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Research Project: Quantifying and Reducing Colony Losses from Nutritional, Pathogen/Parasite, and Pesticide Stress by Improving Colony Management Practices

Location: Carl Hayden Bee Research Center

2022 Annual Report

1. Improving the management of honey bee colonies overwintered in cold storage. Every year more honey bee colonies are overwintered in cold storage to reduce losses that have averaged 40% during this time of year. However, beekeepers need to know when to put colonies in cold storage. They also need to know if colonies from different regions of the United States, especially the southern states, do equally well as colonies from temperate regions when overwintered in cold storage. ARS researchers in Tucson, Arizona, found that colonies summered in northern latitudes and put into cold storage by mid-October were larger and had more brood after cold storage and after almond pollination than those put into cold storage in November. They also found differences in physiological markers between bees from northern and southern latitudes suggesting that colonies that summer in southern latitudes do not convert into functional winter bees that can survive long periods of confinement in the hive. When overwintered in cold storage, colonies from southern latitudes were smaller and had lower survival rates after cold storage and almond bloom than those from northern latitudes.

2. Increasing our understanding of CO2 concentration in bee hive. The use of sensors in bee hives is increasing as a research tool to understand the relationship between bee colonies, their environment, and the effects of stressors and management practices. Carbon dioxide (CO2), a byproduct of respiration, is toxic at high concentrations, so controlling CO2 within the hive is an important colony function. To help understand factors that affect CO2 concentration, ARS researchers in Tucson, Arizona initiated an experiment where sensors measured CO2 at 15 second intervals for hives with screened and solid bottom boards. Although ventilation increased with screen bottom boards, average CO2 concentrations rose higher, rather than dropped, indicating that CO2 concentration was not simply a function of ventilation. Colony temperature and foraging activity were unaffected by the change in bottom boards. Although bee colonies have been reported to cycle air within the hive, with shorter periods of 20 to 150 seconds and longer periods of 42-80 minutes, researchers found no evidence of significant CO2 cycle periods other than a strong 24 hour period. Bee colonies in the study maintained average maximum concentrations greater than 11,000 parts per million, even with increased ventilation, indicating that the relationship of bee colonies to CO2 concentration is complex. Data on CO2 concentration may include information on colony health.

3. Increasing our knowledge of how colony nutrients change over time. Natural and supplemental diets that are available to hives throughout the year must meet the colony’s nutritional needs, as poor nutrition compromises colony health. ARS researchers in Tucson, Arizona, characterized the nutrients that are stored and utilized by the bee during key seasonal changes in the colony (Experiment 1). They concluded that macronutrients like total lipid and protein correlate with seasonal patterns of hive growth and contraction. This information allows researchers to address the secondary goal of this work, which is to determine whether existing supplements meet these seasonal nutrient needs (Experiment 2). Many of these focal nutrients (lipids, proteins, fatty acids) that are correlated with these seasonal colony changes are limited in commercial diets and the environment. Experiment 2 tests the hypothesis that diets containing a better balance of these limiting nutrients can be used during these seasonal transitions to maximize colony health. The researchers are designing custom diets with high or low levels of these focal nutrients for use in Experiment 2, which begins in late ficscal year 2022 to early fiscal year 2023.

4. Canola (Brassica sp.) pollen fatty acids vary genetically and do not correlate with seed fatty acids. ARS researchers in Tucson, Arizona, collected fatty acid data research data that indicates that pollen fatty acid content varies among canola cultivars. Interestingly, the genetic variation in pollen fatty acid content did not correlate to seed fatty acid content, suggesting that selection on seed traits is independent of selection for pollen fatty acids. Based on these observations, canola breeders can develop cultivars with desirable seed traits that also produce pollen that is nutritious for bees. Additionally, similar Brassica species are used in almond orchards prior to bloom as important early season forage for colonies. High nutrient Brassica species can be incorporated into the seed mixtures that are currently planted in this region to increase pre-bloom colony nutrition.

5. Sunflower (Helianthus annuus) pollen fatty acids vary genetically and do not correlate with seed fatty acids. ARS researchers in Tucson, Arizona, discovered that both essential and non-essential fatty acids in pollen varied among commercial and wild type sunflower cultivars. Their research results showed that pollen fatty acid contents did not correlate with seed oil fatty acid contents, suggesting that intensive agronomic selection for seed oil fatty acids is independent of pollen fatty acid contents. As well, pollen fatty acid contents of the same cultivars, by and large, differed between field locations (Arizona and North Dakota), indicating that environmental conditions impact pollen fatty acid contents. This independence of seed and pollen fatty acid contents opens the possibility of selecting sunflower cultivars with nutritious pollen contents, likely dependent on local environmental conditions, that will be beneficial to bees without disrupting seed oil production for humans.

Review Publications
Meikle, W.G., Colin, T., Adamczyk Jr., J.J., Weiss, M., Barron, A. 2022. Traces of a neonicotinoid pesticide stimulate different honey bee colony activities, but do not increase colony size or longevity. Ecotoxicology and Environmental Safety. 231. Article 113202.
Kulyukin, V., Tkachenko, A., Price, K., Meikle, W.G., Weiss, M. 2022. Integration of scales and cameras in nondisruptive electronic beehive monitoring: On the within-day relationship of hive weight and traffic in honeybee (Apis mellifera) colonies in Langstroth hives in Tucson, Arizona, USA. Sensors. 22(13). Article 4824.
Garber, K., Hoffman, G.D., Curry, R., Minucci, J., Dawson, D.E., Douglass, C., Milone, J., Purucker, S.T. 2022. Simulating the effects of pesticides on honey bee (Apis mellifera L.) colonies with BeePop+. Ecologies. 3(3):275-291.
Desjardins, N., Fisher, A., Ozturk, C., Fewell, J., Hoffman, G.D., Harrison, J., Smith, B. 2021. A common fungicide, Pristine®, impairs olfactory associative learning performance in honey bees (Apis mellifera). Environmental Pollution. 288. Article 117720.
He, N., Zhang, Y., Duan, X., Li, J., Huang, W., Evans, J.D., Hoffman, G.D., Chen, Y., Huang, S. 2022. RNA interference-mediated knockdown of genes encoding spore wall proteins confers protection against Nosema ceranae infection in the European Honey Bee, Apis mellifera. Microorganisms. 9(3):505.
Minucci, J.M., Curry, R., Hoffman, G.D., Douglass, C., Garber, K., Purucker, T.S. 2021. Inferring pesticide toxicity to honey bees from a field-based feeding study using a colony model and Bayesian inference. Ecological Applications. 31(8). Article e02442.
Messan, K., Rodriguez Messan, M., Chen, J., Hoffman, G.D., Kang, Y. 2020. Population dynamics of Varroa mite and honeybee: Effects of parasitism with age structure and seasonality. Ecological Modelling. 440. Article 109359.
Carroll, M.J., Corby-Harris, V.L., Brown, N.J., Snyder, L.A., Reitz, D.C. 2022. Methoxyfenozide has minimal effects on replacement queens but may negatively affect sperm storage. Apidologie. 53. Article 33.
Meikle, W.G., Barg, A., Weiss, M. 2022. Honey bees colonies maintain CO2 temperature regimes in spite of change in hive characteristics. Apidologie. 53. Article 51.
Fisher, A., Cogley, T., Ozturk, C., Hoffman, G.D., Smith, B., Kaftanoglu, O., Fewell, J., Harrison, J. 2021. The active ingredients of a mitotoxic fungicide negatively affect pollen consumption and worker survival in laboratory-reared honey bees (Apis mellifera). Ecotoxicology and Environmental Safety. 226. Article 112841.
Chen, Y., Hoffman, G.D., Ratti, V., Kang, Y. 2021. Review on mathematical modeling of honeybee population dynamics. Mathematical Biosciences and Engineering (MBE) Journal. 18(6):9606-9650.