Bee populations are declining at an unprecedented rate around the globe: fact. Due to the key role that these pollinators play in maintaining world crops, flowers and biodiversity as a whole, the media has latched on to this detail and are generating dramatic headlines at almost the same rate that bees are dying. A whole episode of the most recent series of Black Mirror (warning: spoilers ahead) was dedicated to a possible future filled with murderous robot bees created to replace their biological counterparts (Figure 1). In this blog, I will bravely attempt to separate the cold hard facts from the hyperbolic media jargon and buzzwords (buzzwords…. geddit).
Bees and pesticides: a toxic mix?
Of the many recent articles that have been posted regarding pollinator decline, a substantial amount of them (from publications such as The Guardian, Huffington Post, ITV News and The Los Angeles Times) have covered the human use of pesticides and the subsequent negative effects these substances have on bees. The media seems to have targeted pesticides as the definitive villain of this story and not without reason. A frightening phenomenon called Colony Collapse Disorder (CCD) that is characterised by the sudden death and/or abandonment of the hive of adult worker bees, combined with the presence of the queen and an abundance of food stores within the hive (which suggests that the bees did not starve or leave as a result of the queen leaving) is one of the main causes of pollinator losses (Figure 2); this phenomenon has thus far mostly been observed in the United States – the only country that continues to use the most toxic pesticide compounds, neonicotinoids, for crop management to an excessive degree.1 In addition to this conjunction of circumstances, studies have also shown that exposure to especially toxic pesticides like neonicotinoids can lead to pronounced long-term memory loss and reduced success when foraging for pollen, which may lead to the strange symptoms that characterise CCD.2
Bee-hind the headline
However- before we all get our flaming pitchforks at the ready- there is still no conclusive evidence that pesticides are the sole or even the primary reason that bee populations are declining. Detracting from the current scientific studies on bees and pesticides is the fact that none of them have been undertaken in the natural habitat of bees, but in laboratories; this means that many other factors that may affect bee response are being discounted and therefore these studies may have produced exaggerated results. The use of neonicotinoids, the pesticides that most current research papers investigating bee declines mention, have been banned in the EU since 2013, so are unlikely to continue affecting bee populations outside of the US (let’s not mention Brexit right now) (Figure 3).3 Pesticides can also help to aid bee survival, through the use of certain compounds to eradicate bee habitats of dangerous parasites such as the varroa mite.4 In addition to this, there are many other factors that affect the bee survival (e.g. climate change, habitat loss, diseases and parasites) that may be the actual primary reason between bee declines or may be working in combination with pesticides to drive these declines.5 In other words, pesticides may be the Igor to one of these other factors’ villainous mastermind.
The fine print
To conclude, the media are doing what they usually do and sensationalising the juiciest part of a story to get more attention. Although there is sufficient evidence to believe that pesticides are having a definite effect on bee health and population numbers, there is still far more scientific research that needs to be undertaken to prove to what extent pesticides are affecting these species and how they possibly interact with other factors to cause substantial declines. The media tends to report on real life stories in a more simplistic way with a clear villain and hero; in this case, the evil greedy farmers spraying their pesticides all over the poor defenseless bees of the world. The actual case is far more complex, but unfortunately ‘Bees are dying – the reason might be pesticides but it might also be climate change or parasites or diseases or, um, all of these things actually’ does not make for a great headline. Now let’s all look at this picture of a bee that kind of looks like it’s smiling and be(e) happy (Figure 4).
- Farooqui, T. (2013). A potential link among biogenic amines-based pesticides, learning and memory, and colony collapse disorder: A unique hypothesis. Neurochemistry International, 62(1), 122-136.
- Decourtye, A., Armengaud, C., Renou, M., Devillers, J., Cluzeau, S., Gauthier, M., & Pham-Delègue, M. (2004). Imidacloprid impairs memory and brain metabolism in the honeybee (Apis mellifera L.). Pesticide Biochemistry And Physiology, 78(2), 83-92.
- Suryanarayanan, S. (2015). Pesticides and pollinators: a context-sensitive policy approach. Current Opinion in Insect Science, 10, 149-155.
- Di Prisco, G., Cavaliere, V., Annoscia, D., Varricchio, P., Caprio, E., & Nazzi, F. (2013). Neonicotinoid clothianidin adversely affects insect immunity and promotes replication of a viral pathogen in honey bees. Proceedings of the National Academy Of Sciences, 110(46), 18466-18471.
- Hanula, J., Horn, S., & O’Brien, J. (2015). Have changing forests conditions contributed to pollinator decline in the southeastern United States? Forest Ecology and Management, 348, 142-152.