But what if bees could also provide insights into the health of people and the city? A new study was published today in Environmental Microbiome shows how honey bees reveal information about human health, pathogens, plant life and the environment of different cities.
Our living cities
The UN almost predicts 70% of the human population will live in cities by 2050.
While cities are planned and built with people in mind, they also function as complex, adaptive ecosystems that host a diversity of other living organisms. The health and well-being of people in urban areas can be affected by our interactions with the many invisible things we share our cities with.
It is therefore important to understand which biotic (living organisms such as plants, animals and bacteria) and abiotic (non-living components such as land, water and the atmosphere) components make up our cities. But to collect such samples from all over the city, we need lots of volunteers, time and intensive work.
Honey beehives maintained by urban beekeepers could provide a new, more efficient way to sample the urban microbiome—a collection of local microbes, such as bacteria, fungi, viruses, and their genes.
Urban beekeepers can help save wild bees
Honeybees as collaborators
Honeybees often live in hives of 60,000–80,000 individuals. When a bee reaches a certain age in the hive (about 21 days), they become a forager. Foragers leave the hive in search of nectar, pollen and other resources.
Researchers enlisted the help of honey bees as data collectors in five cities: New York in the United States, Tokyo in Japan, Venice in Italy, and Melbourne and Sydney. In urban areas, honey bee foragers typically travel about 1.5 km from the hive to visit flowers.
During these flights, they can interact with many biotic and abiotic components of the environment and carry traces of these interactions back to the hive. In each city, the team sampled one or more of the following: hive materials including honey, bee carcasses, hive debris (accumulation of material under or at the bottom of the hive), and swab samples from the hive itself.
A city's ‘genetic signature'
The researchers found some unexpected materials in the hives, along with less surprising results. Beehive material showed plant DNA that varied between cities. In Melbourne, the sample was dominated by eucalyptus, while samples from Tokyo contained plant DNA from lotus and wild soybean, as well the soy sauce fermenting yeast Zygosaccharomyces rouxii.
Samples from Venice were dominated by fungi related to wood rot and date palm DNA. The samples also contained bee-related microorganisms, indicating both healthy hives and hives with pathogens or parasites, such as Varroa destructor.
The more surprising findings included genetic data in the Sydney sample from a species of rubber-degrading bacteria, Gordonia polyisoprenivorans. DNA from a pathogen is spread to humans via cat fleas called Rickettsia felis were also found in samples and appeared in Tokyo hives over time.
How do we interpret these results?
The study offers a new and interesting use of urban beehives – the potential to monitor human health and pollution in cities. However, there were certain limitations in the work. The differences in microbiomes between cities were based on small sample sizes – one hive in Venice, three in New York, two in Melbourne, two in Sydney and 12 in Tokyo.
Because of these limitations, differences between cities can potentially be attributed to variation in hives and their genetics. Future work with long-term studies with more hives would help reveal whether the unique genetic signatures were due to differences between cities or between hives or even time periods.
The authors have suggested that debris from honey beehives may provide a snapshot of the microbial landscape in cities. In the future, they argue, such methods could even help monitor antibiotic resistance and the spread of viral diseases, but much more sampling and validation will be needed to achieve these goals.
Scarlett Howard receives funding from the Australian Research Council (ARC) and has previously received funding from the Australian Government Research Training Program (RTP) Scholarship, RMIT University, Fyssen Foundation, L'Oreal-UNESCO for Women in Science Young Talents French Award, Deakin University, Monash University, the Hermon Slade Foundation and the Australian Academy of Sciences. She is affiliated with Pint of Science Australia.
Originally published in The conversation.
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