Bees in the City : 19 IS URBANISATION GOOD OR BAD FOR BEES? Bees in the City Liz Samuelson R


oyal Holloway, University of


London, is carrying out a study this summer looking at the relationship between urbanisation and the three main threats to bees – forage, pesticides and disease – and we need your help. Urban areas are expanding and, at the same time, the number of people keeping bees in cities is increasing. In London, there are now more than 1200 beekeepers – three times as many as five years previous. But the jury is still out on whether urbanisation is a threat or salvation for honey bees. With claims of vast honey crops clashing with warnings of unsustainable hive densities, the Bees in the City project aims to help clear up the uncertainty.


Forage


While many studies have found that wild bees thrive in cities, honey bees depend on a much higher amount of forage to bring in enough nectar and pollen to support their large colonies. Are urban bees getting enough to eat? Research on waggle dances in Brighton found that rural bees flew almost twice as far to find food in the summer months than urban bees, suggesting forage is more readily available in the city. In addition, a study from


Worcester and one in Washington, DC, both showed that urban honey bees collect a


May 2015 Vol 97 No 5 extensively on


public lawns in Britain in 2012. This has been shown to have drastic consequences for bees foraging on clover flowers. Bees in the City aims to shed some light on this topic by analysing pesticide residues in urban and rural hives.


Parasites


Disease is a real threat to honey bees and scientists have suggested that high densities of new beekeepers in cities may increase the risk of spreading disease. On the other hand, data from the National Bee Unit (NBU) show that Greater London had only 15 American foul brood (AFB) cases between 1999 and 2015, placing it 26th out of 60 counties for AFB cases despite supporting above- average hive densities. Bees in the City will use DNA testing to compare prevalence of deformed wing virus (DWV), Nosema apis and Nosema ceranae, and varroa boards to compare mite infestation levels between city and country.


We Need Your Help Beekeeping on the roof at Royal Holloway, University of London


higher diversity of pollen. However, other research has suggested the opposite. A recent Ohio study found that city bees stored less food. A USA-wide analysis found bees in more urbanised states suffered higher colony losses and produced smaller honey crops. Although cities tend to be full of flowers, a large percentage of these are useless to bees. A survey of the flowering plants in a managed park in Lewes found 77% were unattractive to pollinators. It may be that there is insufficient forage to support the high hive densities of cities like London. This is one area where research is needed.


This year, the Bees in the City


project is looking at pollen collected by London bees compared with rural bees, to see which plants are being visited.


Pesticides


Pesticides, particularly neonicotinoids, have been shown to harm bees in agricultural areas. However, little is known about urban pesticide effects. A quick look at the Chemicals Regulation Directorate database shows that 198 pesticide products are approved for use on ornamental plants in the UK, including two neonicotinoids. One of these, imidacloprid, was used


Bees in the City kicks off this year by comparing colonies in London with those in the surrounding countryside. We are looking for beekeepers who would be happy for us to visit their apiaries on two occasions this summer to take small samples for nosema and DWV screening, pollen analysis for foraging habits, and pesticide screening. ♠


Do you keep bees in Greater London, Kent, Buckinghamshire, Essex, Hertfordshire, Surrey or Berkshire? If you have any questions or would like to take part, please e-mail Liz Samuelson at elizabeth. samuelson.2014@live.rhul. ac.uk


www.bee-craft.com


C Martin


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