Urban Bees Doing Better?

For some years now, bee populations have been in dramatic decline with both commercial honey-bee hives and colonies of wild bees being severely affected. The loss of these incredibly important pollinator populations will have dire consequences for our standard of living as all of our foodstuffs, as well as those we feed to livestock, which rely on flowers being pollinated prior to the production of food will be seriously diminished. The loss of pollinators will also significantly affect the range of wild flowers and plants that adorn our countryside. It was thus interesting to catch up on the progress of some of the investigations into this problem.

Disappointingly, although investigations continue, little real progress seems to have been made in respect of 2 significant issues. The first, a major cause of devastation for amateur and professional bee-keepers alike, has been the spread of parasitic Varroa destructor mites and associated viruses. Thought to have been introduced to Britain about 30 years ago, through the movement of infected honey-bees, the infestations can sometimes be controlled chemically, but some of these treatments have a major impact on the survival of the colony in other ways. Although researchers have found that some honey-bees fastidiously remove mites and infected larvae from their colonies and can thus cope a little better, even these colonies require help to overcome significant infections, so more work is required to identify and propagate a solution to this problem. Thankfully, British wild-bee populations aren’t affected by this mite.

However, wild bees certainly seem to be affected by a second important issue, namely the increased deployment of neonicotinoids to protect crops from widespread damage by aphids, caterpillars and other insects. Mounting evidence that these insecticides were affecting honey bees and other pollinators led the European Union recently to ban the use of most classes of this form of treatment. Again, though, we do not yet have a detailed understanding of how these treatments affect the sizes and behaviours of wild bee colonies, so more work is required to improve our ability to protect crops whilst eliminating the threat to the pollinators that are so vital to our lives.

Furthermore, some observers continue to point out that the start of the catastrophic collapse in Britain, at least, precedes both the arrival of the Varroa mite on our shores and the wide-scale deployment of neonicotinoids within our farming communities. They point out that there must therefore be other, probably man-made, causes which need to be addressed, so other small studies are underway.

In one study, bees living in roof-top hives in London seem to be doing better than those living in the countryside, and it is suggested that this is because these bees have access to a wide range of different pollen-bearing trees, shrubs and flowers during their foraging flights than some of their country cousins do. Dotted around the city’s streets, parks, gardens, and flower boxes, plants are providing valuable oases of nectar and pollen for hard-pressed bees. Furthermore, city bees across the world, including Birmingham and Paris, also produce more honey than their country compatriots. It will therefore be interesting to see how the bee-friendly bus stops, first used in Utrecht and recently adopted by at least 3 British cities, help to prop up urban bee communities by supplementing other food sources.

In addition, other studies have shown that field margins with a high wild-flower content have 5 times as many bumblebee visitors and significantly more solitary bee visitors than margins which are largely grass and that monitored plants close to these flower strips produce much more seed than those adjacent to grass strips. Hopefully, farmers might be persuaded of the increased value of such flowery patches and thus provide more resource for bees and pollinators across the countryside. Furthermore, a 100-year decline in bee populations in around 20 different areas of countryside has recently been associated with the progressive conversion of the local areas from mosaics of mixed habitats to those where large areas are now monocultures of crops. Here, the inclusion of a network of “mini wild-flower meadows” could replicate the findings of the second study on a wider scale, giving the country bees similar opportunities to those currently available to some of our urban bees.

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