The Man-Made Reason Why Honeybees Are Dying

beehives

Story at-a-glance -

  • The Varroa mite, a parasitic mite that feeds on the blood of adult and developing honeybees, serves as a vector for deformed wing virus (DWV)
  • DWV a major threat to honeybees and it’s now distributed among honeybees worldwide
  • It’s thought that the virus spread from a common source, the European honeybee, as a result of humans moving honeybee colonies around the globe

By Dr. Becker

Bee populations are declining across the globe, and each premature bee death matters. Every day, one bee colony may pollinate 300 million flowers, which explains why 70 of the top 100 human food crops, which provide 90 percent of the world’s nutrition, according to Greenpeace, depend on bees for pollination.1

There are many theories as to what’s killing the bees, some more likely than others. Pesticides, particularly neonicotinoids, have been implicated in both commercially bred species like honeybees, bumblebees and wild species.

Recent research has shown that, overall, about 50 percent of the total decline in wild bees was linked to the pesticides.2 Another threat to bees is the Varroa mite, a parasitic mite that feeds on the blood of adult and developing honeybees.

Not only does this weaken the bee and shorten its life, but Varroa mites also act as vectors for deformed wing virus (DWV).

Deformed Wing Virus Is Killing Off Bees, and Humans Are Fueling Its Spread

If a developing bee is infected with DWV, it may suffer from wing deformities that make it unable to fly. As a result, the bee dies. It’s long been assumed that DWV is relatively harmless to the overall health status of beehives. For instance, in 2009 researchers wrote in Applied and Environmental Microbiology:3

“… DWVs play a secondary role in the causes of honeybee disease compared to their parasitic and bacterial counterparts as the viruses routinely reside at low levels in colonies, with symptomatic infections being rare.”

Further investigation revealed, however, that DWV may actually be a major factor in colony losses that occur over winter.4 More recently, it was noted that not only is DWV a major threat to the world’s honeybees, but it’s now distributed among honeybees worldwide.

It’s thought that the virus spread from a common source, the European honeybee, as a result of humans moving honeybee colonies around the globe.

The Man-Made Spread of Deadly Deformed Wing Virus

The concerning finding was revealed after researchers analyzed genetic samples from honeybees and Varroa mites in 17 countries.

The epidemic spread of DWV appeared to start with European honeybees then spread to North America, New Zealand and other countries. According to the study, which was published in the journal Science:5

DWV exhibits epidemic growth and transmission that is predominantly mediated by European and North American honeybee populations and driven by trade and movement of honeybee colonies.

DWV is now an important reemerging pathogen of honeybees, which are undergoing a worldwide manmade epidemic fueled by the direct transmission route that the Varroa mite provides.”

In order to stop DWV from wiping out more hives, there should be mandatory health screenings on imported honeybees in order to stop the Varroa mite from infecting the few remaining mite-free regions.

Why Are Bees Moved Across Countries?

Honeybees are necessary to pollinate many large-scale agricultural crops, including almonds, berries and apples. However, there aren’t enough wild bees present to pollinate such large expanses of crops. As a result, beekeepers transport their colonies to the crops that need them for pollination.

The colonies, which are made up of so-called migratory bees, may be moved on a regional or national scale, and some commercial beekeepers transport bee colonies for many months out of the year. As written in the journal Scientific Reports:6

“Honey bees (Apis mellifera) are the most economically important pollinators in North America and are crucial for sustaining production in many agroecosystems.

Honey bee colonies are composed of tens of thousands of individuals, which allows them to pollinate crops effectively over a large geographic area, particularly with the assistance of beekeepers who transport colonies for pollination services.”

Such transportation is necessary to keep up with the large-scale agriculture common in the 21st century, but it comes with serious risks to the bees, not the least of which is apparently the spread of Varroa mites and deadly DWV.

Migratory Bees Face Significant Health Risks

In a comprehensive study on the impacts of transporting honeybee colonies for commercial purposes, serious concerns were revealed.

The researchers compared bees from commercial and experimental migratory beekeeping operations to those from stationary colonies. Compared to the stationary bees, the migratory bees had a significant decrease in lifespan and increased levels of oxidative damage.7 Other risks include:

  • Increased exposure to pesticides and pathogens
  • Limited access to diversified pollen sources
  • Forcing foraging bees to re-learn and re-assess their environmental surroundings

As noted in Scientific Reports:8

The assumption, therefore, is that factors associated with migratory beekeeping operations overwhelm bees and induce a stress response, ultimately contributing to increased colony losses and susceptibility to disease, parasites and syndrome-like effects such as Colony Collapse Disorder (CCD).”

Simple Ways You Can Help Save Bees

Global efforts will be needed to stop the spread of DWV as well as improve the health of migratory bees. A return to small-scale organic farming would help, as diverse, natural landscapes allow bees to flourish and naturally pollinate small-scale crops nearby.

You can support this movement by purchasing organic and locally grown foods while also making your backyard more hospitable to bees of all kinds. Native plants that provide nectar and larval food for pollinators make excellent additions. If you think you don’t have room, consider putting in flowerbeds instead of lawn.

You can also install houses for native bees. While honeybees live in hives, some bees nest underground and others live in natural cavities, like inside a hollow reed. You can create nesting blocks easily by drilling different sized holes into a block of untreated wood.9

Also, reduce or eliminate the use of pesticides and other chemicals (like lawn care chemicals) around your home. Finally, make a point to support local honeybee hives. Buy local, raw honey, for instance, or other products made with locally sourced bee products. Many small organic farmers also raise bees, so buying from these farmers will help secure the bees’ future.