City living pushed bumblebees to evolve bigger and smarter than their country cousins

‘Larger bumblebees can see better, they have larger brains and are better in learning and memory’

Daily Telegraph Reporter BUMBLEBEES are bigger and more hardworking in cities than in the countryside, according to a new study.

Researchers found that the body size of bumblebees in cities is larger than their rural counterparts. They say that it means urban bees are able to provide a better pollination service to the ecosystem.

A bigger body size means they are also better suited to an urban environment, where green spaces are separated by a concrete jungle.

Dr Panagiotis Theodorou, of the Martin Luther University Halle-wittenberg (MLU) in Germany, said: “Living in a city can have both benefits and disadvantages for bumblebees.

“On the one hand, residential gardens and balconies, allotment gardens, botanical gardens and city parks provide rich food sources for bumblebees.

On the other, cities are significantly warmer than their surrounding rural areas.”

Dr Theodorou said: “In addition, impervious surfaces, streets and large buildings create considerably smaller habitats that are isolated from one another. These might pose a challenge to bumblebees.”

Nearly 2,000 bumblebees were collected from metropolitan areas and their rural surroundings in Germany.

Three locally common species, the red-tailed bumblebee (Bombus lapidaries), the common carder bee (Bombus pascuorum) and the buff-tailed bumblebee (Bombus terrestris) were concentrated on by the researchers. The team measured the body size of each bumblebee and found the city dwellers were larger across all three species.

Co-author Dr Antonella Soro, also at MLU, said: “Larger bumblebees can see better, they have larger brains and are better in learning and memory.

“They are also less likely to be attacked by predators and can travel greater distances, which is an advantage in a fragmented landscape such as the urban one. The number of seeds produced by potted red clover plants at each location was also counted to determine the level of pollination.

“Large bumblebees visit more flowers per flight and are capable of depositing a higher number of pollen grains on stigmas, which makes them better pollinators.”

The findings were published in the journal Evolutionary Applications.