Where have all the flowers gone? A story about the bees.
If we are dreaming of summer during these last rainy winter days we may picture a field of flowers and the sweet smell of it. But what if this picture suddenly disappears? What if the flowers in this world suddenly vanish and what’s left is grey wasteland? Could be only science fiction, or how far are we away from such a scenario? Well, here it comes: our honey bees are endangered! What do now the bees have to do with the flowers? It’s general knowledge that flowers need to be fertilised to produce offspring; a process that starts with the pollination of the flower. For many plants, including our flowers, pollination is dependent on insects that carry the pollen with them when they fly from flower to flower to get the nectar. One of the most important pollinators for this system is our honey bee.
Bees are important pollinators of the flowers. (Picture via Pixabay).
Threats to the honey bee
Worldwide the bee colonies have been collapsing over the last 10 years. It was in the winter of 2006-2007 when US beekeepers were suddenly observing an unusual high loss of bees in their hives, a phenomenon that is termed colony collapse disorder. It continued with reported bee colony collapses in Europe and Japan. Beekeepers were first puzzled about this phenomenon but research over the last decade gives us a multitude of answers why our bees are dying and most importantly how we hopefully can prevent it. A recently published review summarises the stress factors generated by industry and modern agriculture that are threatening our bees such as pesticides, pollutants and malnutrition due to monocultures and low plant diversity, which are building the basis for bee food resources. Bees are especially vulnerable to these stressors as it was found that they have effects on the brain of the bee. To navigate from flower to flower and finding back to the nest cognitive processes such as learning and memorising are essential for the bees. These cognitive processes are disturbed by pesticides, heavy metals, diet restriction and viruses leading to changes of the behaviour and disorientation of the bees. However, besides the industrial and agricultural caused threats the probably worst enemy of the insect was found – VARROA DESTRUCTOR.
The bees’ enemy
Varroa destructor is a mite that has its ancestors in North Asia where it was a parasite of the Asian honey bee from where it moved to establish itself in bee colonies in Europe, the US, southeast Asia, South America and Africa. In 2000 the mite made its way to New Zealand. Australia since then was bearing up against the bee’s enemy and thought to be free of the varroa mite, however, alerts of the last months raised again the fear that the bee killer might has made it to the last preserved territory with detections of mites in Asian bee colonies in Townsville (June 2017). The varroa mite is the bee’s enemy as it is not only an external parasite of the bee but is further lowering the immune system of the insect, making it more prone to get infected by viruses. In an infected hive the varroa mite is primarily feeding on the haemolymph (the “blood”) of the bee larvae but can be also found on adult insects with whom they can hitchhike and spread to other hives.
The varroa mite can travel on the bee to new destinations. (Picture via Pixabay).
Thankfully some research has been done on the effects of varroa mites on our bee colonies and how to arm our bees against this enemy. A lot of research therefore focuses on how to eliminate the varroa mite either in a physical way or by chemical treatments against the mites. A different approach is followed up by an Australian scientist at the University of Sydney where not the mite itself is addressed but the diseases that it brings. In this approach, a bacterium with the name Wolbachia is injected into the bee eggs. Wolbachia is a bacterium that lives in symbioses inside a lot of insects but most importantly it was found that some of its benefits are to provide virus resistance in some insects such as flies and mosquitos. Having these attributes, Wolbachia is already used in mosquitos to prevent transmission of Dengue fever. It must be awaited if this approach works out to better protect our bees but it is good to know that there are Scientists that are fighting for the wellbeing and maintenance of our bees.