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More about the bees? We’re still doing this?

21 Mar 2022


“Saving the bees” is a tall order. The humble honeybee is a critical pollinator that helps maintain ecological balance in the face of agriculture. In 2009, the economic contribution of pollinators was valued at $153 billion (USD), or 9.5% of the agricultural economy 1. At this point, it is hard to find anyone that isn’t well aware of the decline of native bee populations and the consequences we can face as a result. While humans have certainly contributed to the decline of bee populations, a more optimistic perspective is that humans are also responsible for significant efforts to protect the bees by raising colonies, regulating pesticides and pollutants, and funding research aimed at stabilizing populations.

Bees have been on Restek’s radar for quite some time such as "Have You Heard the Buzz? Neonicotinoid Insecticides Increase Crop Yield, but Can Affect Our Bees!". The United States’ Environmental Protection Agency is poised to extend usage of neonicotinoids imidacloprid, thiamethoxam, clothianidin, and dinotefuran, despite concerns for the bees. While we can continue to hope that crop breeding and disease-resistance programs will reduce pesticide usage worldwide, for now, pesticides are a necessary evil. In turn, accurate monitoring of unintended exposure is critical in justifying the continued usage of neonicotinoids, as is being proposed. How else will we know when the consequences finally outweigh the benefits?

Following announcements that neonicotinoid usage was due for review in the United States, public comments on the proposed neonicotinoid expansion overwhelming favored the bees. To better understand how the United States’ actions compare worldwide, we can turn to Sciex’s 2019 blog which glimpsed trends in worldwide neonicotinoid usage. The European Union was the first to set strict bans and restrictions on neonicotinoid usage, and there has been increased interest in neonicotinoids’ environmental effects in Africa. However, Oceania, Canada, and the United States have been reluctant to ban usage, and instead have applied regulations and restrictions aimed at minimizing long-term consequences. There was little information available on regulations in Asia, South America, and Latin America. Regulated or not, neonicotinoids have been found in honey worldwide 5,9.

Bees collect pollen from a wide variety of plants in agriculture systems, inevitably encountering an equally wide variety of pesticides. In addition to being prolific pollinators, bees are valuable indicators of pesticide exposure in the environment as a whole, helping researchers quickly identify other local species at risk 4. As insects, bees are most vulnerable to poisoning from insecticides intended to target pests like aphids, stinkbugs, and mites. Well established lethal doses of insecticides help policymakers develop regulations aimed at keeping pollinators safe. However, continuing research demonstrates that exposure to fungicides and herbicides contribute to colony diseases and disruptions as well 5. Furthermore, the consequences of cumulative/additive sub-lethal exposures to multiple pesticides are becoming clearer by the day 5–7.

Recent surveys show that bees are not regularly exposed to lethal (>LD50) doses of any one pesticide, but instead may be suffering from cumulative sub-lethal doses of multiple pesticides 5–7. This has created a push for the development of analytical methods capable of quantifying low-level pesticide loads in bees and related products like pollen and honey. Many believe this means liquid chromatography will take the lead on pesticide analyses in honeybee applications 2,3,8, but research is still underway to find the ‘holy grail’ of methods that will be sensitive across a wide variety of pesticides.

In addition to sensitivity, clean-up methods need to be able to selectively extract pesticides from a variety of matrices. Pesticides may accumulate in the bee’s body, pollen, or honey 6,8. Hrynko et al. provides a great breakdown of analytical methods used for analyzing different groups of pesticides. QuEChERS-based methods provide versatility that many think will be crucial to monitoring pesticides in bees and related products 2,3,8. Bargańska et al. also suggests multi-stage methods which may be more adaptable to fluctuating pesticide usage 3As disease dynamics in crops change, pesticide usage is expected to continue to change as well, highlighting the need for versatile, ‘future-proof’, methods that can accurately monitor exposure to bee populations.

Chromatographers everywhere should be excited about advancements in sample clean-up and chromatography techniques aimed at improving detection and quantification of sub-lethal pesticide residues in bees and bee-products. Chromatography is a powerful tool that can keep policymakers informed about pesticide exposure in bees and local environments.

Tell us your stories in the comments and let us know: What can we do to help you save the bees?

Further reading:

  1. Gallai, N.; Salles, J.-M.; Settele, J.; Vaissière, B. E. Economic Valuation of the Vulnerability of World Agriculture Confronted with Pollinator Decline. Ecol. Econ. 200968 (3), 810–821.
  2. Hrynko, I.; Kaczyński, P.; Łozowicka, B. A Global Study of Pesticides in Bees: QuEChERS as a Sample Preparation Methodology for Their Analysis – Critical Review and Perspective. Sci. Total Environ. 2021792, 148385.
  3. Bargańska, Ż.; Lambropoulou, D.; Namieśnik, J. Problems and Challenges to Determine Pesticide Residues in Bumblebees. Crit. Rev. Anal. Chem. 201848 (6), 447–458.
  4. Cunningham, M. M.; Tran, L.; McKee, C. G.; Ortega Polo, R.; Newman, T.; Lansing, L.; Griffiths, J. S.; Bilodeau, G. J.; Rott, M.; Marta Guarna, M. Honey Bees as Biomonitors of Environmental Contaminants, Pathogens, and Climate Change. Ecol. Indic. 2022134, 108457.
  5. Traynor, K. S.; Tosi, S.; Rennich, K.; Steinhauer, N.; Forsgren, E.; Rose, R.; Kunkel, G.; Madella, S.; Lopez, D.; Eversole, H.; Fahey, R.; Pettis, J.; Evans, J. D.; Dennis vanEngelsdorp. Pesticides in Honey Bee Colonies: Establishing a Baseline for Real World Exposure over Seven Years in the USA. Environ. Pollut. 2021279, 116566.
  6. Pal, E.; Almasri, H.; Paris, L.; Diogon, M.; Pioz, M.; Cousin, M.; Sené, D.; Tchamitchian, S.; Tavares, D. A.; Delbac, F.; Blot, N.; Brunet, J.-L.; Belzunces, L. P. Toxicity of the Pesticides Imidacloprid, Difenoconazole and Glyphosate Alone and in Binary and Ternary Mixtures to Winter Honey Bees: Effects on Survival and Antioxidative Defenses. Toxics 202210 (3), 104.
  7. Ostiguy, N.; Drummond, F. A.; Aronstein, K.; Eitzer, B.; Ellis, J. D.; Spivak, M.; Sheppard, W. S. Honey Bee Exposure to Pesticides: A Four-Year Nationwide Study. Insects 201910 (1), 13.
  8. Tu, X.; Chen, W. Overview of Analytical Methods for the Determination of Neonicotinoid Pesticides in Honeybee Products and Honeybee. Crit. Rev. Anal. Chem. 202151 (4), 329–338.
  9. Mitchell, E. A. D.; Mulhauser, B.; Mulot, M.; Mutabazi, A.; Glauser, G.; Aebi, A. A Worldwide Survey of Neonicotinoids in Honey. Science 2017358 (6359), 109–111.