Image credit: Stephen Witherden (Westpac Trust Helicopter) via Wikimedia Commons (modified) [CC BY 2.0] (source)

What Does “Save the Bees” Really Mean?

In recent years you have probably heard news reports about the poor health of bees in North America. There have been several competing hypotheses as to the source of the problem — but the best evidence suggests that multiple factors are involved. Some people have pursued political activism to try to address the issue, which might sometimes be a helpful approach. But for many of us, the question becomes this: Other than political activism, what can I personally do to help save the bees?

The first point to clear up is that not all bees are alike. We would never assume that all birds are alike or that all trees are alike. If we wanted to “save the birds”, then we would probably focus on species that we perceive as being at risk (now or in the recent past), such as American eagles, Sandhill cranes, or condors. By the same token, if you would like to help save the bees, then it is quite useful to understand some of the diversity among bees — and to know which ones are most at risk.

The second point to clear up is the distinction between wild bees and commercial beekeeping operations. By analogy, we would certainly be dismayed if an outbreak of avian flu decimated the chickens in a particular state, but we would distinguish between the plight of chicken farms and the plight of wild condors. In other words, we think of these as two distinct issues, even though both issues are worthy of our attention. Likewise, it is helpful to distinguish between the issues facing wild bees and the issues facing beekeeping operations, even though some of the issues overlap. In particular, if we only focus on commercial operations, then we will ignore some of the most serious issues facing our wild, native bees.

Commercial beekeeping operations are based on a single species of bee — Apis mellifera, the European honeybee. This type of bee is important not only for honey production, but also for pollinating several types of food crops, such as almonds. However, this species is not native to North America. On the other hand, there are more than 4000 species of bees that are native here. Like honeybees, many of these natives help to pollinate our crops. Furthermore, many of our native plants have close relationships with the native pollinators — and some depend upon native bees for their survival. It makes sense to give just as much attention (if not more) to the native species of bees, some of which are threatened or endangered.

People sometimes confuse bees with wasps — and indeed, they are related. However, bees differ from wasps in several ways. In particular, bees depend primarily upon pollen and nectar from flowers for their food, while wasps are usually carnivorous, eating insects or spiders. Bees also tend to be fuzzy (which helps to transport pollen), while wasps tend to be fairly smooth. Although some bees look similar to wasps, many bees — such as bumblebees — look quite different from wasps.

The 4000+ species of bees in North America include a range of sizes. At the large end of the scale there are bumblebees and carpenter bees, which most people would easily recognize as being bees. At the small end of the scale are tiny little bees that are smaller than a grain of rice — which most people would not even recognize as bees. Some bees are social and some are solitary. Social bees are like honey bees, living in a colony that includes a queen bee and many worker bees. The workers gather the food while the queen lays the eggs. Solitary bees, as the name implies, live and work as individuals instead of colonies. A solitary bee must do all the key tasks by herself — building the nest, gathering food, and laying eggs.

The primary food of bees is pollen and nectar collected from flowers. Bees, as they travel from flower to flower collecting this food, are very effective at transferring pollen from one flower to another. This pollinating is necessary for the plants to set fruit and bear seeds. Therefore the relationship between bees and certain plants is mutually beneficial, with each depending upon the other for survival. The reason that bees are so good at collecting pollen is that they are covered in hairs, and the pollen sticks to the hairs. In many species of bees, the hairs on the legs are especially good at trapping pollen. Some bees even mix the pollen with nectar to form large pellets which adhere to the legs. Note, however, that the bees do not proactively deposit pollen into any of the flowers they visit. Instead, depositing pollen is simply a beneficial side effect. When the bee visits a flower to collect more pollen, some of the pollen from previous flowers rubs off onto the current flower.

Bees are not the only insects that visit flowers. You have undoubtedly seen butterflies on flowers, and perhaps you have noticed certain kinds of beetles and flies also visiting flowers. All of these insects are capable of transferring pollen between flowers. However, these other insects don’t eat pollen — they are only interested in the nectar — and therefore they don’t intentionally collect pollen. Because they are not adapted for collecting pollen, not much pollen sticks to their bodies. Therefore these other insects tend to be far less efficient pollinators than bees are.

Even among bees, the efficiency of pollen transfer varies. One factor is that some kinds of bees are hairier than others. Another factor is that size sometimes matter — a lot. For example, some flowers are structured such that bees of a certain size will get pollen smeared on their backs. Still another factor is that some bees, especially bumble bees, employ “buzz pollination” to shake the pollen out of the anthers — allowing them to collect a lot more pollen than bees that don’t employ this technique.

Among both bees and flowers, there are “generalists” and “specialists”. If a species of bee is a generalist, then it collects pollen and nectar from a wide variety of flowers. If the bee is a specialist, then it tends to visit only certain kinds of flowers. If a flowering plant is a generalist, then it will probably have a flat flower that is easily accessible to any kind of insect. But if it is a specialist, then the flower will have a special shape, such as a long narrow throat, that only allows certain kinds of insects to reach the nectar and pollen.

In nearly any region of the world, you can find insects and flowers that have “co-evolved” to become specialists together. If you see a flower shaped like a long, narrow tube, then there must an insect with a very long tongue that is capable of reaching the nectar. In other cases, the structure of the flower might be such that only a strong bee is capable of forcing its way inside to reach the pollen and nectar.

In North America, we have a wide variety of such situations, where certain kinds of plants have developed close relationships with specialist pollinators, especially bees. These types of bees are especially efficient at pollinating these specific flowers. For example, blueberries are native to North America, and several species of native “blueberry bees” are especially good at pollinating blueberry flowers.

Several other major crop plants are also native to the Americas, including tomatoes, squashes, pumpkins, beans, cranberries, and eggplants. Our native pollinators tend to be much more efficient at pollinating these flowers than European honeybees are. For example, tomatoes, eggplants, blueberries, and cranberries all require buzz pollination — which native bumblebees do quite well, but honeybees can’t do. Our native squash bees are especially good at pollinating squashes and pumpkins. Even non-native crops, such as almonds, tend to be pollinated by a mix of native bees and European honeybees.

(Note: Pollination is an important issue for crops in which we eat the fruit or seeds of the plant — but it is usually not an issue when we eat the leaves, stems, or roots of the plant. Furthermore, some of our crop plants, such as wheat and corn, are wind pollinated instead of insect pollinated. Therefore insect pollination is important to a lot of different crops, but not to all of our agricultural crops.)

Although native pollinators are quite important for several kinds of food crops, they are equally important for thousands of kinds of native plants that we don’t eat. For example, honeybees are incapable of pollinating our native azaleas, but our native bees are quite good at it.

When we hear stories of “colony collapse syndrome” or other issues affecting bees, the stories often focus exclusively on commercial honeybees. But our native bees are also under stress, and many species are undergoing drastic declines in numbers. This issue is especially acute with some of our bumblebees. A few species have become endangered, and at least one species of bumblebee appears to have gone extinct. As with honeybees, there appears to be several different factors that are contributing to the decline:

  • loss or fragmentation of habitat
  • pesticide use
  • climate change
  • overgrazing
  • competition with honey bees
  • low genetic diversity (a result of low population numbers)
  • non-native pathogens

This raises the question “What can I do locally to help the native bees that live near my community?” The short answer is that you can create bee-friendly places. You can do this on a small scale, such as in a corner of your backyard, or on a larger scale, working to create bee-friendly spaces in parks and other public lands. The two main rules of thumb to keep in mind are 1) to create high-quality “bee habitats” and 2) to avoid the use of insecticides — which of course are designed to kill insects.

Of course, with more than 4000 species of native bees in North America, each with its own preferences, there are several different kinds of bee-friendly habitat that you could potentially create. Furthermore, for any one species of bee, there are three distinct types of habitat that are needed:

1) Foraging habitat

Bees need flowers in order to collect pollen and nectar for food. If you are interested in helping our native bees, then your garden should include some native flowers as part of the mix. Different kinds of flowers are native to different regions of North America, but some good examples are Butterfly Weed (Asclepias tuberosa), Sundial Lupine (Lupinus perennis), Field Thistle (Cirsium discolor), Beebalm (Monarda fistulosa), Showy Goldenrod (Solidago speciosa), Silvery Lupine (Lupinus argenteus), California Poppy (Eschscholzia californica), and Showy Milkweed (Asclepias speciosa). Broader categories of useful flowers include penstemons, lupines, sunflowers, coneflowers, and goldenrod. Furthermore, there are lots of other good choices not mentioned here. Many of our native bees, especially the generalists, can also make use of certain non-native garden plants, including rosemary, oregano, lavender, and red clover.

2) Nesting habitat

Different kinds of bees prefer different kinds of nesting habitat. Some like to make holes in the ground. Others prefer rotten logs or brush piles. Still others like to drill into the hollow stems of plants. And some like to use mud to build their nests. If you have a large property, then an especially helpful strategy is to leave an undisturbed strip of tall grasses and brush near a creek or other source of water. If you have only a backyard to work with, then you can leave a small corner with some bare ground and/or a small brush pile. You can also hang a “bee house” — which might be built from a piece of wood with holes drilled into it, or it might be built from a collection of short, hollow reeds.

3) Overwintering habitat

Among our native social bees, only the young queens survive the winter. Solitary bees must also find a place to overwinter. As winter approaches, the bees seek out a safe place to sleep through the winter. It may be a hole in the ground, such as a rodent hole. It may be a hollow log, a brush pile, under a rock, or in a clump of grass. In a garden it may be a compost pile or an abandoned bird house. If a location has a variety of good nesting spots, then it is also likely to have some good spots for overwintering.

In conclusion, if you are interested in helping to “save the bees”, then give some serious consideration to how you might help our native bees. Plant flowers that native bees enjoy, and create some space for nesting and overwintering habitat. And learn more about the native bees that live in your state, paying special attention to your local bumblebees.

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