Threats to Bees
Bee populations are declining world-wide. Although honey bees have garnered much of the press, native bee populations and other pollinators such as butterflies are also declining. These species are vitally important within local ecosystems. Colony Collapse Disorder (CCD) is a major cause of honey bee losses and occurs when adult bees flee the hive leaving the Queen and developing bee brood behind. Without worker bees, the hive is doomed. A number of factors likely contribute to CCD and the decline of bee populations in general. These factors include:
As an insect, honey bees are quite sensitive to most classes of insecticides. Even low doses of these compounds can adversely affect foraging honey bees and therefore the hive itself. Recently, a relatively new class of compounds called the Neonicotinoids were banned in Europe due to their detrimental effects on bee populations.
As open spaces (meadows, fields, and wetlands) are lost or fragmented due to human activities, bees must travel further to forage for pollen and nectar, therefore making it harder to sustain the hive. Successful foraging is particularly critical in the fall when bees need to build-up food stores to sustain the hive through the winter. It is now common for about 50% of all honey bee hives to be lost during the winter months.
Viruses, bacteria, fungi and even other insects can kill bees. The list of bee pathogens is long and growing as we learn more about bee biology. Some of these threats are relatively recent. For instance, Varroa mites (Varroa destructor) are native to Asia but in the 1940’s, were seen in honey bee hives in Africa and Europe. Since this time, Varroa mites have traveled nearly world-wide and are a major threat to bee populations. Even more recently, the Small Hive Beetle (SHB) began infesting honey bee hives in Europe and the Americas. The SHB first appeared in the US in the late 1990’s. This beetle is native to sub-Saharan Africa and thrives in warmer climates. However, SHBs have quickly adapted to colder US environments and can be seen in most states in the North East. Many of these bee pathogens move with bee populations. Because bees are so important for agriculture, bee hives are often transported to fertilize crops. Bees are also transported through the mail as a ‘packet’. The transport of bees facilitates the movement of bee pathogens.
Above right you will see the expanding range and quantity of the SHB in Rhode Island. These increasing numbers are causing contaminated honey and decreases in bee population. The study is continuing to be accessed by RIC students and Dr. Geoff Stilwell at two week intervals throughout June and August.
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