Environment: Honeybees provide a snapshot of city landscapes and health

Urban honeybees could be used to gain insights into the microbiomes of the cities in which they forage, which could provide information on both human and hive health, reports a study published in the journal environmental microbiome.

Cities were built for human habitation, but they are also spaces that host a wide variety of living species, and understanding this diverse landscape is important for urban planning and human health. However, sampling the microbial landscape in a way that covers large areas of a city can be labor intensive.

Elisabeth Hanaff and colleagues investigated the potential of honey bees (Apis mellifera) to help collect samples of microorganisms around cities, since honey bees are known to forage daily within up to one mile of hives in urban environments. They sampled various materials from three hives in New York as part of an experimental study, and found diverse genetic information, including from environmental bacteria, in the debris accumulated at the bottom of the hives. Subsequent sampling of hive debris in Sydney, Melbourne (Australia), Venice (Italy), and Tokyo (Japan) indicates that each site has a unique genetic signature as seen by honey bees.

In Venice, fungi related to wood rot and date palm DNA dominated the genetic data. In Melbourne, the sample was dominated by eucalyptus DNA, while the sample from Sydney showed little plant DNA but contained genetic data from a rubber-corrupting bacterium (Gordonia polyisoprenivorans). The Tokyo samples included plant DNA from wild lotus and soybeans, as well as the soy sauce-fermenting yeast Zygosaccharomyces rouxii. In addition, the authors synthesized genetic material from the beehive debris of Rickettsia felis (“cat scratch fever”), a pathogen spread to humans by cat scratches. These findings indicate the potential of this as a method of surveillance but are at present too preliminary to indicate that this is an effective method for monitoring human disease.

Hive debris also contains microorganisms associated with bees, likely coming from honeybee body parts found in the debris. Based on 33 samples of beehives across the four subsequent cities, the authors found microorganisms known to bees, the presence of which indicates a healthy hive, and in some beehives pathogens of bee diseases, such as Paenibacillus larvae, Melissococcus plutonius, or the parasite Varroa destruction, were detected. The authors suggest that these results indicate that urticaria can additionally be used to assess the general health of urticaria.

The authors concluded that honey bee hive debris collected by honey bees provides a snapshot of the microbial landscape of urban environments and can be used in conjunction with other measures to assess microbial diversity and the health of cities and, in turn, honey bees.