Secrets of the cities are kept by the bees

For scientists studying the health of a city and its inhabitants, their most powerful tool may just be the honeybee.

That is because when honeybees go foraging, they collect more than just pollen and nectar. As they navigate through their environment, micro-organisms and other tiny particles can also cling to the bees’ fuzzy little bodies, which the pollinators then shed as they enter their hives.

And since pollinators tend to forage within a kilometre radius of their hives in urban areas, there is valuable information about a city or even a neighbourhood in the honey they produce, on their bodies and in the debris at the bottom of hives.

“Honeybees will gather a vast number of microbes day to day, far beyond things they are seeking out. They’ve been optimised by evolution to do everything that the swabs do,” said Kevin Slavin, a professor at MIT Media Lab, during a media briefing on a new report in the journal Environmental Microbiome. The research aims to establish a feasible method for collaborating with beekeepers and their colonies of honeybees for studying the microbiome of cities.

A microbiome is the unseen communities of microbes, fungi, viruses and bacteria that live inside and around us, playing a key role in the functioning and health of the urban environment and the human population, as well as plants and animals. Previous research has linked exposure to a diverse microbiome to better health outcomes.

In the near future, understanding microbial environments can become crucial to understanding the many ways in which health and environmental inequalities disproportionally affect marginalised communities, said Slavin.

To test if bees can be used to “swab” the city, Slavin and a team worked with beekeepers to collect and analyse microbes from samples of honey, honeybee parts, and hive debris across five cities — New York, Venice, Tokyo, Melbourne and Sydney.

The study began in New York City, where researchers compared microbes from Brooklyn and Queens to show how microbes might differ from one neighbourhood to another. The material gathered from hive debris varied the most among the locations.

Meanwhile, in Venice, where many buildings sit atop wooden pilings submerged in water, data consisted of fungi related to wood rot, for example. And in Tokyo, the researchers found genetic traces of a fermenting yeast used in the production of soya sauce and miso paste.

“Cities have their own microbial signatures, which are also interestingly related to the cultural and geographical context in which those cities have emerged,” said co-author Elizabeth Hénaff, a computational biologist at New York University Tandon School of Engineering.

More than that, the study demonstrated how the materials gathered from beehives could potentially aid health officials in pathogen surveillance.

There are several methods for studying the microbiome of a city, including testing wastewater, which has been used to detect the presence of drugs. But the researchers say that method focuses on things that humans have processed.

“What about the city or a neighbourhood as a whole?” said Slavin. “What about everything that isn’t processed by humans?”/Bloomberg