The Honey Bees are Going Viral; but it's Not the Bees Knees
When we go to our favorite local grocery store, or local farmer’s market, and choose out our groceries from that carefully prepared list we may not be thinking about all of the hard work that goes into our foods we eat. Sure, we may think about the quality of the soil the seeds are grown in and whether or not it may or may not be organically sourced, but are we thinking beyond that? Besides humans, who else is involved in ensuring we can even purchase our delicious foods? The honey bee.
The Honey Bee Apis mellifera
The honey bee (Apis mellifera) is a buzzing population of hard workers who are responsible for the successful pollination of 1/3 of our distinct agricultural crops. These crops include vegetables, fruits, nuts, and also oilseeds (Ullah et al., 2020). The honey bee is also the most frequent visitor of our crops worldwide and is considered vital to keep up with species diversity within various ecosystems (Wang et al., 2021). In a review published by the Journal of Biological Sciences titled Viral impacts on honey bee populations: A review, it was estimated that the pollination of these crops by bees is worth billions of dollars in services. This puts a 9.5% added value on global crops (Ullah et al., 2020). So you can imagine how an impact on our bee populations can also have an impact on the global economy. Products that come from honey bee crops include wax, royal jelly, bee venom, honey, pollen, and propolis (Ullah et al., 2020). From these, even more products can actually be made since wax and honey are common ingredients. The A. mellifera species is native to Africa, Europe, and the Middle East but they are globally distributed for pollination services. This demand has led to an increase in colonies by more than 45% in the last 60+ years. Unfortunately, in the last 15 years, there have been dramatic winter crop losses being reported around the world
Factors in Bee Population Decline
It is no hidden secret that when you enter near or into urbanized areas, you can now find a fast-food chain, coffee shop, or even a bank at almost every major intersection. That is not even mentioning retail shopping or auto businesses. Insect biodiversity has been shown to be negatively impacted by the expansion of urban areas and the intensity of the agricultural industry. In addition, it was found that increasing the proportions of green lawns also had a negative impact (Lanner et al., 2019). The reason for more lawns is typically because more homes are being developed because of the increasing population. This increase in population leads to an increase in the food supply demand, which leads to a higher demand for pollination services. This can actually cause changes in the honey bees' behavior (Geffre et al., 2020) which can include physiological impairments of individuals to dysfunctional social behaviors. This can lead to colony collapse (Daisley et al., 2020b). A recent study published in Urban Ecosystems which was focused on species richness within community gardens found that a major factor in the insect decline is the intensity of agriculture. While analyzing 69 community gardens in Vienna, researchers found that urban gardens actually helped to conserve local biodiversity and that some of the plants within these urban gardens provided foraging resources for the wild bees. It also provided a home for 113 different wild bee species, which is about ¼ of the known species which frequent Vienna. An interesting part of this research was finding that an artificial structure similar to bamboo made a comfortable home for a rare species of bee not found in that geographical area (Lanner et al., 2019). With this increase in urbanization, which is due to an increase in the human population, there also comes the factor of addressing climate change.
Much of the research that we hear about on local news channels involves how climate change affects mammals, but not necessarily insects. In a 2020 study titled Climate change contributes to widespread declines among bumblebees across continents, researchers reviewed a database of about 550,000 georeferenced occurrence records in regards to 66 bumblebee species. These locations were divided into quadrants measuring 100km by 100km. The time frames analyzed were from 1901-1974 and 2000-2014. For each of these time frames, detection-corrected occupancy models for estimated probability species occurrence was used. They concluded that when it came to an increase in the number of hot days, it had a negative impact on the bumblebees by increasing their extinction rates, reducing colonization, reducing site occurrence, and decreasing the species richness. This can actually impair ecosystem services. When we further break this down, the levels of temperature and precipitation are what affected bumble bee mortality and fecundity directly as well as indirectly through the changes which take place with floral resources (Soroye et al., 2020). This is fairly general information in my opinion. When you think of a typical garden bed full of beautiful flowers and plants, they thrive in the proper environments of adequate sunlight, healthy soils, and adequate watering. When any of these are impacted, it can have an effect on our plants and they suffer. If I was a bee, I don’t think I would be too attracted to dying flowers, or even fake ones…
Speaking of artificial flowers, a published article in the Journal of Hazardous Materials has found that there is a great exposure risk to honey bees Apis mellifera L. when it comes to microplastics. Microplastics are plastic particles smaller than 5mm in diameter. These are the byproducts of larger plastics degradation.
Within 14 days of exposure to primary microplastics (PMPs) and secondary microplastics (SMPs) alone, researchers found that there was a decrease in the diversity of the bees’ gut microbiota which was accompanied by changes to the core microbial population structure. In addition, the exposures to the microplastics also led to alternations in gene expressions which included antioxidative (CAT), detoxification (CYPQ1 and GstS3), as well as immune system-related genes (Domeless, Hopscotch, and Symplekin) in the gut. These microplastics which negatively affect the microbiota of the honey bee have also been identified in soil, and even within terrestrial organisms such as snails. The researchers concluded that microplastics have a direct negative effect on food chains, plants, insects, and animals that are also directly consumed by humans (Wang et al., 2021).
According to Wang et al., in a study that focused on survival, oxidative & immune stress, gut microbiota homeostasis, bioaccumulation in guts, and the synergistic actions with the antibiotic tetracycline, the PS-MPs (primary and secondary microplastics) had a variety of effects. Researchers showed that when exposed to PS-MPs, honey bees had a decrease in gut bacterial diversity. This then results in changes in the bee microbiome composition, which was accompanied by altered gene expressions which are critical to oxidative damage, detoxification, and immunity. Microplastics are known to have more chemical effects than physical effects which is what makes this a complex topic. These physical effects are due to “…interactions with biological membranes, organelles, and molecules, which finally result in inflammation, changes in membrane permeability, and oxidative stress.” Additionally, the study revealed that for honey bees, the microplastics might not be as lethal by themselves, but, when the exposure was combined with the drug tetracycline, this actually dramatically increased the lethality of microplastics (Wang et al., 2021). This shows that the synergistic effects of substances with other substances can be of vital importance in how they work within the body; whether human or insect.
The threat of viruses to honey bee colonies is not new information being researched, but, it is being researched more rapidly since the human diet relies on the successful pollination of honey bees, and viral infections are spreading globally. Until recently, it was considered rare to find severe symptomology, including colony loss. In the U.K. it is considered an emergent disease (Budge et al., 2020, p. xx; Ullah et al., 2020). There are currently over 20 viruses that infect honey bees throughout the world, and these infections can cause colonies to collapse. In the year 2007, only one English county had been infected in Europe. By the year 2017, 39 of the 47 English counties were infected and 6 of the 8 Welsh counties (Budge, et al., 2020). Colony losses have been noted in many countries including England, the United States, Australia, Thailand, France, Poland, South Korea, Japan, China, as well as Vietnam. These are some of the most prominent viruses:
• ABPV – Acute Bee Paralysis Virus
• BQCV – Black Queen Cell Virus
• KBV – Kashmir Bee Virus
• SBV – Sacbrood Virus
• CBPV – Chronic Bee Paralysis Virus
• SBPV – Slow Bee Paralysis Virus
• IAPV – Israeli Acute Paralysis Virus
• DWV – Deformed Wing Virus
• VDV1 – Varroa Destructor Virus
• LSV – Lake Sinai Viruses (Ullah et al., 2020).
You can see that these viruses are found globally, which makes this current issue so prevalent for researchers to find solutions to. Commonly, viral infections of honey bees are treated with antibiotics such as oxytetracycline. Due to the widespread use of these antibiotics, this had led to a global dissemination of antimicrobial resistance (Daisley et al., 2020a).
An interesting novel approach to these infections of honey bees is the use of Lactobacillus strains which are commonly used as probiotics (Reid, 1999). Published in the ISME Journal 2020 is an in-vitro study in which researchers supplemented a hive with the probiotic lactobacilli in the form of a nutrient patty manufactured by BioPatty. The researchers wanted to see how this would affect colony resistance towards a naturally occurring AFB (American foulbrood) outbreak which is caused by an infection from the Paenibacillus larvae. This infection has rendered entire hives completely dysfunctional. The results of this study showed that Lactobacilli strains could offer up an advantage over the traditionally used antibiotics, such as oxytetracycline. It offers this by inhibiting germination and actually actively reducing the cell viability of P. larvae. This means that the use of BioPatty could possibly help to modulate honey bees’ immunity, reduce pathogen loads, and improve their survival rates during an infection outbreak (Daisley et al., 2019). If financially affordable to beekeepers, and in quantities needed for colonies, this seems like an ideal proactive option in tending to the safety and health of honey bees.
The use of widespread antibiotics is one of the factors contributing to the global dissemination of antimicrobial resistance. A study that tested three immunostimulatory strains of Lactobacillus in combination with the common over the counter treatments, found that there were positive benefits. These included partially restoring the deficits in hive productivity, beta diversity of gut microbiota, and immune responsiveness which was altered due to antibiotic usage (Daisley et al., 2020a).
Bees are a glorious insect which the human species definitely takes for granted. For such a tiny insect with such a big responsibility on their wings to pollinate our crops, you would think that we would focus more to ensure their survival so that we can ensure our own survival as humans since we rely on them in the process of us obtaining the foods we eat. In addition, these little bees can have a major economic impact due to colony loss and lack of pollination services for our crops. Despite recent successful studies with the use of Lactobacillus strains as probiotics, further research would be needed into this niche of insect wellness if we as humans are to survive. For now, studies show that community gardens can have positive benefits in the world of crop pollination and the survival of the bees and this is something that can be easily implemented throughout the world.
Budge, G. E., Simcock, N. K., Holder, P. J., Shirley, M. D., Brown, M. A., Van Weymers, P. S., Evans, D. J., & Rushton, S. P. (2020). Chronic bee paralysis as a serious emerging threat to honey bees. Nature Communications, 11(1). https://doi.org/10.1038/s41467-020-15919-0
Daisley, B. A., Chmiel, J. A., Pitek, A. P., Thompson, G. J., & Reid, G. (2020b). Missing microbes in bees: How systematic depletion of key symbionts erodes immunity. Trends in Microbiology, 28(12), 1010-1021. https://doi.org/10.1016/j.tim.2020.06.006
Daisley, B. A., Pitek, A. P., Chmiel, J. A., Al, K. F., Chernyshova, A. M., Faragalla, K. M., Burton, J. P., Thompson, G. J., & Reid, G. (2019). Novel probiotic approach to counter Paenibacillus larvae infection in honey bees. The ISME Journal, 14(2), 476-491. https://doi.org/10.1038/s41396-019-0541-6
Daisley, B. A., Pitek, A. P., Chmiel, J. A., Gibbons, S., Chernyshova, A. M., Al, K. F., Faragalla, K. M., Burton, J. P., Thompson, G. J., & Reid, G. (2020a). Lactobacillus spp. attenuate antibiotic-induced immune and microbiota dysregulation in honey bees. Communications Biology, 3(1). https://doi.org/10.1038/s42003-020-01259-8
Geffre, A. C., Gernat, T., Harwood, G. P., Jones, B. M., Morselli Gysi, D., Hamilton, A. R., Bonning, B. C., Toth, A. L., Robinson, G. E., & Dolezal, A. G. (2020). Honey bee virus causes context-dependent changes in host social behavior. Proceedings of the National Academy of Sciences, 117(19), 10406-10413. https://doi.org/10.1073/pnas.2002268117
Lanner, J., Kratschmer, S., Petrović, B., Gaulhofer, F., Meimberg, H., & Pachinger, B. (2019). City dwelling wild bees: How communal gardens promote species richness. Urban Ecosystems, 23(2), 271-288. https://doi.org/10.1007/s11252-019-00902-5
Reid, G. (1999). The Scientific Basis for Probiotic Strains of Lactobacillus. Applied and Environmental Microbiology, 65(9), 3763-3766. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC99697/
Soroye, P., Newbold, T., & Kerr, J. (2020). Climate change contributes to widespread declines among bumble bees across continents. Science, 367(6478), 685-688. https://doi.org/10.1126/science.aax8591
Ullah, A., Tlak Gajger, I., Majoros, A., Dar, S. A., Khan, S., Kalimullah, Haleem Shah, A., Nasir Khabir, M., Hussain, R., Khan, H. U., Hameed, M., & Anjum, S. I. (2020). Viral impacts on honey bee populations: A review. Saudi Journal of Biological Sciences. https://doi.org/10.1016/j.sjbs.2020.10.037
Wang, K., Li, J., Zhao, L., Mu, X., Wang, C., Wang, M., Xue, X., Qi, S., & Wu, L. (2021). Gut microbiota protects honey bees (Apis mellifera L.) against polystyrene microplastics exposure risks. Journal of Hazardous Materials, 402, 123828. https://doi.org/10.1016/j.jhazmat.2020.123828