Predictors of E-cigarette and Cigarette Use Trajectory Classes from Early Adolescence to Emerging Adulthood Across Four Years (2013-2017) of the PATH Study.

INTRODUCTION: This study examines predictors of trajectories of cigarette and e-cigarette use among a cohort of US adolescents transitioning into young adulthood. Comparing trajectories of each tobacco product is important to determine if different intervention targets are needed to prevent progression to daily use. METHODS: Latent trajectory class analyses identified cigarette and e-cigarette use (never, ever excluding past 12-month, past 12-month (excluding past 30-day (P30D)), P30D 1-5 days, P30D 6+ days) trajectory classes, separately, among US youth (12-17; N = 10,086) using the first 4 waves (2013-2017) of data from the nationally representative PATH Study. Weighted descriptive analyses described the class characteristics. Weighted multinomial logistic regression analyses examined demographic, psychosocial, and behavioral predictors of class membership. RESULTS: Younger adolescents 12-15 years had lower tobacco use compared to 16-17 year olds and less stable classes. In the 16-17 year group, there were five unique trajectories of cigarette smoking, including a Persistent High Frequency class. Four e-cigarette use trajectories were identified; but not a persistent use class. Shared predictors of class membership for cigarettes and e-cigarettes included mental health problems, other tobacco use, marijuana use, and poorer academic achievement. Male sex and household tobacco use were unique e-cigarette trajectory class predictors. CONCLUSIONS: There was no evidence that initiation with e-cigarettes as the first product tried was associated with cigarette progression (nor cigarettes as first product and e-cigarette progression). Interventions should focus on well-established risk factors such as mental health and other substance use to prevent progression of use for both tobacco products. IMPLICATIONS: Using nationally representative data and definitions of use that take into account frequency and recency of use, longitudinal 4-year trajectories of e-cigarette and cigarette use among US adolescents transitioning into young adulthood were identified. Results among 16-17-year olds revealed a class of persistent high frequency cigarette smoking that was not identified for e-cigarette use. Cigarette use progression was not associated with e-cigarettes as the first product tried. Risk factors for progression of use of both products included mental health and other substance use, which are important prevention targets for both tobacco products.

Transitions to smokeless tobacco use among adult cigarette smokers in the Population Assessment of Tobacco and Health (PATH) Study, Waves 3-5 (2015-2019).

OBJECTIVE: Examine patterns of dual use of cigarettes and smokeless tobacco and complete switching over time among adult current cigarette smokers using data from the Population Assessment of Tobacco and Health Study Wave 3 (2015-2016), Wave 4 (2016-2018) and Wave 5 (2018-2019). METHODS: We examined four tobacco use states among 6834 exclusive smokers and 372 dual users at Wave 3 with two waves of follow-up data: exclusive cigarette use, exclusive smokeless tobacco use, dual use and use of neither product. RESULTS: Among exclusive smokers at Wave 3, only 1.6% (95% CI: 1.3% to 2.1%) transitioned to dual use at Wave 4, and 0.1% (95% CI: 0.07% to 0.2%) switched to exclusive smokeless tobacco use. Among exclusive smokers who switched to dual use, 53.1% (95% CI: 40.9% to 64.9%) returned to exclusive cigarette smoking, 34.3% (95% CI: 23.8% to 46.6%) maintained dual use and 12.6% (95% CI: 7.0% to 21.7%) did not smoke cigarettes after an additional wave of follow-up. Dual users at Wave 3 were likely to maintain their dual use status at Wave 4, 51.2% (95% CI: 46.1% to 56.3%) and Wave 5, 47.9% (95% CI: 40.1% to 55.8%). CONCLUSIONS: Very few cigarette smokers transition to smokeless tobacco use, and among those who do, dual use is more common than exclusive smokeless tobacco use. Further, the majority of exclusive cigarette smokers who transition to dual use at Wave 4 continue smoking cigarettes at Wave 5, either as dual users or as exclusive smokers.

Omnivory in Bees: Elevated Trophic Positions among All Major Bee Families.

As pollen and nectar foragers, bees have long been considered strictly herbivorous. Their pollen provisions, however, are host to abundant microbial communities, which feed on the pollen before and/or while it is consumed by bee larvae. In the process, microbes convert pollen into a complex of plant and microbial components. Since microbes are analogous to metazoan consumers within trophic hierarchies, the pollen-eating microbes are, functionally, herbivores. When bee larvae consume a microbe-rich pollen complex, they ingest proteins from plant and microbial sources and thus should register as omnivores on the trophic "ladder." We tested this hypothesis by examining the isotopic compositions of amino acids extracted from native bees collected in North America over multiple years. We measured bee trophic position across the six major bee families. Our findings indicate that bee trophic identity was consistently and significantly higher than that of strict herbivores, providing the first evidence that omnivory is ubiquitous among bee fauna. Such omnivory suggests that pollen-borne microbes represent an important protein source for larval bees, which introduces new questions as to the link between floral fungicide residues and bee development.

Microbes are trophic analogs of animals.

In most ecosystems, microbes are the dominant consumers, commandeering much of the heterotrophic biomass circulating through food webs. Characterizing functional diversity within the microbiome, therefore, is critical to understanding ecosystem functioning, particularly in an era of global biodiversity loss. Using isotopic fingerprinting, we investigated the trophic positions of a broad diversity of heterotrophic organisms. Specifically, we examined the naturally occurring stable isotopes of nitrogen ((15)N:(14)N) within amino acids extracted from proteobacteria, actinomycetes, ascomycetes, and basidiomycetes, as well as from vertebrate and invertebrate macrofauna (crustaceans, fish, insects, and mammals). Here, we report that patterns of intertrophic (15)N-discrimination were remarkably similar among bacteria, fungi, and animals, which permitted unambiguous measurement of consumer trophic position, independent of phylogeny or ecosystem type. The observed similarities among bacterial, fungal, and animal consumers suggest that within a trophic hierarchy, microbiota are equivalent to, and can be interdigitated with, macrobiota. To further test the universality of this finding, we examined Neotropical fungus gardens, communities in which bacteria, fungi, and animals are entwined in an ancient, quadripartite symbiosis. We reveal that this symbiosis is a discrete four-level food chain, wherein bacteria function as the apex carnivores, animals and fungi are meso-consumers, and the sole herbivores are fungi. Together, our findings demonstrate that bacteria, fungi, and animals can be integrated within a food chain, effectively uniting the macro- and microbiome in food web ecology and facilitating greater inclusion of the microbiome in studies of functional diversity.

A global synthesis of the effects of diversified farming systems on arthropod diversity within fields and across agricultural landscapes.

Agricultural intensification is a leading cause of global biodiversity loss, which can reduce the provisioning of ecosystem services in managed ecosystems. Organic farming and plant diversification are farm management schemes that may mitigate potential ecological harm by increasing species richness and boosting related ecosystem services to agroecosystems. What remains unclear is the extent to which farm management schemes affect biodiversity components other than species richness, and whether impacts differ across spatial scales and landscape contexts. Using a global metadataset, we quantified the effects of organic farming and plant diversification on abundance, local diversity (communities within fields), and regional diversity (communities across fields) of arthropod pollinators, predators, herbivores, and detritivores. Both organic farming and higher in-field plant diversity enhanced arthropod abundance, particularly for rare taxa. This resulted in increased richness but decreased evenness. While these responses were stronger at local relative to regional scales, richness and abundance increased at both scales, and richness on farms embedded in complex relative to simple landscapes. Overall, both organic farming and in-field plant diversification exerted the strongest effects on pollinators and predators, suggesting these management schemes can facilitate ecosystem service providers without augmenting herbivore (pest) populations. Our results suggest that organic farming and plant diversification promote diverse arthropod metacommunities that may provide temporal and spatial stability of ecosystem service provisioning. Conserving diverse plant and arthropod communities in farming systems therefore requires sustainable practices that operate both within fields and across landscapes.

Patterns of Use of Smokeless Tobacco in US Adults, 2013-2014.

OBJECTIVES: To examine patterns of smokeless tobacco (SLT) use, by type, in wave 1 (2013-2014) of the Population Assessment of Tobacco and Health Study in the United States. METHODS: We analyzed data from 32 320 adults (aged ≥ 18 years) to assess the use of pouched snus and other SLT products (loose snus, moist snuff, dip, spit, and chewing tobacco). RESULTS: Overall, SLT use was most common among men, younger adults, non-Hispanic Whites, and nonurban respondents. Pouched snus users were more likely to report nondaily and polytobacco use than users of other SLT products. Respondents who used SLT some days were more likely to be current established cigarette smokers than those who used SLT every day (57.9% vs 20.2%). Furthermore, current established smokers who used SLT some days were more likely to smoke every day and had a higher median number of cigarettes smoked per day than smokers who used SLT every day. CONCLUSIONS: Polytobacco use, especially cigarette smoking, is common among SLT users. Pouched snus users are more likely to report nondaily snus use and polytobacco use than users of other SLT products.

Tobacco Product Use Among Adults - United States, 2013-2014.

While significant declines in cigarette smoking have occurred among U.S. adults during the past 5 decades, the use of emerging tobacco products* has increased in recent years (1-3). To estimate tobacco use among U.S. adults aged ≥18 years, CDC and the Food and Drug Administration (FDA) analyzed data from the 2013-2014 National Adult Tobacco Survey (NATS). During 2013-2014, 21.3% of U.S. adults used a tobacco product every day or some days, and 25.5% of U.S. adults used a tobacco product every day, some days, or rarely. Despite progress in reducing cigarette smoking, during 2013-2014, cigarettes remained the most commonly used tobacco product among adults. Young adults aged 18-24 years reported the highest prevalence of use of emerging tobacco products, including water pipes/hookahs and electronic cigarettes (e-cigarettes). Furthermore, racial/ethnic and sociodemographic differences in the use of any tobacco product were observed, with higher use reported among males; non-Hispanic whites, non-Hispanic blacks, and non-Hispanics of other races(†); persons aged <45 years; persons living in the Midwest or South; persons with a General Educational Development (GED) certificate; persons who were single/never married/not living with a partner or divorced/separated/widowed; persons with annual household income <$20,000; and persons who were lesbian, gay, or bisexual (LGB). Population-level interventions that focus on all forms of tobacco product use, including tobacco price increases, high-impact anti-tobacco mass media campaigns, comprehensive smoke-free laws, and enhanced access to help quitting tobacco use, in conjunction with FDA regulation of tobacco products, are critical to reducing tobacco-related diseases and deaths in the United States.(§).

Frequency of Adverse Events Before, During, and After Hospital Admission.

OBJECTIVES: Adverse events (AEs) are unintended physical injuries resulting from or contributed to by medical or surgical care. We determined the frequency and type of AEs before, during, and after hospital admission. METHODS: We conducted a cohort study of 296 adult hospital patients. We used the standardized Institute for Healthcare Improvement Global Trigger Tool for Measuring Adverse Events to review the medical records of the hospital patients for occurrence, timing relative to hospital admission, severity, and preventability of AEs. We also identified the primary physiologic system affected by the AE. RESULTS: Among 296 patients, we identified 338 AEs. AEs occurred with similar frequency before (n = 148; 43.8%) and during hospital admission (n = 162; 47.9%). Fewer AEs occurred after discharge (n = 28; 8.3%). Half of all AEs (n = 169; 50.0%) were severe, whereas 47.9% (n = 162) were preventable. CONCLUSIONS: AEs occur with similar frequency before and during hospitalization and may contribute more to hospital admissions than previously recognized. These findings suggest that efforts to improve patient safety should include outpatient settings in addition to the more commonly targeted acute care settings.

A systematic review of transitions between cigarette and smokeless tobacco product use in the United States.

BACKGROUND: Smokeless tobacco use is becoming an increasingly important public health issue in the US and may influence cigarette smoking behavior. Systematic information on transitions between smokeless tobacco and cigarette use in the US is limited. METHODS: We conducted a systematic review of published literature on transitions between smokeless tobacco and cigarette use in the US. We searched PubMed, Web of Science and EbscoHost databases for all published articles from January 2000 to March 2014 that presented estimates of transitions in US youth and adult study populations over time between at least one of the following tobacco use states: exclusive cigarette smoking, exclusive smokeless tobacco use, dual use of both products, and use of neither product. We excluded non-English language studies, studies published before 2000, clinical trials, controlled cessation programs, and clinical studies or evaluations of smokeless tobacco cessation programs. RESULTS: The review identified six studies on US populations published since 2000 with longitudinal data on some or all of the transitions that users can undergo between smokeless tobacco and cigarette use. There was considerable heterogeneity across studies in design and tobacco use definitions. Despite these differences, the existing data indicate that switching behaviors from exclusive smoking to exclusive smokeless tobacco use are limited (adults: 0%-1.4%, adolescents: 0.8%-3.8%) but may be more common from exclusive smokeless tobacco use to exclusive smoking (adults: 0.9%-26.6%, adolescents: 16.6%-25.5%). Among adults, exclusive cigarette smoking was generally stable and consistent (79.7% to 87.6%) over follow-up across studies but less stable in adolescents (46.8%-78.7%). Exclusive smokeless tobacco use was less stable than exclusive cigarette smoking over time (adults: 59.4%-76.6%, adolescents: 26.2%-44.8%). CONCLUSION: This review provides published estimates of the proportions of adults and adolescents transitioning between tobacco use categories from the most recently available studies on longitudinal transitions between smokeless tobacco and cigarettes in the US. These data can be used to track tobacco use behaviors and evaluate their effect on public health; however, the data for these studies were generally collected more than a decade ago. Additional research including nationally representative longitudinal estimates using consistent definitions and designs, would improve understanding of current tobacco transition behaviors.

Linkage of 1986-2009 National Health Interview Survey with 1981-2010 Florida Cancer Data System.

BACKGROUND: National survey data linked with state cancer registry data has the potential to create a valuable tool for cancer prevention and control research. A pilot project-developed in a collaboration of the Centers for Disease Control and Prevention's National Center for Health Statistics (NCHS) and the Florida Cancer Data System (FCDS) at the University of Miami -links the records of the 1986-2009 National Health Interview Survey (NHIS) and the 1981-2010 FCDS. The project assesses the feasibility of performing a record linkage between NCHS survey data and a state-based cancer registry, as well as the value of the data produced. The linked NHIS-FCDS data allow researchers to follow NHIS survey participants longitudinally to examine factors associated with future cancer diagnosis, and to assess the characteristics and quality of life among cancer survivors. METHODS: This report provides a preliminary evaluation of the linked national and state cancer data and examines both analytic issues and complications presented by the linkage. CONCLUSIONS: Residential mobility and the number of years of data linked in this project create some analytic challenges and limitations for the types of analyses that can be conducted. However, the linked data set offers the ability to conduct analyses not possible with either data set alone.

Tobacco product use among adults--United States, 2012-2013.

Despite significant declines in cigarette smoking among U.S. adults over the past five decades, progress has slowed in recent years, and the prevalence of use of other tobacco products such as cigars and smokeless tobacco has not changed. Additionally, the prevalence of use of emerging products, including electronic cigarettes (e-cigarettes), has rapidly increased. This report provides the most recent national estimates of tobacco use among adults aged ≥18 years, using data from the 2012-2013 National Adult Tobacco Survey (NATS). The findings indicate that 21.3% of U.S. adults used a tobacco product every day or some days, and 25.2% used a tobacco product every day, some days, or rarely. Population-level interventions focused on the diversity of tobacco product use, including tobacco price increases, high-impact antitobacco mass media campaigns, comprehensive smoke-free laws, and enhanced access to help quitting, in conjunction with Food and Drug Administration (FDA) regulation of tobacco products, are critical to reducing tobacco-related diseases and deaths in the United States.

Correlates of tobacco product initiation among youth and young adults between waves 1-4 of the population assessment of tobacco and Health (PATH) study (2013-2018).

INTRODUCTION: While risk factors for cigarette smoking among youth and young adults are well-documented, less is known about the correlates of initiation of other tobacco products. This study aims to provide estimates and correlates of initiation among U.S. youth and young adults. METHODS: Data on youth aged 12-17 (n = 10,072) and young adults aged 18-24 (N = 5,727) who provided information on cigarettes, electronic nicotine delivery systems (ENDS), cigars, pipe, hookah and smokeless tobacco use in Wave 1 (W1: 2013-2014)-Wave 4 (W4: 2016-2018) of the nationally-representative PATH Study were used to calculate ever use initiation and correlates of initiation by W4. RESULTS: Nearly 6 million youth and 2.5 million young adults used tobacco for the first time between W1-W4. Approximately one quarter of youth and young adult ENDS never users initiated ENDS between W1-W4 of the PATH Study. Among youth, use of other tobacco products, ever substance use, and high externalizing problems were associated with initiation of most products. Among young adults, use of other tobacco products and ever substance use were associated with initiation of most products. In both youth and young adults, Hispanics were more likely to initiate hookah use than their non-Hispanic White counterparts. While male sex was a risk factor for most tobacco product initiation across both age groups, it was not associated with hookah initiation. CONCLUSIONS: Cigarette and non-cigarette products shared many correlates of initiation, although there are noteworthy demographic differences. Findings can help tailor product specific interventions to reach populations at risk during preliminary stages of use.

Young Egyptians' perceptions, attitudes and knowledge of injuries.

The objective of this study was to qualitatively evaluate young Egyptians' perceptions, attitudes, knowledge and behaviour towards injuries before implementation of an extensive questionnaire about injuries among Egyptian youth. In 2008, five focus groups of three to nine participants each were conducted in Cairo, Egypt in Arabic to evaluate young Egyptians' attitudes towards injuries, injury prevention, and their understanding of 'accidents' and fatalism. Participants were 14-26 years of age and were from medium to high socioeconomic status. Focus group participants noted that the concept of hadthah ('accident') signified an event determined by destiny, whereas esabah ('injury') was the result of human actions. The results of these focus groups indicate that young, educated Egyptians are interested in injury prevention programmes despite low confidence in the preventability of injuries.

Associations of risk factors of e-cigarette and cigarette use and susceptibility to use among baseline PATH study youth participants (2013-2014).

INTRODUCTION: Improved understanding of the distribution of traditional risk factors of cigarette smoking among youth who have ever used or are susceptible to e-cigarettes and cigarettes will inform future longitudinal studies examining transitions in use. METHODS: Multiple logistic regression analysis was conducted using data from youth (ages 12-17 years) who had ever heard of e-cigarettes at baseline of the PATH Study (n = 12,460) to compare the distribution of risk factors for cigarette smoking among seven mutually exclusive groups based on ever cigarette/e-cigarette use and susceptibility status. RESULTS: Compared to committed never users, youth susceptible to e-cigarettes, cigarettes, or both had increasing odds of risk factors for cigarette smoking, with those susceptible to both products at highest risk, followed by cigarettes and e-cigarettes. Compared to e-cigarette only users, dual users had higher odds of nearly all risk factors (aOR range = 1.6-6.8) and cigarette only smokers had higher odds of other (non-e-cigarette) tobacco use (aOR range = 1.5-2.3), marijuana use (aOR = 1.9, 95%CI = 1.4-2.5), a high GAIN substance use score (aOR = 1.9, 95%CI = 1.1-3.4), low academic achievement (aOR range = 1.6-3.4), and exposure to smoking (aOR range = 1.8-2.1). No differences were observed for externalizing factors (depression, anxiety, etc.), sensation seeking, or household use of non-cigarette tobacco. CONCLUSIONS: Among ever cigarette and e-cigarette users, dual users had higher odds of reporting traditional risk factors for smoking, followed by single product cigarette smokers and e-cigarette users. Understanding how e-cigarette and cigarette users differ may inform youth tobacco use prevention efforts and advise future studies assessing probability of progression of cigarette and e-cigarette use.

Point of Sale Scanner Data for Rapid Surveillance of the E-cigarette Market.

OBJECTIVES: Describe e-cigarette sales trends and market share from U.S. convenience stores and mass market retailers. METHODS: We used Nielsen Scantrack to calculate U.S. e-cigarette sales market share from convenience and mass market channels during the 4-week period ending 1/19/13 through the period ending 12/19/15. Internet searches were used to supplement Nielsen product information. RESULTS: From 2013 to 2015, rechargeable e-cigarette brands VUSE and MarkTen experienced the largest growth in Nielsen channels. E-liquid and tank type brands Vapin Plus and Haus experienced growth although their Nielsen market share is small compared to other brands. Sales of brands with high labeled nicotine content (according to packaging or website) increased. Fruit-flavored sales increased rapidly in Nielsen, yet still represent a minority of market share in these channels. DISCUSSION: Market-leading e-cigarette brands changed substantially in Nielsen channels from 2013 to 2015. Brand leaders in these channels are now owned by tobacco companies. Changes in labelled nicotine content and fruit-flavored products and product types suggest that as e-cigarette use increases, convenience store and mass market channels are offering new products to meet consumer preferences; however, Nielsen channels do not represent the entire e-cigarette marketplace.

Understanding Barriers to Participation in Cost-Share Programs For Pollinator Conservation by Wisconsin (USA) Cranberry Growers.

The expansion of modern agriculture has led to the loss and fragmentation of natural habitat, resulting in a global decline in biodiversity, including bees. In many countries, farmers can participate in cost-share programs to create natural habitat on their farms for the conservation of beneficial insects, such as bees. Despite their dependence on bee pollinators and the demonstrated commitment to environmental stewardship, participation in such programs by Wisconsin cranberry growers has been low. The objective of this study was to understand the barriers that prevent participation by Wisconsin cranberry growers in cost-share programs for on-farm conservation of native bees. We conducted a survey of cranberry growers (n = 250) regarding farming practices, pollinators, and conservation. Although only 10% of growers were aware of federal pollinator cost-share programs, one third of them were managing habitat for pollinators without federal aid. Once informed of the programs, 50% of growers expressed interest in participating. Fifty-seven percent of growers manage habitat for other wildlife, although none receive cost-share funding to do so. Participation in cost-share programs could benefit from outreach activities that promote the programs, a reduction of bureaucratic hurdles to participate, and technical support for growers on how to manage habitat for wild bees.

Do managed bees have negative effects on wild bees?: A systematic review of the literature.

Managed bees are critical for crop pollination worldwide. As the demand for pollinator-dependent crops increases, so does the use of managed bees. Concern has arisen that managed bees may have unintended negative impacts on native wild bees, which are important pollinators in both agricultural and natural ecosystems. The goal of this study was to synthesize the literature documenting the effects of managed honey bees and bumble bees on wild bees in three areas: (1) competition for floral and nesting resources, (2) indirect effects via changes in plant communities, including the spread of exotic plants and decline of native plants, and (3) transmission of pathogens. The majority of reviewed studies reported negative effects of managed bees, but trends differed across topical areas. Of studies examining competition, results were highly variable with 53% reporting negative effects on wild bees, while 28% reported no effects and 19% reported mixed effects (varying with the bee species or variables examined). Equal numbers of studies examining plant communities reported positive (36%) and negative (36%) effects, with the remainder reporting no or mixed effects. Finally, the majority of studies on pathogen transmission (70%) reported potential negative effects of managed bees on wild bees. However, most studies across all topical areas documented the potential for impact (e.g. reporting the occurrence of competition or pathogens), but did not measure direct effects on wild bee fitness, abundance, or diversity. Furthermore, we found that results varied depending on whether managed bees were in their native or non-native range; managed bees within their native range had lesser competitive effects, but potentially greater effects on wild bees via pathogen transmission. We conclude that while this field has expanded considerably in recent decades, additional research measuring direct, long-term, and population-level effects of managed bees is needed to understand their potential impact on wild bees.

Colonies of Bumble Bees (Bombus impatiens) Produce Fewer Workers, Less Bee Biomass, and Have Smaller Mother Queens Following Fungicide Exposure.

Bees provide vital pollination services to the majority of flowering plants in both natural and agricultural systems. Unfortunately, both native and managed bee populations are experiencing declines, threatening the persistence of these plants and crops. Agricultural chemicals are one possible culprit contributing to bee declines. Even fungicides, generally considered safe for bees, have been shown to disrupt honey bee development and impair bumble bee behavior. Little is known, however, how fungicides may affect bumble bee colony growth. We conducted a controlled cage study to determine the effects of fungicide exposure on colonies of a native bumble bee species (Bombus impatiens). Colonies of B. impatiens were exposed to flowers treated with field-relevant levels of the fungicide chlorothalonil over the course of one month. Colony success was assessed by the number and biomass of larvae, pupae, and adult bumble bees. Bumble bee colonies exposed to fungicide produced fewer workers, lower total bee biomass, and had lighter mother queens than control colonies. Our results suggest that fungicides negatively affect the colony success of a native bumble bee species and that the use of fungicides during bloom has the potential to severely impact the success of native bumble bee populations foraging in agroecosystems.