Feral honeybees pose a danger to native bees and the ecosystems that depend on them

3179218B-6138-442F-AA4D3E3EF7E98924By Daniel Rubinoff on January 16, 2018

 

As winter bears down, thoughts of summer and flowers might seem far off, but now is the time to turn our attention to the plight of pollinators and make critical changes to how we manage our environment, and the crops that feed us. Every year the common honeybee, Apis mellifera, is trotted out as a prime example (right up there with monarch butterflies) of what we stand to lose as pollinators disappear. Indeed, the honeybee is arguably humanity’s favorite insect; we’ve been keeping bees with us for at least 6,000 years, and probably far longer.

 

Set loose in American orchards and farm fields, the domesticated honeybee is worth an estimated $3 billion in pollination services. Its light brown and black stripes and veined, gossamer wings symbolize industrious cooperation (see the Utah state seal), sweet goodness (did you know honey can help hear burns?) and amazing insect superpowers (honeybees dance to tell their sisters where the best flowers are).

And yet all its success with humans has made Apis mellifera into something of a bee monster. In North America, it isn’t colony collapse or bee mites or pesticides that is the biggest threat to many of the 4,000 native bee species, it’s the ubiquitous honeybee.

Apis mellifera evolved in Eurasia. Archaeologists have found the chemical signature of beeswax on pottery 9,000 years old. Priests kept these bees in ancient Egypt. The Greeks were first to notice their waggle dance. With our help, honeybees live as far north as Alaska (though they have to be mailed up and reintroduced every spring) and south across the tropics as well. It’s a wildly adaptable species: willing and able to thrive on, and harvest nectar from, almost anything that blooms, everywhere from the deserts around Palm Springs, to the Chesapeake wetlands to the middle of our biggest cities.

Our native North American bees don’t share these qualities. Most of the thousands of species of native bees focus on gathering pollen from a handful of native plant species and make their little homes in dead wood or burrows in the ground. Hidden away, these native bees rear a handful of young, each supplied by their mother (who raises them as a single parent) with their own personal ball of pollen, which is all they need to grow from egg to bee. Many of the natives have very specialized pollinator relationships with a specific species of flowering plant. Or they specialize on visiting only certain groups of flowers that bloom over short seasons.

These native bees have evolved with their partner plants for millennia, making the natives particularly good pollination partners for specific sets of native plants—not only the flowers that decorate our wild lands and forests, but also for native crops like squashes, tomatoes and blueberries. Many bees even time the cycle of their lives according to when their partner plants are in bloom. For example, native squash bees get to work before dawn and have evolved extra-large eyes to see and fly before there’s much light, visiting squash blossoms that open early especially for them; these specialized bees are done for the day before honeybees get going.

But with humans giving honeybees a boost, native bees have fallen on hard times. Outcompeted by the hordes of honeybees pouring from hives all across the country, native bees, with their solitary lifestyles and picky eating habits, have been disappearing for decades. Over 20 years of data now indicate that honeybees deliver a range of negative impacts, including direct competition with more effective native pollinators (not just other bees), and indirect effects like pollinating invasive weeds and facilitating their spread. Honeybees readily escape the hives of beekeepers and go feral, setting up shop on their own, easily invading and dominating a vast array of ecosystems from coast to coast.

It’s these feral honeybees, especially, that pose a challenge to nearly all native pollinators since honeybees forage throughout the growing season for nectar and pollen from a wide array of flowers, building up vast numbers. When honeybee competition reduces the number and diversity of native pollinators, native plants also can suffer since they may receive less efficient pollination.

So what do we do? If we want save these native pollinators, increase biodiversity, and help beekeepers, then feral honeybees need to be controlled. Feral honeybees provide limited value to agriculture (honeybees kept in hives are far more effective) and feral bees maintain diseases that can be transmitted to keeper’s hives, and to native bees. Control should be a win-win for everyone.

Unfortunately, the economic importance of managed honeybees in agriculture and confusion about what happens when they go feral has made the wild ones hard to stop. Our ancient symbiosis with honeybees makes any form of control unpopular with the public. Even environmental organizations like the World Wildlife Fund and the Natural Resources Defense Council use the honeybee as a mascot for conservation, featuring it alongside humpback whales and tigers.

Reinforcing such a misconception has a cost. Equating abundant, invasive, honeybees with endangered species effectively redirects funding that could be spent on the conservation of rare, native, pollinators, undermines support for feral honeybee control, and makes a transition away from our risky dependence on honeybees even harder. We should all be concerned when a non-native insect rightfully recognized as “livestock” by the U.S. Department of Agriculture becomes confounded with icons for the conservation of threatened species.

There is a bright spot—the U.S. Department of Agriculture is finally starting to take the importance of native bees and their pollination services seriously, and will develop a monitoring plan to see how they’re doing. Although the tide is starting to turn as the importance of the many other pollinators is recognized, the honeybee is still dominant. But honeybees are facing a series of recent challenges, which should be cause for revaluating our nearly exclusive relationship. Honeybee colonies are a prime target for specialized predators and parasites that can’t make a living off the handful of individuals that make up the much smaller native bee nests

Perhaps the biggest challenge for the honeybee is colony collapse disorder, a mysterious syndrome that decimates honeybee hives. Native pollinators have their own challenges, but they are not vulnerable to most of the diseases and pests that evolved to take advantage of much larger honeybee colonies. The wise bet would be for us to diversify our pollinator portfolio as soon as possible; right now we rely overwhelmingly on honeybees to serve our pollination needs, leaving us vulnerable to declines in their numbers.

Fortunately, ongoing research shows that, by encouraging a diverse suite of native pollinators in agriculture, we can reduce our dependence on the honeybee and still get the food we need. The native pollinators lead quiet, usually solitary, lives; less flashy than honeybees but often every bit as diligent in their work. For example, those early-rising squash bees move almost four times as much pollen in their namesake crops as honeybees do. While the vast majority of native bees don’t produce honey, and non-bee pollinators don’t at all, the real money is in the pollination services that they provide.

Reducing feral honeybee colonies will help native pollinators, thereby diversifying the team we rely on for food production. Further, because honeybees directly kill more people in the U.S. than any other animal, controlling feral bee colonies will save lives and millions of dollars now spent on the control of unwanted bee infestations, particularly in urban areas. Control of feral bees in nature reserves will bolster native biodiversity, now under siege by the omnipresent honeybee.

Honeybees will always have a crucial place in food production, but the control of feral hives, and a change in our perspective, are important steps towards both increased food security and the preservation of native biodiversity. A reduction in feral honeybee numbers is possible with a concerted effort, and has already been accomplished on a small scale in places like Santa Cruz Island in Channel Islands National Park. More action like this is needed on a much larger scale. Pollinator advocacy is important, but for too long it has been a missed opportunity to engage a national campaign to reconsider our relationship with the honeybee in North America and move our support to the native bee force.

The views expressed are those of the author(s) and are not necessarily those of Scientific American.


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