Master Gardeners are known for the research-based, objective information and educational programs that they bring to their communities. In Oregon, where I coordinate the OSU Extension Master Gardener Program, we specifically focus our efforts on sustainable gardening and backyard/community food production. Thus, I thought I would dedicate this blog to a topic that touches on both sustainability and food production: pollinators!
Protected Pollinators = Healthy Harvests
Pollinators play a critical role in both natural and managed ecosystems. The services provided by pollinators range from the ecological (enabling and maximizing flowering plant reproduction, facilitating gene flow and diminishing inbreeding) to the economic (honey production, increased yield and fruit size in agroecosystems). Pollinators are integral to the fruits, vegetables, nuts and seeds that we eat. In fact, some sources estimate that one out of every three bites that we eat directly or indirectly depends upon the activity of pollinators. The ecological and economic importance of pollination emphasizes the merits of pollinator conservation. By protecting pollinators, we can help to facilitate successful crop harvests as well as the propagation of many native plant species.
| Common garden fruits and vegetables that depend upon bee pollination, in order to produce a healthy, high-quality harvest. | ||
| Apples
Apricots Blueberries Cherries |
Cucumbers
Pears Peaches Plums |
Pumpkins
Raspberries Squash Zucchini |
Source: Klein et al. (2007) and Matteson and Langellotto (2009).
What Twas That Buzz?
Although honey bees are perhaps the most famous of our plant pollinators, birds, moths, butterflies, flies, beetles and native bees are also important. In our yards and gardens, we are likely to find many different kinds of native bee. For example, a study of gardens in suburban Westchester County, NY, documented 110 species of bees, 95% of which were native. In New York City neighborhoods in the Bronx and East Harlem, 54 species of bees were found, 81% of which were native. Which bees are you most likely to encounter in your garden? Five major bee families are found in gardens: Apidae (honey bees, bumble bees, and a diverse group of solitary soil-nesting bees), Andrenidae (mining bees), Halictidae (sweat bees), Megachilidae (mason bees and leafcutter bees) and Colletidae (yellow-faced bees or plasterer bees).
Apidae (honey bees, bumble bees, carpenter bees, orchard bees): This large and diverse group of bees includes solitary bees that nest in the ground, eusocial bees that live in hives, as well as many other bee lifestyles! Apid bees tend to be large, hairy, and often have hind legs that act as pollen baskets.
| (Left) Bumble bee (Bombus impatiens) on butterfly weed (Asclepias tuberosa), (middle) honey bee (Apis meliifera) on New York aster (Symphyotrichum novi-belgii) and (right) Bumble bee (Bombus impatiens) on eggplant, showing the pollen basket on the hind leg. All photos were taken in New York City community gardens. |
   |
| Photographer: Kevin C. Matteson
Source: http://www.flickr.com/photos/kevin_matteson |
Andrenidae (Mining Bees): Andrenids are small to medium sized bees that next in the soil. Most andrenids are solitary. Like many apids, andrenids have pollen baskets on their hind legs, but they are usually less hairy than bumble bees.
Halictidae (Sweat Bees): Halictids are generally small bees, some of whom are immediately recognizable by their gorgeous, metallic green or blue-green colors. Most halictids, however, are black or brown. Many are solitary, but a few are communal, some are social, and some are even highly social. They are usually ground nesters, but sometimes nest in rotting wood. Like the apids and andrenids, these bees also carry pollen on their hind legs (pollen baskets).
| (Left) Sweat bee (Lasioglossum (Dialictus) sp.) female on lilly and (right) sweat bee (Halictus ligatus, Family Halictidae) female to the left of a small carpenter bee (Ceratina sp., Family: Apidae) on thistle. Both photos were taken in New York City community gardens. |
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| Photographer: Kevin C. Matteson
Source: http://www.flickr.com/photos/kevin_matteson |
Megachilidae (Leaf Cutter Bees, Mason Bees): The females of these medium-sized, stout bees can be easily recognized by the dense mat of hairs on the underside of their abdomen. This is an adaptation that helps the females to easily gather pollen. Many species in this family use cut leaves to line their nest cells. Mason bees use mud to line the end of their nest cells. Most megachilids are solitary.
| (Left) Wool carder bee (Anthidium manicatum) on lamb’s ear (Stachys byzantine), (middle) leaf cutter bee, showing cut leaf used for nest construction, and (right) leaf cutter bee (Megachile brevis) on butterfly weed (Asclepias tuberosa). All photos were taken in New York City community gardens. |
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| Photographer: Kevin C. Matteson
Source: http://www.flickr.com/photos/kevin_matteson |
Colletidae (Yellow-Faced Bees, Plasterer Bees): These bees are often called the plasterer bees, because they smooth the walls of their nest cells with secretions that dry into a cellophane-like lining. These bees don’t have a pollen-carrying apparatus, like the pollen baskets of apids or the hairy underside of leaf-cutters. Instead, they carry nectar in their gut, and regurgitate it into their nest cells, where their young can feed. Most colletids nest in dead twigs, stems or other cavities. They seem to be extra abundant in urban areas, where they might benefit from artificial cavities, which they use for nest sites (Hernandez et al. 2009).
Bees’ Needs
Even in the most urban of neighborhoods, gardeners can take advantage of the services that bees offer to vegetable gardens, fruit trees and other flowering plants. Even better – there are a few simple things that gardeners can do, in order to help attract honey bees and native bees to their garden, and to help conserve native bees in our environment.
Choose Bee-Friendly Plants
Bees are excellent pollinators because they spend most of their adult lives collecting pollen and nectar to feed to their young. Bees are most attracted to flowers that are offer them nectar and pollen, on which they can feed themselves and their young. Yellows, purples, blue and white flowers are quite popular with bees. Plan to have flowers in bloom all season long. This will especially benefit the andrenid bees, which tend to come out in the early spring, when not much is in bloom. Having blooms all season long will also benefit the eusocial bumble bees and honey bees, that typically rear multiple generations within a single season. Planting flowers in clumps will attract more pollinators than having plants scattered, individually, throughout your garden. Clumped flowers deliver a big floral display that is like a neon sign to bees that says ‘Good Eats Can Be Found, HERE!’.
| Plants for Bees (taken from: Shepherd, M. Plants for Native Bees in North America. Invertebrate Conservation Fact Sheet. The Xerces Society. Visit www.xerces.org for more information, and for region-specific plant lists.) | ||
| Aster
(Symphoyotrichum) |
Goldenrod
(Solidago) |
Rabbitbrush
(Chrysothamnus) |
| Buckwheat
(Erigonum) |
Joe-pye weed
(Eupatorium) |
Rhododendron
(Rhododendron) |
| Bee balm
(Monarda) |
Lupine
(Lupinus) |
Sage
(Salvia) |
| Blazing star
(Liatris) |
Milkweed
(Asclepias) |
Scorpion Weed
(Phacelia) |
| Ceanothus
(Ceanothus) |
Oregon Grape
(Mahonia) |
Snowberry
(Symphoricarpos) |
| Creosote bush
(Larrea) |
Penstemon
(Penstemon) |
Spider Wort
(Tradescantia) |
| Giant hyssop
(Agastache) |
Prairie clover
(Dalea) |
Sunflower
(Helianthus) |
| Purple Coneflower
(Echinacea) |
Willow
(Salix) |
|
Don’t Forget the Nest Sites!
Of course bees like to eat, but they also need to rest. Providing them with flowers from which they can sip is only half of the picture to having a garden full of pollinators.
Most bees nest in the ground, and thus need easy access to soil in which they can dig and construct their nests. What does this mean for gardeners? You can rest easy knowing that the bare patch of garden that has been bothering you is heaven for ground-nesting bees. Weigh the benefits that you might get, in terms of weed suppression, from mulch with the negative impact it will have on ground-nesting bees. You might even consider building a small sand pit, or placing a small sand pile in your garden, to benefit the bees.
Other bees, like the colletids, are cavity nesters. Tolerate old logs, stumps and snags, and you might benefit from more bees in your garden. Create stem or tube bundles from bamboo or reeds. You can even build or purchase nesting blocks for bees. Plans can be found online (http://www.xerces.org/wp-content/uploads/2009/11/tunnel-nest-management-xerces-society.pdf).
Spread the Word – Pollinators are the Bees’ Knees!
However you choose to conserve and enjoy bees in your yard, make sure that your clients know that not all insects are bad. (As a Master Gardener, perhaps you have met a client or two who hates ALL insects, no exceptions?) Of course, some insects, like the bees that pollinate our gardens and our crops, are essential to the life we enjoy. Afterall, I couldn’t enjoy my chocolate bar with almonds without pollinators. Bees pollinate almonds. Flies pollinate cocoa. No chocolate almond bars without pollinators? Now THAT would be a tragedy in my world!
References
Fetridge, E., J. S. Ascher and G. A. Langellotto. 2008. The bee fauna of residential gardens in a suburb of New York City (Hymenoptera: Apoidea). Annals of the Entomological Society of America. 101: 1067-1077.
Klein, A., B.E. Vaissière, J.H. Cane, I. Steffan-Dewenter, S.A. Cunningham, C. Kremen, and T. Tscharntke. 2007. Importance of pollinators in changing landscapes for world crops. Proceedings: Biological Sciences 274:303-313.
Hernandez, J.L. et al. 2009. Ecology of urban bees: A review of current knowledge and directions for future study. Cities and the Environment. 2(1):article 3, 15 pp. http://escholarship.bc.edu/cate/vol2/iss1/3 .
Matteson, K.C. and Langellotto, G.A. 2009. Bumble Bee Abundance in New York City Community Gardens: Implications for Urban Agriculture. Cities and the Environment. 2(1):article 5, 12 pp. http://escholarship.bc.edu/cate/vol2/iss1/5.
Matteson, K. C., J. S. Ascher and G. A. Langellotto. 2008. Richness and composition of the bee fauna of urban gardens in New York City (Hymenoptera: Apoidea). Annals of the Entomological Society of America. 101: 140-150.
Hi, I’m a Minnesota MG and really enjoyed your article. Do you happen to have it in a pdf?
Hi Karin, I sent you a pdf via email. Please let me know if it was not received.
Do Carpenter Bees fall into the category of pollinators? Here in south alabama they are considered quite a distructive pest.
All bees are pollinators, but some (such as carpenter bees and leaf cutter bees) can be pests.
As pollinators, carpenter bees are generalist in the garden. They will visit many different types of flowers to gather nectar and pollen, rather than restricting their activity to only a few floral types. Because they are ‘buzz pollinators’ (i.e. they use sonic waves from their wing flapping to dislodge pollen from floral anthers), they’re considered especially good pollinators of tomatoes, eggplant and other hard to pollinate flowers.
As pests, carpenter bees tunnel into wood (usually, bare, weathered and/or unpainted), and can leave quite a bit of damage (visit this great site at Clemson Cooperative Extension, for a nice photo: http://www.clemson.edu/extension/hgic/tyk/2009/tyk06.html). Clemson Cooperative Extension even has a nice video on the subject (http://www.clemson.edu/extension/hgic/videos_posters/videos/carpenter_bees.html).
I enjoyed your article on garden bees as pollinators. My husband and I have thought about getting started with some honey bees, but are not sure if we have enough plants and flowers to sustain them.
Hi Wilma.
Honey bees hives are successfully kept on New York City rooftops (http://www.nytimes.com/2010/03/15/science/earth/15bees.html). Thus, I’m sure you have enough forage for your bees. Honey bees regularly forage up to 1 mile from their nest . . . often 2 miles . . . rarely more than 2 miles. Having to fly far for nectar and pollen wastes more energy than they gain from the far away flowers! Of course, you can always plant more bee-friendly plants in your yard, so that they can successfully forage closer to home.
In the off-season, most bee keepers (even those in areas with lots of flowering plants) have to ‘feed’ their hives, as there isn’t much in bloom in the late fall through early spring.
Thus, don’t let the current palette of plants in your backyard deter you from keeping honey bees. If your neighborhood offers good forage, they will be happy.
Gail – Good job! Since my wife and I are amateur beekeepers – hobby only – your title caught my interest. Too many folks don’t realize the importance of our busy insects at helping to sustain our lives. There is no way that we could ever replace the “free work” these little friends do for our welfare – of course, they don’t know that they are doing that for us – and it is probably just as well that they didn’t!
All bees are gifted naturally when it comes to finding their own food sources. However, there are times when help is needed if natural food sources are low. Experienced beekeepers know that without proper feeding honeybees are unable to sustain their young, their energy levels needed to work dwindle and their continued survival is severely compromised. We can all help our bees by planting many sources of nectar but interestingly they love Blue and Yellow flowers in particular. There are many species of flowers with these coloured blooms and it is really nice if you leave a bowl of fresh water each day for them nearby. Bees drink too! They will reward you with a beautiful garden and you will be rewarded by saving them. http://www.health-benefits-of-honey.com/honeybees.html
Great article, will be rethinking my garden to get more bees in there!