Isla Stubbs takes a look into how honey bees are threatening other wild bees and pollinators and discusses what can be done to prevent this threat.
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Bees are in decline; we all know it when we see “Save the bees” slogans plastered everywhere. As a result, beekeeping has boomed, particularly in urban areas, in an attempt to “save the bees”. However, what these campaigns don’t tell you is that honeybee populations are actually on an exponential increase. What many people don’t know is that there is only 1 species of honeybee and they are actually thought to be a contributing factor to the decline of the other 250+ species of bees in the U.K.
Much like the well-known ‘grey squirrels versus red squirrels’ competition, honey bees are strong and resilient and are dominating the pollinator population, out-competing wild pollinators and spreading diseases to other bee species. A literature review conducted in 2017, examining the impact managed honeybees have on wild bee populations, has shown that managed bees negatively affect, or have the potential to negatively affect, wild bees through competition, changes in plant communities, or transmission of pathogens.
Why are wild pollinators so important?
Having biodiversity among our pollinators is extremely important for us to utilise the ecosystem services they provide, mainly food production. Managed honeybee hives are only responsible for approximately 5-15% of the U.K.’s insect-pollinated crops, with the other 85-95% relying on wild bees, moths, butterflies, hoverflies and more. Wild bees (which includes solitary and bumble) can be twice as effective in pollinating crops such as oilseed rape, coffee, onions, almonds, tomatoes and strawberries when compared to honeybees. Honey bees aren’t physically big enough to pollinate tomatoes; these fruits require large bumble bees for pollination.
Honey bees are very efficient gatherers, which actually makes more inefficient pollinators. They are more likely to hold on to the pollen they collect as they have special sacks on their hind legs to store it, unlike other bee species which tend to drop a lot of pollen on their visits as they rely on the pollen to stick to the hairs on their abdomen. Dropping pollen on their journeys provides immense amounts of pollination, and it is thought that a single red mason bee pollinates the equivalent to 120 honeybees. Therefore, our current reliance on honeybees is unsustainable and relying so heavily on this single species is likely to cause problems when diseases appear.
Wild bees in particular are very important, as some species (such as, the buff-tailed bumblebee) have the ability to “buzz pollinate”. Some flower species hold their pollen more firmly than others, and the vibrations during buzz pollination dislodges and releases this pollen. Some species of fruits can only be pollinated using this technique, including blueberries and cranberries. With the global population predicted to reach over 9 billion by 2050, it is essential to look after all of our pollinators in order to maintain high levels of food production.
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How do honey bees threaten wild bees and other pollinators?
Some studies have shown that species of wild bee species (mainly bumblebees) have contracted diseases from managed honeybee populations. Deformed wing virus and the fungal parasite Nosma ceranae are the most common honey bee diseases that have also been detected amongst adult bumblebees. This is because infected honeybees leave behind viral or fungal particles on flowers, which are then picked up by the wild bees when they visit. This is where environmentalists can work alongside beekeepers to learn to recognise symptoms of diseases quickly and work on treatment and prevention in managed hives, which will in turn reduce disease in wild bee populations; a win for everyone!
The uses of pesticides, herbicides and fungicides all have effects on managed and wild bee populations, increasing mortality or increasing susceptibility to disease. However, wild bees are likely to be more vulnerable than honeybees to these agrochemicals. Managed honey bee hives have 80,000+ individual bees and this can create a buffering effect when exposed to these harmful chemicals, and it is easier as a large colony to develop resistance and then become even more dominating in the community. Solitary bees don’t have this power and are likely to die out when exposed to agrochemicals.
Part of the wider literature review mentioned earlier, examining the impacts honeybees have on wild bee populations focused partly on competition. In wildflower habitats rich with pollen and nectar, it is likely that there is no competition between these different pollinators. However, as beekeeping continues to grow more popular in urban landscapes where these flower-rich habitats have been lost, there becomes a lack of food available for all bee species. There is evidence to support the hypothesis that when social bumblebees are exposed to competition from honeybees, there are high levels of nectar scarcity, and foragers are forced to focus on nectar collection over pollen. This can reduce rates of larval production, as well as reduce pollination of plant communities.
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