Do Domestic Honeybees Impact Native Bee Populations?

Do Domestic Honeybees Impact Native Bee Populations?

If you ask any beekeeper whether they feel their efforts are environmentally beneficial, you’re likely to get a rousing “Yes!” Of course, beekeeping benefits the environment. Pollination, baby! 

Therefore, it’s jarring to be faced with an unpleasant paradox: By keeping domestic honeybees, beekeepers may be competing with wild bees. 

There is hardly a person on the planet who doesn’t understand bees’ critical role in pollination. Honeybees have enormous environmental and economic importance. It is estimated they pollinate one-third of our food supply. 

But honeybees are not native to North America, a fact that surprises many. Instead, seven non-native bees were introduced during colonial times for their wax, honey, and pollination. 

North America has over 4,000 native species of bees, including mason bees, bumblebees, sweat bees, and leafcutter bees. The difference is that these species are generally solitary, not eusocial (living in colonies), and therefore harder to utilize commercially. Solitary bees are “gentle, easy to attract, and are very efficient pollinators known for their energetic nectar harvesting techniques,” in the words of Alexandra Burton. By contrast, honeybees are territorial since they have a hive to protect. 

Studies have shown that solitary native bees will avoid areas with heavy concentrations of honeybees (to avoid territorial aggression).

The good news is wild bees and honeybees can coexist very well. Honeybees are generalists — they will forage across a wide range of plants, both native and exotic. Native bees, however, are often species-specific with what plants they visit. (Short-bodied bees, for example, will avoid tube-shaped flowers, while long-bodied bees prefer them.) Since they tend to gravitate toward slightly different foraging areas, the presence of honeybees does not necessarily exclude native bees, especially in areas designed to attract both. In this regard, native and non-native bees do not heavily compete against each other — assuming there is enough variation in vegetation to provide for both their needs. 

Studies have shown that solitary native bees will avoid areas with heavy concentrations of honeybees (to avoid territorial aggression). Wild bees and honeybees favor slightly different foraging opportunities, so planting vegetation to attract both will allow the species to coexist and maximize pollination. 

So, what dangers do honeybees pose to native bee populations? There are two issues: (1) diseases and parasites, and (2) competition on public lands. 

Diseases and Parasites 

When honeybees land on flowers, they leave behind feces which can host viruses, bacteria, or other pathogens which wild bees can then pick up. An example is the Deformed Wing Virus (DWV), affecting both domestic and wild species. While the extent and impact of DWV on wild bee populations are still being determined, there are concerns about population decreases. Another concern are the Nosema fungal pathogens: common in honeybee colonies and can be transmitted to certain species of native bees. 

Environmental pressures such as disease, pesticide exposure, and habitat fragmentation or loss affect native and non-native bee populations, but how these pressures impact different species is more nuanced and complicated. One bright spot is both native bees and honeybees are showing evidence of thriving in urban landscapes. Honeybees favor gardens (residential or commercial), while solitary bees prefer green spaces and more open areas (such as parks with trees). Both these components are abundant in urban areas. 

By comparison, homogenous environments (such as stretches of identical suburban homes) favor the generalists (honeybees) to the detriment of the specialists (native bees) — something to keep in mind with suburban landscaping efforts. To optimally attract both honeybees and solitary bees, experts suggest planting areas with 75% native flowering plants and 25% non-native (but non-invasive) flowering plants. This kind of diversity will provide overlapping bloom times and variations in nectar and pollen accessibility. 

All bees, however, are adversely affected by pesticides, which is why minimizing their usage will help both native and non-native populations. 

None of this information is meant to imply backyard beekeepers should not keep hives. Instead, it’s meant to encourage small-scale apiaries to diversify their vegetation to attract both kinds of pollinators. 

Public Lands 

Commercial apiaries face a different battle. Some scientists argue commercial apiaries should not place beehives on public lands or undisturbed places where wild bee populations are both critical and specialized. Studies show wild bees in undisturbed areas consume up to 95% of available local pollen. By introducing commercial hives into these sensitive areas, honeybees may indeed compete with the native populations of specialized foragers. 

Beehives in the mountains

“Honeybees are super-foraging machines, and they are taking the pollen out of the mouths of other bees and other pollinators,” said Stephen Buchmann, an adjunct professor at the University of Arizona and a pollination ecologist specializing in bees. 

His concerns are valid. Of 72 studies conducted to assess competition between wild and managed bees, about half found honeybees negatively impacted wild pollinators by dominating limited nectar resources. The remaining studies indicated either neutral or positive impact. 

Understandably, claims of detrimental impacts of honeybees often fall on deaf ears of apiarists, businesses, and politicians. Honeybees have a staggering $15 billion economic impact in North America, and who wants to imply sweet little honeybees can be damaging? But many advocating on behalf of wild bee populations argue that no amount of honeybee hives is safe on public lands. 

One study “found a single honeybee hive extracts enough pollen in one month to rear 33,000 native bees,” reports journalist Jennifer Oldham. “If this figure is multiplied across apiaries with 100 hives, such as what is permitted in some national forests, entomologists say it could imperil the ability of wild pollinators to sustain their populations.” 

Yet commercial apiaries face habitat loss as well. Often their previous grounds are taken over by subdivisions or other urban growth. Even formerly diverse farmland is often converted into monocrops that don’t require insect pollinators (such as corn), which is why many apiaries lobby to use public lands for their hives. “We are running out of land,” said one fourth-generation beekeeper. “We’ve reached the carrying capacity for managed beehives in the U.S. — without access to public lands, our [honeybee] livestock could be in peril.” 

Commercial apiaries are often tasked with beginning each season with double the number of hives in anticipation of harrowing losses (up to 44%) while servicing an accelerating proportion of crops dependent on pollinators. They’re caught between a rock and a hard place. 

There is no easy answer to the question of whether beekeeping is bad for native pollinators. For the backyard beekeeper, though, the best thing you can do is encourage both types of pollinators by planting suitable vegetation and providing housing options for native bees. 

Originally published in the December2021/January 2022 issue of Backyard Beekeeping and regularly vetted for accuracy.

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