Britain's urban areas are home to more types of wild bee than farmland, a study has found.
Flowers planted in gardens and allotments provide a valuable food source for bees across the year, according to research.
Scientists counted honey bees, bumble bees and other pollinating insects, in and around some of the UK's largest towns and cities.
Urban habitats can provide a valuable role in bee conservation, they say.
Honey bees, bumble bees and other insects that pollinate plants are under threat from habitat loss, pesticides and diseases.
But new research suggests that bees and other pollinating insects thrive as well in towns and cities as they do in farms and nature reserves.
A team led by Dr Katherine Baldock of the University of Bristol said urban landscapes - making up 7% of the UK - deserve more attention in the drive to protect bees from decline.
"Urban areas could be managed in a way to be good to pollinators," she told BBC News. "What we need to know next is which habitats within urban areas are good for pollinators."
While farms are often planted with swathes of one crop, gardens and allotments provide a mixed source of flowers across the year, which is a valuable habitat for insects, she added.
Commenting on the study, published in the journal, Proceedings of the Royal Society of London B, Dr Dave Goulson of the University of Sussex said the research showed that there were more species of wild bee living in suburbia than in farmland.
"This is an indictment of modern farming methods, but is also greatly encouraging for those gardeners who put in wildlife-friendly flowers and leave a little space for nature," he said.
"There is huge potential to turn our suburban sprawls into giant nature reserves if we can get more and more gardeners on board."
The study looked at the abundance and richness of pollinating insect species in and around Bristol, Cardiff, Swindon, Reading, Greater London, Southampton, Leeds, Sheffield, Kingston-upon-Hull, Edinburgh, Glasgow and Dundee.
A total of 7,412 insects were recorded visiting flowers. Bee abundance did not differ between landscapes, but the richness of species was higher in urban areas than on farmland.
The researchers - from the universities of Bristol, Leeds, Newcastle, Reading, Edinburgh and Cardiff - say urban areas are expanding, and could act as important habitats for insects as farming becomes more intensive.
Insect pollination has been valued at around £690M per year for UK crop production.
"The findings offer incentives for policy makers to improve the quality of existing green spaces in urban areas," said Prof Jane Memmott of the University of Bristol.
The study was funded by The Insect Pollinators Initiative, which is joint-funded by the Biotechnology and Biological Sciences Research Council (BBSRC), Defra, the Natural Environment Research Council (NERC), the Scottish Government and the Wellcome Trust.