Why A Post About Native Bees?
Winter's moving in, flowers are done blooming (at least in northern areas), so why think about bees and pollination right now? Well, lots of reasons! For some of us, seed catalogs are arriving and we're starting to plan next year's gardens. For all of us, almost every bite of food we take is made possible by native bees and honey bees. Their fate and ours are intimately connected. Bees are colorful and interesting, and knowing more about them enhances our perspective on the world at large. It can change how we see the landscapes around us and how we think about what to eat and plant. This post gives an introduction to native bees, honey bees, and threats faced especially by native bees, who are unsung heroes of the flowering and fruiting landscape. Our next post describes actions we can take to help these small and powerful beings who so much depends on.
An Introduction to Native Bees and Honey Bees
Bees evolved from wasps as flowering plants began to spread across the land. Whereas wasps are carnivorous, bees evolved to eat plant pollen and nectar. Co-evolution of plants and pollinators led to the expansion of bee and flowering plant species. This dance of give and take between plants and bees continues. Native bees are species that evolved on this land, beginning some 125 million years ago. There are about 4,000 native bee species in the U.S., and many aren't yet named or described.
There's a huge amount of diversity among those bee species. Some are tiny, such as Perdita minima, a bees that's less than 2mm long, nests in sandy desert soils, and pollinates small desert flowers. Carpenter bees are the largest native bees in the U.S (up to about an inch). They dine on a variety of flower types (including vegetable flowers) and can live up to a few years.
Some native bees are specialists that feed on a single genus or species of flower. Others are generalists and can feed on various flower types. If you grow squash, pay attention to the flowers – you're likely to see squash bees in the blossoms. Most native bees are solitary, meaning they nest alone in underground tunnels or in plant stems or holes in trees and logs. But some, such as bumble bees, live in small colonies. All bees share an important characteristic: they feed only on the nectar and pollen of flowering plants. On a world-wide basis, native bees pollinate about 80% of flowering plants.
Native bees are found in every ecosystem that contains flowering plants, from forests to deserts, mountains, wetlands and tundra. Bees themselves are an important food source for other animals. Birds, other insects, spiders, amphibians and mammals eat bees and bee larvae. Bees ensure that plants produce fruit and seeds; this makes them fundamentally important to the entire web of life.
The "European" or "Western" honeybee, Apis mellifera, is native to Europe, the Middle East and Africa. The honeybee was introduced into the present-day U.S. by European colonists in the early 1600s. Honeybees live in large colonies with a division of labor that includes up to 65,000 worker bees, hundreds of drones, one queen, plus thousands of larvae, pupae and eggs. Worker bees collect nectar and pollen; they feed the pollen to larval bees, and they make the nectar into honey. Honey is the bees' main food source and is what they survive on over the winter.
The average recorded flight distance of honeybees is further than that of many native bees. This makes honeybees capable of gathering nectar and pollen from greater distances than many native bees can travel. Honeybees are generalist pollinators that can feed on many types of flowering plants. While honeybees often outcompete native bees for nectar and pollen, they're less effective at pollinating many flowers compared to native bees.
Challenges for Native Bees
Native bees face many challenges. A 2017 report by the Center for Biological Diversity found that about a quarter of North American and Hawaiian native bee species are "imperiled." Further, about 50% of native bees were found to be in decline. Some of the major threats include:
As industrial foodscapes move across the landscape, natural habitats are replaced with mechanically managed, chemically treated crops. Native pollinators cannot thrive in these landscapes because of chemical toxins, mechanical disturbance, inadequate nutrition and lack of nesting sites. To make industrial agriculture "work," honeybees are brought in by truck to pollinate monoculture crops. These itinerant bees feed during the day and return to the safety of their hives at night.
When one crop is done flowering, the bees are trucked off to another area with a different crop in need of pollination. This lifestyle is hard on honeybees too; industrial agriculture is a major factor in honeybee colony loss.
Honeybees: Some Bitter Facts
Honeybees still need to eat after their work is done on commercial crops. As more natural areas are plowed under and paved over, large-scale bee farmers are losing foraging areas to development. Now, honeybees are being moved onto public lands to recover from their work on industrial farms. This creates intense competition for food with native bees and exposes native bees to introduced diseases.
Honeybees are "foraging machines" that "can very quickly take down the standing stock of pollen and nectar," says bee specialist Stephen Buchmann of the University of Arizona. Honey bees are being placed in national forests throughout the U.S. without environmental assessments of their effects on native pollinators and ecosystems.
Bee-keeping is a hobby and business that many people enjoy and profit from. And many non-beekeepers, including me, love a nice dollop of local honey. But there's a bitter side to bee-keeping. Introducing honeybees into the neighborhood creates competition for food with native bees, and honeybees can spread diseases and parasites to native bees. If native bee populations decline, entire ecosystems and food webs will change.
Pesticides and Suburban Sprawl
In urban and suburban areas, bee habitat is fragmented by roads, buildings and other structures. The American obsession with tidy green lawns leads to heavy use of toxic chemicals around homes and yards. Non-diverse & heavily managed landscaping further starves insects, birds and other creatures of needed food.
Fortunately, awareness is growing and more of us are tuning in to the importance and beauty of pollinators and native plants. The problems and challenges described here can also point towards solutions. And what better time to contribute to the solutions than now?! So turn the page, so to speak, and let's dive in to…