In recent years, the question of the extent to which honey bees and wild bees compete with each other has generated increasing interest. In some places, such as in Denmark, the issue has even given rise to a bitter conflict.
The background is that of current threats to pollinating insects. In Sweden, approximately one third of the country’s 300 or so wild bee species are on the endangered list due to shrinking geographical distribution and decreasing population numbers. The primary cause is the intensification of agriculture and forestry and the increasing density of cities, which have made it more difficult for pollinators to find nesting locations and food. Alongside the increase in honey bee-keeping, discussions have begun about the interaction between the managed honey bees and wild bees and whether they compete for food resources.
In a new report on behalf of the Swedish Board of Agriculture, researchers from the Centre for Environmental and Climate Science (CEC) at Lund University have reviewed the relevant existing scientific literature in a European context.
‟We looked at what scientific evidence exists for the notion that competition for food may impact wild bees”, says Sandra Lindström, doctor of agronomy and former researcher at the CEC, now an investigator and biological diversity expert at the Swedish Board of Agriculture..
Visiting the same plants
Based on the literature, the researchers can assert that honey bees and wild bees largely visit the same plant species and thereby risk competing for the same resources. However, what is difficult to establish is what the long-term consequences of this could be on the population – there are simply no studies on this.
‟Competition for resources is common in the ecosystem and has played an important role in the development of species and their niches. However, in combination with human intervention in the habitats and improvements in bee-keeping methods, there is a risk of harm to the wild bees”, says Henrik Smith, professor of zooecology at CEC and at Lund University’s Department of Biology.
More well-designed experiments needed
The researchers also point out that studies must be correctly designed to measure the factors they really aim to investigate – there are very many factors that could affect the distribution and numbers of both wild bee and honey bee populations, which sets high demands on the studies’ ability to determine whether the presence of honey bees really impacts the number of wild bees. That is also why it is difficult to draw far-reaching conclusions from some of the studies already conducted.
“More well-designed experiments are needed to investigate which situations entail a risk of long-term negative impact of honey bees on wild bees”, observes Sandra Lindström.
That said, the researchers nevertheless see a relatively clear consistent trend in the literature that honey bees may negatively impact wild bees.
Conditions for co-existence
“With this compilation of what the science shows us, we want to contribute to creating the conditions for co-existence between bee-keeping and conservation of wild bees. There are many measures that could potentially benefit both honey bees and wild bees”, says Sandra Lindström.
The Swedish Board of Agriculture and Lund University are planning to continue to work together on the issue during 2022.
“We will continue to collaborate to communicate new knowledge about competition between honey bees and wild bees, and to create the conditions for a continued constructive dialogue”, says Thorsten Rahbek Pedersen, manager of the advisory unit on plant nutrients and environment at the Swedish Board of Agriculture.