The city life of bumblebees

A recent report from the United Nations found that more than half of the world population today resides in urban areas (United Nations, 2014). While this makes perfect sense for people (since we work in urban areas, buy food, clothes and can find there all we need) we should note that urban areas are having effects on the animal kingdom as well. Common beliefs suggest us that in most cases the animal kingdom is impacted for the worst (Aronson et al. 2014), but there are few species that seem to have good time in cities (Kark et al. 2007). Just take a walk in Chicago and you can see rats as big as cats, or go to Venice and you will see how well pigeons (in Italy we call them the rats of the sky) have adapted to urban life. You may not know but there is another species that have adapted pretty well. I am talking about bees. British scientists have studied how urban bees live compared to rural bees and the results were surprising. I thought that bees would prefer living in rural areas but this study revealed that instead city bees have a better life.
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Let’s delve more deeply into the study: The scientists collected 176 queen bees and they tested them for the presence of parasites. They used only parasite-free queens for the study, so the number was reduced to 170 queens. They positioned these queens in 38 different sites (some in agricultural areas, some in small villages and some in cities) with a distance of at least 1.5 km from one another (Samuelson et al. 2018). They tracked how well the bees were doing for a few weeks, to be specific they measured how much the bees were growing, their reproductive output, how much food they were storing and screened for the presence of parasites. Surprisingly, they found that bees living in villages and cities were more likely to generate live sexual offspring compared to agricultural colonies. _{Image CCO Creative Commons released by The royal society publishing [Source](http://rspb.royalsocietypublishing.org/content/285/1881/20180807)}

This obviously also resulted in a higher overall number of bees in urban colonies relative to agricultural colonies. _{Image CCO Creative Commons released by The royal society publishing [Source](http://rspb.royalsocietypublishing.org/content/285/1881/20180807)}
There was significantly less food stored in the agricultural colonies compared to urban ones and bees living in rural areas were dying also more quickly. This may seem counter-intuitive but urban environments are becoming a refuge for bees that have seen their floral resources dramatically reduced by agricultural practices (Carvell et al. 2006). Especially when cities and towns have garden and parks they can offer high diversity of floral resources (Loram et al. 2008). This is positive, even if most urban flowers are chosen for their esthetic appeal rather than their nutritional potential (Garbuzov and Ratnieks 2014).

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_{Image CCO Creative Commons - [Source](https://pixabay.com/en/bee-flying-holding-honey-buckets-45792/)}

Desneux, Nicolas, Axel Decourtye, and Jean-Marie Delpuech. 2007. “The Sublethal Effects of Pesticides on Beneficial Arthropods.” Annual Review of Entomology 52(1): 81–106. http://www.annualreviews.org/doi/10.1146/annurev.ento.52.110405.091440.



Garbuzov, Mihail, and Francis L. W. Ratnieks. 2014. “Quantifying Variation among Garden Plants in Attractiveness to Bees and Other Flower-Visiting Insects” ed. Ken Thompson. Functional Ecology 28(2): 364–74. http://doi.wiley.com/10.1111/1365-2435.12178.



Goulson, Dave et al. 2010. “Effects of Land Use at a Landscape Scale on Bumblebee Nest Density and Survival.” Journal of Applied Ecology 47(6): 1207–15. http://doi.wiley.com/10.1111/j.1365-2664.2010.01872.x.



Kark, Salit, Andrew Iwaniuk, Adam Schalimtzek, and Eran Banker. 2007. “Living in the City: Can Anyone Become an ?Urban Exploiter’?” Journal of Biogeography 34(4): 638–51. http://doi.wiley.com/10.1111/j.1365-2699.2006.01638.x.



Loram, Alison, Ken Thompson, Philip H. Warren, and Kevin J. Gaston. 2008. “Urban Domestic Gardens (XII): The Richness and Composition of the Flora in Five UK Cities.” Journal of Vegetation Science 19(3): 321–30. http://doi.wiley.com/10.3170/2008-8-18373.



United Nations. 2014. World Urbanization Prospects. United Nations. https://esa.un.org/unpd/wup/publications/files/wup2014-highlights.pdf.



Osborne, Juliet L. et al. 2007. “Quantifying and Comparing Bumblebee Nest Densities in Gardens and Countryside Habitats.” Journal of Applied Ecology 45(3): 784–92. http://doi.wiley.com/10.1111/j.1365-2664.2007.01359.x.


Samuelson, Ash E., Richard J. Gill, Mark J. F. Brown, and Ellouise Leadbeater. 2018. “Lower Bumblebee Colony Reproductive Success in Agricultural Compared with Urban Environments.” Proceedings of the Royal Society B: Biological Sciences 285(1881): 20180807. http://rspb.royalsocietypublishing.org/lookup/doi/10.1098/rspb.2018.0807.



Senapathi, D. et al. 2015. “The Impact of over 80 Years of Land Cover Changes on Bee and Wasp Pollinator Communities in England.” Proceedings of the Royal Society B: Biological Sciences 282(1806): 20150294–20150294. http://rspb.royalsocietypublishing.org/cgi/doi/10.1098/rspb.2015.0294.


Sirohi, Muzafar Hussain, Janet Jackson, Mike Edwards, and Jeff Ollerton. 2015. “Diversity and Abundance of Solitary and Primitively Eusocial Bees in an Urban Centre: A Case Study from Northampton (England).” Journal of Insect Conservation 19(3): 487–500. http://link.springer.com/10.1007/s10841-015-9769-2.

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