Bumblebees found to do better in urban settings than in agricultural areas

June 27, 2018 by Bob Yirka, Phys.org report
Credit: CC0 Public Domain

A team of researchers with the University of London and Imperial College London has found through field experiments that bumblebee colonies tend to do better in urban environments than agricultural environments. In their paper published in Proceedings of the Royal Society B, the group describes their study and what they found.

Bumblebees are generally considered to be one of the friendlier bees that people encounter. Despite their large, round size, they tend to elicit less fear due to their non-threatening behavior. And according to a study done by the team in Britain, they also appear to find more success in urban areas than they do in agricultural areas. They came to this conclusion by conducting an extensive field study.

The study consisted of capturing queen bees in a local park and putting them into where they laid eggs. The nest boxes were then placed at 38 sites between Basingstoke and London and monitored for approximately 10 weeks—the average lifespan of a colony. Each colony received a visit once a week—at night when all members would be present. During each visit, the researchers counted all members of the and noted how much nectar and pollen had been stored. They also removed cuckoo bumblebees (other bee species that lay their eggs in bumblebee colonies) and gynes (males capable of reproducing).

The researchers found that that in cities produced far more males and gynes than did those in agricultural areas. They also found that both city and village colonies had much higher populations than the agricultural colonies. Those colonies located in also tended to have more cuckoo bumblebee invasions.

The researchers were not able to say for sure why the bumblebees appeared to do better in urban and village settings, but suggest it could be due to a variety of factors. Agricultural areas tend to have crops that only bloom for a short time, they note, and which are exposed to pesticides and other toxic chemicals. Cities and villages, on the other hand, have a wide variety of flowers that bloom at different times.

Explore further: Environmental threats put bumblebee queens under pressure

More information: Ash E. Samuelson et al. Lower bumblebee colony reproductive success in agricultural compared with urban environments, Proceedings of the Royal Society B: Biological Sciences (2018). DOI: 10.1098/rspb.2018.0807

Abstract
Urbanization represents a rapidly growing driver of land-use change. While it is clear that urbanization impacts species abundance and diversity, direct effects of urban land use on animal reproductive success are rarely documented. Here, we show that urban land use is linked to long-term colony reproductive output in a key pollinator. We reared colonies from wild-caught bumblebee (Bombus terrestris) queens, placed them at sites characterized by varying degrees of urbanization from inner city to rural farmland and monitored the production of sexual offspring across the entire colony cycle. Our land-use cluster analysis identified three site categories, and this categorization was a strong predictor of colony performance. Crucially, colonies in the two clusters characterized by urban development produced more sexual offspring than those in the cluster dominated by agricultural land. These colonies also reached higher peak size, had more food stores, encountered fewer parasite invasions and survived for longer. Our results show a link between urbanization and bumblebee colony reproductive success, supporting the theory that urban areas provide a refuge for pollinator populations in an otherwise barren agricultural landscape.

Related Stories

Scandinavian bumblebees survive by incubating their eggs

June 11, 2018

It is a sure sign that spring is in the air: The sight of a bumblebee queen buzzing around spring flowers on a sunny day. But sometimes, when she is flying around, she is actually not looking for flowers, but on the hunt ...

'Virtual safe space' to help bumblebees

May 22, 2018

The many threats facing bumblebees can be tested using a "virtual safe space" created by scientists at the University of Exeter. Bumble-BEEHAVE provides a computer simulation of how colonies will develop and react to multiple ...

Recommended for you

What makes vertebrates special? We can learn from lancelets

November 21, 2018

Scientists once thought that humans must have 2 million genes to account for all our complexity. But since sequencing the human genome, researchers have learned that humans only have about 19,000 to 25,000 genes—not many ...

Scientists help identify key hantavirus receptor

November 21, 2018

A global team of investigators has identified a key protein involved in Hantavirus Pulmonary Syndrome (HPS), a serious and sometimes fatal respiratory disease, according to research published today in the journal Nature.

2 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

Jurupa Guy
not rated yet Jun 30, 2018
I'd love for them to test Darwin's hypothesis that it's the number of spinsters with cats, since the cats eat the mice that destroy the bumblebee's nest. There are likely lots more cats in urban areas. :-)
ZoeBell
Jul 01, 2018
This comment has been removed by a moderator.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.