What if all the Honeybees Died?

Honeybees: Essential to Life on Earth

by Judy Brinkerhoff

“The Earth laughs in flowers” -e.e. cummings

Honeybees pollinate over 100 crops, which is at least half of the crops grown commercially in the USA. In 2006, 50% to 90% of the hives owned and operated by commercial beekeepers were lost. Reasons are multiple, but mites, viruses and diseases are several known factors. Last year, 2007, hives seemed to recover to some degree. However, we must bear in mind that most of our fruit and nut tree crops, many vegetables such as squash, pumpkins and tomatoes, and fodder crops such as clover and alfalfa, depend on honeybee pollination.  Birds, elk, deer, bears and other animals need pollination to ripen the fruits, nuts and seeds they depend on.

Over 600,000 acres of almonds are grown in CA; they are honey bee-pollinated. Half of the commercial hives in the US are moved to CA in mid-February, where two hives per acre pollinate the almonds until mid-March.

Bees pollinate as they gather nectar

Bees pollinate as they gather nectar

Pollination needs are huge. So is it any wonder that researches are trying to determine if pollination can be accomplished by native pollinators? They are finding that blueberries, squash, coffee and cherry tomatoes attract enough native pollinators to produce the fruits. Native bees too are pollinating sunflowers.

The Rominger brothers in the Central Valley of CA are looking to the future for their 3000-acre farm. They grow rice, alfalfa, wheat and sunflowers. To attract native pollinating bees, flies and wasps, they have planted 1.5 mile-long hedgerows, composed of 25 shrubs and trees that bloom in the spring, summer or fall. Further, they have left patches of bare ground throughout the hedgerows to accommodate bees that nest in the ground, as well as placing chunks of rotting wood and wood blocks with holes drilled in them for the insects that nest in wood. It’s not an instant solution, especially for massive crops like almonds, but native pollinators can take the pressure off the honeybees.

And think about this…we humans insist on growing huge monoculture crops, with scarcely a thought of the diversity necessary for sustainable agriculture. Honeybees are not even native to our country. European settlers brought them here in the 1600’s. They are thus particularly susceptible to the type of disaster that could befall them again.

If we don’t know about something, we can’t care about it. Education is one of the ways for humans to ensure that the huge job of pollination continues. We need to learn as much as possible about the role the little individual pollinators play and how we as gardeners can assist in their continuing existence.

Native pollinators are everywhere…in our yards, in the soil, sleeping in blossoms and under leaves. They are in piles of soil or sand, they’re in leaf mulch, under the bark of trees, any place that affords relative protection from weather, predators, and most definitely, human interference. We often interfere inadvertently, by rototilling our soil, shoveling and turning it over, or raking up and disposing of our leaf and yard detritus.

Bumblebees are probably the best known of the native pollinators. They are peaceful, fat and furry and their little pelts collect and distribute lots of pollen as they move from flower to flower. Bumbles do “buzz pollination”; their buzzing vibrates the flower, which releases more pollen. This is perfect for tomato plants; bumblebees are reared to pollinate tomatoes, peppers and strawberries in greenhouses, in fact, they pollinate about 15% of our crops. Bumblebees generate their own heat by buzzing, thus are able to be out and about on cloudy cool days. Honeybees must remain in their hives until they warm up.

Did you know that bumblebees nest in the ground? They dig into the soil or use rodent burrows to feed and raise their little colonies. They die off over the winter, leaving their fertilized queens in the ground to emerge in the spring.

Dr. Gordon Frankie, professor and researcher at UC Berkeley talks about “MULCH MADNESS (MM), a highly promoted eco-friendly method for suppressing weeds, conserving water, and unknowingly discouraging ground-nesting bees! Equally bad for ground nesters is BPI, or better known as Black Plastic Insanity, that is, the laying down of plastic products over bare soil to accomplish the same goals as MM.” Go to: nature.berkeley.edu/urbanbeegardens to learn more about the Urban Bee Garden and their research in Berkeley. They publish an extensive list of native and non-native plants that attract pollinators.

Who would think of leaving a sunny patch of bare, undisturbed soil for ground-nesting pollinators? Perhaps if gardeners knew this not so well known fact, they would do just that. Even a small pile of sand or loose soil will provide the right kind of habitat. Two thirds of solitary bees and flies nest in the ground; the rest nest in some kind of wood. Hollow stems and twigs, beetle tunnels in dead snags, holes of any kind in wood will house a bee or fly nest. Thus, many gardening columnists now advocate leaving lots of dead stems, rotting wood and other debris over the fall and winter for the wood-nesting pollinators.

Beautiful, metallic green sweat bees have a similar life cycle in the ground, as do blue orchard bees.

Some of the most obvious bees, after the bumblebees, are carpenter bees and leafcutter bees. The latter are known by the half-circles they cut into leaves and flower petals. These pieces are carried away to be used as liners for their brood cells, which are usually placed in beetle tunnels in trees. Carpenter bees use wood fibers they scrape from the walls of the tunnel to make dividers for their brood. Mason bees, now better known because many nurseries carry wood blocks drilled out to accommodate the bee nurseries, fill each hole with mud with which they surround their larvae. Ultimately, the larvae make their way out of the cell. Smaller carpenter bees use hollow stems in which to raise their brood. Thus the importance of dead twigs and stems in our gardens. By spring, the insects have left their nests and the remaining debris can then be clipped and composted.

Home on the Honeycomb

Home on the Honeycomb

Other individual bees are abundant in our yards, yet are less seldom seen. These include the yellow-faced bees, plasterer bees, carder bees, digger bees, and cuckoo bees, which lay their eggs in other bees’ nests.

Flies, partly because of their abundance, are also important pollinators. Flower-visiting flies have antennae that are short, fat, and down turned. The main differentiating feature from bees is that flies have only two wings; bees have four, in two pairs of two, often held one under the other. Most bees have specialized parts on their hind legs and abdomen that carry lots of pollen, whereas a fly has less fuzz and bristles that collect pollen grains. Bees require long periods of warmth to forage and breed, whereas the life cycle of flies is quick and therefore more appropriate to cooler weather. Further, flies build no nest, so they have more energy available to feed and mate.

Flower flies, also known as hover flies, or syrphid (Genus Syrphidae) flies, are fairly colorful and obvious to the flower garden observer. Syrphid flies often mimic the coloration and habits of bumblebees. They provide no nest for their larvae, instead laying their eggs right on a flower, where the larvae will hatch and feed on other insects, such as aphids. Others lay their eggs in rotting wood.

A bee fly will remind the discerning watcher of a bumblebee. He is fat and hairy with wings that stick out sideways like a little Cessna airplane. He hovers over a flower and probes with a long proboscis for honey. The larvae of bee flies are parasitic on other insect larvae.

Beetles are pollinators too; in fact, it has been shown through fossil records that beetles and flies were the first pollinators. Nearly 30,000 beetle species exist in North America. Not all visit flowers, however. Several beetle families do and most gardeners have noticed the black and red soldier beetles, which are dining on pollen, flower petals or aphids. Many beetles that visit flowers are metallic or dark or with yellow or red with black markings, but they are often small and go unnoticed by most gardeners. They lay their eggs in a variety of habitats, often in leaf mulch, garden debris, or in rotting wood.

So now what can we as the backyard gardener do to help ensure the existence of native pollinators?

Two actions stand out: 1) provide nesting areas for these little insects and 2) plant a succession of plants that bloom over as many seasons as possible. Native pollinators are often polylectic (there’s a new word for you!), meaning they will go to a variety of flowers. These generalists are flexible and can deal more easily to habitat change and degradation. The “oligolectic” bees collect pollen from a closely related group of plants. Then there are others that gather from one plant only, such as a certain species of cactus.

At any rate, an undisturbed area of garden, pesticide-free, rototilling-free, and sunny will give many insects a place to nest and reproduce. Mason bee blocks, drilled out, hung on a tree or post; rotting logs or snags placed on the ground, will soon be full of insect homes. It’s easy, it takes no effort. So many suburban yards are tidied up to the point where there is literally no place for an insect to nest, hide or mate.

As for plant selection, it’s obvious that any native plant will sustain native insects. However, plants from China, Japan, Africa, South America and other parts of the world have replaced most native plants. We often see insects on them, but it is not known whether they are truly getting sustenance from them. And as birds, hummingbirds, moths and butterflies also do a share of pollination, the more we provide habitat for them the better.

Rather than listing the grasses, vines, annuals, trees, shrubs and perennials that attract pollinators, I recommend three wonderful new books that have appeared in the last year. The books are: “Native Treasures” by Nevin Smith: “California Native Plants for the Garden” by Bornstein, Fross and O’Brien: and “Designing California Native Gardens” by Keator and Middlebrook.

Our local CA Native Plant Society can help. Their site is: cnpsmb.org. So can the Web site mentioned earlier, nature.berkeley.edu/urbanbeegardens. For native wildflowers, look at Judith Warner Lawry’s site at: larnerseeds.com.

Montereybaymastergardeners.org has a beautiful series of newsletters.

The Xerxes Society puts out a fascinating little book called “Pollinator Conservation Handbook”. It tells you everything about native pollinators, with pretty color photos and includes lists of plants, organizations, and associations. Their site is: xerxes.org. They’re out of Portland, and if you really want to help, you can join their membership for as little as $15.00. Educate kids and spread the word…nest sites, food, no pesticides, it’s easy!

For comments or questions, please contact me at: joodbrink@comcast.net. Thank you.

Share with your friends!