Many factors can negatively affect honey bee (Apis mellifera L.) health including the pervasive use of systemic neonicotinoid insecticides. Through direct consumption of contaminated nectar and pollen from treated plants, neonicotinoids can affect foraging, learning, and memory in worker bees. Less well studied are the potential effects of neonicotinoids on queen bees, which may be exposed indirectly through trophallaxis, or food-sharing. To assess effects on queen productivity, small colonies of different sizes (1500, 3000, and 7000 bees) were fed imidacloprid (0, 10, 20, 50, and 100 ppb) in syrup for three weeks. We found adverse effects of imidacloprid on queens (egg-laying and locomotor activity), worker bees (foraging and hygienic activities), and colony development (brood production and pollen stores) in all treated colonies. Some effects were less evident as colony size increased, suggesting that larger colony populations may act as a buffer to pesticide exposure. This study is the first to show adverse effects of imidacloprid on queen bee fecundity and behavior and improves our understanding of how neonicotinoids may impair short-term colony functioning. These data indicate that risk-mitigation efforts should focus on reducing neonicotinoid exposure in the early spring when colonies are smallest and queens are most vulnerable to exposure.

No abstract

There exist a variety of factors that negatively impact the health and survival of managed honey bee colonies, including the spread of parasites and pathogens, loss of habitat, reduced availability or quality of food resources, climate change, poor queen quality, changing cultural and commercial beekeeping practices, as well as exposure to agricultural and apicultural pesticides both in the field and in the hive. These factors are often closely intertwined, and it is unlikely that a single stressor is driving colony losses. There is a growing consensus, however, that increasing prevalence of parasites and pathogens are among the most significant threats to managed bee colonies. Unfortunately, improper management of hives by beekeepers may exacerbate parasite populations and disease transmission. Furthermore, research continues to accumulate that describes the complex and largely harmful interactions that exist between pesticide exposure and bee immunity. This brief review summarizes our progress in understanding the impact of pesticide exposure on bees at the individual, colony, and community level.

Neonicotinoids are highly toxic to insects and may systemically translocate to nectar and pollen of plants where foraging bees may become exposed. Exposure to neonicotinoids can induce detrimental sublethal effects on individual and colonies of bees and may have long-term impacts, such as impaired foraging, reduced longevity, and reduced brood care or production. Less well-studied are the potential effects on queen bumble bees that may become exposed while foraging in the spring during colony initiation. This study assessed queen survival and nest founding in caged bumble bees [Bombus impatiens (Cresson) (Hymenoptera: Apidae)] after chronic (18-d) dietary exposure of imidacloprid in syrup (1, 5, 10, and 25 ppb) and pollen (0.3, 1.7, 3.3, and 8.3 ppb), paired respectively. Here we show some mortality in queens exposed at all doses even as low as 1 ppb, and, compared with untreated queens, significantly reduced survival of treated queens at the two highest doses. Queens that survived initial imidacloprid exposure commenced nest initiation; however, they exhibited dose-dependent delay in egg-laying and emergence of worker brood. Furthermore, imidacloprid treatment affected other parameters such as nest and queen weight. This study is the first to show direct impacts of imidacloprid at field-relevant levels on individual B. impatiens queen survival and nest founding, indicating that bumble bee queens are particularly sensitive to neonicotinoids when directly exposed. This study also helps focus pesticide risk mitigation efforts and highlights the importance of reducing exposure rates in the early spring when bumble bee queens, and other wild bees are foraging and initiating nests.

Honey has been used as a nutrient, an ointment, and a medicine worldwide for many centuries. Modern research has demonstrated that honey has many medicinal properties, reflected in its anti‐microbial, anti‐oxidant, and anti‐inflammatory bioactivities. Honey is composed of sugars, water and a myriad of minor components, including minerals, vitamins, proteins and polyphenols. Here, we report a new bioactive component‒vesicle‐like nanoparticles‒in honey (H‐VLNs). These H‐VLNs are membrane‐bound nano‐scale particles that contain lipids, proteins and small‐sized RNAs. The presence of plant‐originated plasma transmembrane proteins and plasma membrane‐associated proteins suggests the potential vesicle‐like nature of these particles. H‐VLNs impede the formation and activation of the nucleotide‐binding domain and leucine‐rich repeat related (NLR) family, pyrin domain containing 3 (NLRP3) inflammasome, which is a crucial inflammatory signalling platform in the innate immune system. Intraperitoneal administration of H‐VLNs in mice alleviates inflammation and liver damage in the experimentally induced acute liver injury. miR‐4057 in H‐VLNs was identified in inhibiting NLRP3 inflammasome activation. Together, our studies have identified anti‐inflammatory VLNs as a new bioactive agent in honey.

Managed honey bees (Apis mellifera L.) and wild bees provide critical ecological services that shape and sustain natural, agricultural, and urban landscapes. In recent years, declines in bee populations have highlighted the importance of the pollination services they provide and the need for more research into the reasons for global bee losses. Several stressors cause declining populations of managed and wild bee species such as habitat degradation, pesticide exposure, and pathogens. Viruses, which have been implicated as a key stressor, are able to infect a wide range of species and can be transmitted both intra-and inter-specifically from infected bee species to uninfected bee species via vertical (from parent to offspring) and/or horizontal (between individuals via direct or indirect contact) transmission. To explore how viruses spread both intra-and inter-specifically within a community, we examined the impact of management, landscape type, and bee species on the transmission of four common viruses in Nebraska: Deformed wing virus (DWV), Israeli acute paralysis virus (IAPV), Black queen cell virus (BQCV), and Sacbrood virus (SBV). Results indicated the prevalence of viruses is significantly affected (P < 0.005) by bee species, virus type, and season, but not by landscape or year (P = 0.290 and 0.065 respectively). The higher prevalence of DWV detected across bee species (10.4% on Apis mellifera, 5.3% on Bombus impatiens, 6.1% on Bombus griseocollis, and 22.44% on Halictus ligatus) and seasons (10.8% in earlymid summer and 11.4% in late summer) may indicate a higher risk of interspecific transmission of DWV. However, IAPV was predominately detected in Halictus ligatus (20.7%) and in late season collections (28.1%), which may suggest species-specific susceptibility and seasonal trends in infection rates associated with different virus types. However, there were limited detections of SBV and BQCV in bees collected during both sampling periods, indicating SBV and BQCV may be less prevalent among bee communities in this area.

Background Lake Sinai Viruses (LSV) are common RNA viruses of honey bees (Apis mellifera) that frequently reach high abundance but are not linked to overt disease. LSVs are genetically heterogeneous and collectively widespread, but despite frequent detection in surveys, the ecological and geographic factors structuring their distribution in A. mellifera are not understood. Even less is known about their distribution in other species. Better understanding of LSV prevalence and ecology have been hampered by high sequence diversity within the LSV clade. Methods Here we report a new polymerase chain reaction (PCR) assay that is compatible with currently known lineages with minimal primer degeneracy, producing an expected 365 bp amplicon suitable for end-point PCR and metagenetic sequencing. Using the Illumina MiSeq platform, we performed pilot metagenetic assessments of three sample sets, each representing a distinct variable that might structure LSV diversity (geography, tissue, and species). Results The first sample set in our pilot assessment compared cDNA pools from managed A. mellifera hives in California (n = 8) and Maryland (n = 6) that had previously been evaluated for LSV2, confirming that the primers co-amplify divergent lineages in real-world samples. The second sample set included cDNA pools derived from different tissues (thorax vs. abdomen, n = 24 paired samples), collected from managed A. mellifera hives in North Dakota. End-point detection of LSV frequently differed between the two tissue types; LSV metagenetic composition was similar in one pair of sequenced samples but divergent in a second pair. Overall, LSV1 and intermediate lineages were common in these samples whereas variants clustering with LSV2 were rare. The third sample set included cDNA from individual pollinator specimens collected from diverse landscapes in the vicinity of Lincoln, Nebraska. We detected LSV in the bee Halictus ligatus (four of 63 specimens tested, 6.3%) at a similar rate as A. mellifera (nine of 115 specimens, 7.8%), but only one H. ligatus sequencing library yielded sufficient data for compositional analysis. Sequenced samples often contained multiple divergent LSV lineages, including individual specimens. While these studies were exploratory rather than statistically powerful tests of hypotheses, they illustrate the utility of high-throughput sequencing for understanding LSV transmission within and among species.

The 2020 American Bee Research Conference (ABRC) was held on 9–10 January 2020 in conjunction with the annual convention of the American Beekeeping Federation Conference and Trade Show in Schaumburg, IL. Over the two-day conference, a total of 65 oral and poster presentations were given, representing work done from over 30 different research groups from throughout the United States and Canada. These proceedings contain the submitted abstracts for presentations given at the 2020 American Bee Research Conference.