Written by Rhonda Kranz
Revised June 2011


Many people think only of allergies when they hear the word pollen, but pollen plays a vital role in the health of our environment, in agriculture, and in our aesthetic enjoyment of the world. Pollination is the transfer of pollen grains to fertilize the ovules - eggs - of flowers to produce fruit and seed. While some plants are self or wind pollinated, more than 70% of the world's flowering plants rely on animals to transport pollen for them and more than 30% of the human diet is dependent on pollinators.

Pollinators come in all shapes and sizes. More than 200,000 invertebrates and 2,000 vertebrates serve as pollinators worldwide including insects, birds, mammals, and even reptiles. The co-evolution of these pollinators and their host plants is one of nature's unique solutions to the dilemma of sexual reproduction.

Test your knowledge about pollinators with our Pollination Quiz

Learn More

What is Pollination? Who are the Pollinators?
Pollinators in Danger Honeybees and Colony Collapse Disorder
Pollinators in Sligo Creek and our Neighborhoods What You Can Do To Protect Pollinators
Creating Pollinator Friendly Gardens National Pollinator Week
Pollinator Resources and Educational Materials Pollination Quiz
Pollination Syndrome What You Can Do To Protect Pollinators Fact Sheet
Pollination in Poetry and Prose

Pollinators in Sligo Creek and our Neighborhoods

MD, VA, and DC are wonderful places to see pollinators in action. Just walk around the neighborhood and look for butterflies, bees, moths, and flies on the flowers of familiar trees such as black cherry, dogwood, and magnolia. Peek in neighborhood yards to observe azaleas, milkweed, and those beautiful little violets that pop up seemingly out of nowhere. In vegetable gardens, watch bees and other insects provide free gardening services as they pollinate squash, melons, tomatoes, and beans. Take a stroll along Sligo or Rock Creek parks and watch what happens when Spring Beauty, Jack-in-the-Pulpit, and others are in bloom. You don't need to know the names of any of these plants or their pollinators to just enjoy the show.

What is Pollination?

Pollination is central to successful reproduction in most plants. It is the transfer of pollen grains from the anthers of one flower to the stigmas of the same or another flower. Movement of pollen via wind is a common strategy and in our region we helplessly encounter this each spring as large quantities of oak and pine pollen move through the air in the hopes that some of it will land on flowers of the same species. Although rare, water can act as a medium for pollination. But worldwide, more than 70% of flowering plants rely on animals to transport pollen for them.

The relationships between flowering plants and their pollinators have been evolving since the early Cretaceous (140 million years ago). These are mutually beneficial relationships in which the animal gains food and nutrients, and the plant is assisted in reproduction. The plants produce nectar, a nutritious sugar-based substance that attracts the pollinator, and the pollen is picked up in the process of collecting the nectar. There are species that cheat of course, and have become adept at "nectar robbing," by taking nectar without passing the anthers of the flower where pollen is located. It's fun to watch a mixed group of bee species on flower garden plants such as Hasta to see which of them enter through the mouth of the flower and which ones make but a brief stop at the base of the flower, where a tiny hole divulges their more direct route to the nectar.

Flowers use color, shape, odor, and timing to appeal to pollinators. "Pollinator Syndromes" describe flower characteristics, or traits, that may appeal to a particular type of pollinator. Plants such as the Maryland state flower, the Black Eyed Susan, provide easy access to nectar and attract a variety of pollinators. Others such as the Trumpet Vine have evolved to minimize the amount of pollen wasted by random visits of pollinators to other flower species. With its bright red flowers and deep tubular blossoms it specializes in attracting hummingbirds which can reach the nectar with their long straight bill. If you encounter Skunk Cabbage in bloom in early spring along local creeks you may be put off by the skunk-like odor, but it is a siren call to beetles and flies.

Who are the Pollinators?

Pollinators come in all shapes and sizes. At least 200,000 invertebrate species act as pollinators including bees, butterflies, moths, flies, beetles, and yes, even mosquitoes. (While the female mosquito is extracting blood to produce eggs, the males are extracting nectar.) There are an estimated 2,000 species of vertebrate pollinators. Hummingbirds and bats of course, but also surprises like doves, opossums, and lizards.

Pollinators provide indispensable ecological and economic benefits. Several species do both. The Mexican long nose bats pollinate both the saguaro cactus, which provides homes and food for a multitude of desert species, and the Agave, which supplies us with tequila for our margaritas. Globally, pollinators are important for the production of roughly 30 percent of the human diet, edible oils, fibers such as cotton and flax, alcoholic beverages, and medicines created from plants. In the US more than 150 food crops like almonds, apples, blueberries, tomatoes, and squash rely on pollinators. A lot of our favorite imports - like chocolate and coffee - too.

Insects are the dominate pollinators world wide, and bees are considered the most important. There are over 4000 species of bees in the US, and with a few exceptions they are wild bees native to the US. But despite this, when people hear "bee" most think of the honeybee. Honeybees were brought here from Europe in the seventeenth century as a crop pollinator and they have become the single most economically important pollinator in the US. Several estimates of the yearly agricultural services provided by pollinators exceed $15 billion. Pollination services provided by wild bees are also important and have been estimated at $3 billion per year.

Pollinators in Danger

In 2006, the National Research Council put out a report, Status of Pollinators in North America, which documents a serious decline in native pollinators. The report identifies the main causes as habitat loss, pesticide use, and diseases. Habitat destruction is caused by changes in land use. When people convert wild lands for domestic uses the food and nesting requirements of many pollinators are disrupted. Pesticides are a major threat to insect pollinators, although precautions such as better regulation, avoidance of overspray, and changes in the type and timing of pesticide use can reduce the threat.

The US Fish and Wildlife Service lists over 50 pollinator species as threatened or endangered. Continued declines in pollinator activity could mean rising costs for pollinator-dependent fruits and vegetables and the disruption of entire ecological systems.

There are some encouraging responses such as the creation of new habitats in some unlikely places: the US Golf Association's Wildlinks Program is creating wildlife habitat along golf courses; the Farm Bill provides incentives for farmers to build permanent vegetative buffers next to agricultural fields; and PEPCO has been preserving open sunny pollinator friendly habitats along its transmission line corridors such as east of New Hampshire Avenue in lower Sligo Creek Park.

Honeybees and Colony Collapse Disorder

Honeybees have been in the news the last several years because of concerns about what is being called Colony Collapse Disorder (CCD). CCD results in adult bees abandoning their hives, while leaving the young, the queen, and the honey behind. Since the syndrome was identified in 2006 beekeepers are reporting losses of over 30 percent of their hives annually. Significant research has been conducted to understand CCD but as of yet no clear cause has been identified. Most researchers believe CDD is caused by a combination of factors including but not limited to pesticides, parasites, and stress from apiary management such as overcrowding and long distance movement of colonies for crop pollination.

More information on CCD

Questions and Answers: Colony Collapse Disorder

USDA 2010 Honey Bee Colony Collapse Disorder Progress Report

PBS Nature "Silence of the Bees"

Honey Bee Disappearance (CCD) and What You Can Do

Vanishing Bees

Bee Keeping Resources

If you are interested in identification of pollinators and their plant hosts, here are a few good sites to start with:

Checklist of Butterflies of Sligo Creek

Butterflies and Moths of North America

Plants of Sligo Creek

Flora of the Washington-Baltimore area

University of Maryland, Department of Plant Biology - James Reveal's page

The Flora Project, native plants of Alexandria, VA

What You Can Do To Protect Pollinators

There a number of steps you can take to protect and encourage pollinators.

What You Can Do To Protect Pollinators Fact Sheet

Creating Pollinator Friendly Gardens

Pollination occurs in habitats that support and provide for both the pollinator and the plants that they pollinate. Any piece of land from a small urban backyard to large tracks of wilderness can contribute to the mosaic of habitats. Whatever the area of land under your care, there are several easy things you can do to help protect pollinators and sustain pollination services.

One of the easiest (and most rewarding) ways to provide suitable habitat for pollinators is to plant a wide variety of locally native flowering plants in your garden. Beyond your own backyard, you'll find many other places where pollinator habitats can be restored or protected. Through community or school gardening programs, you can encourage the planting of native flowers in local spaces such as parks, playgrounds, roadways, golf courses, and around public buildings. Vegetable gardens are another great way to provide food for both you and native pollinators.

Here are a few sites to get you started:

Pollinator Partnership, Pollinator Gardening resources

Fish and Wildlife Service Plant a Pollinator Garden

US Forest Service, Gardening for Pollinators

Pollinators are Garden Essentials

All Vegetables Require Pollination, But Not All Achieve it the Same Way

Botanical Garden, the Butterfly Garden

Gardening Tips from the Smithsonian Butterfly Garden - Video

Pollinator Friendly Planting Guides, NAPPC

Grounds for Nature Ecological Landscape Design and Native Plant Nursery, wildflower catalog with pollinator list

National Wildlife Federation's Backyard Habitat Program

MD Local Native Plant Society

VA Local Native Plant Society

Xerces Society for Invertebrate Conservation Resources "Attracting Native Pollinators"

National Arboretum Gardening Page

National Pollinator Week

Each year the final week of June is celebrated as "National Pollinator Week" with a variety of events across the US. In September 2006 the US Senate signed Resolution 580 designating National Pollinator Week to recognize "the importance of pollinators to ecosystem health and agriculture in the United States". The Secretary of Agriculture followed with a proclamation "calling on the people of the United States to join in celebrating the vital significance of pollinators". www.fws.gov/pollinators/pdfs/pollinatorweekres580.pdf

These are some of the events planned in the DC metropolitan area during June 20-26, 2011


June 24 (Friday) - Montgomery Parks - Pollinator Party 10:00 a.m. - 11:00 a.m.
Learn why plants need bugs and bugs need plants. We'll look at form and function to learn how bumbling beetles, buzzing bees and hovering hummingbirds help our native plants survive and thrive. Ages: 5 Yrs. to 10 Yrs. fee $6.00. Cabin John Regional Park, Bethesda, MD

June 21 (Tuesday) - Beltsville Bee Research Lab - Open House 10:00 a.m. - 3:30 p.m.
The BRL will host an open house for the public to highlight honey bee research activities conducted at the nation's capital by the USDA Agriculture Research Service. Visit the lab and hear about our research, advanced beekeeping techniques, and how to identify bee diseases.

June 21 (Tuesday) - Maryland Pollinator Conservation Planning Short Course
The content of this course is tailored to the needs of NRCS conservation planners, Soil and Water Conservation Districts, Cooperative Extension, state agencies, crop consultants,  farmers, land managers, and master gardeners. Beltsville, MD

District of Columbia

June 24 (Friday) - USDA Pollinator on the National Mall
USDA will be hosting a festival on the lawn of the South Agriculture Building in DC next to the People's Garden from 10am to 2pm. Government and Non-government Organizations will be supplying information on pollinators and pollinator conservation. Participants will include USDA, USFS/Pollinator Live, People's Garden, EPA, FWS, USGS, NPS, Bat Conservation International, America the Beautiful, and a local beekeeping organization. Includes demonstration honey bee hives and other activities.


June 25 and 26 (Saturday and Sunday) - Arlington Demonstration Gardens
Arlington's Bon Air Park is home to two demonstration gardens maintained by the Master Gardeners of Northern Virginia, in support of the Arlington County Office of Virginia Cooperative Extension. Visit the Sunny Demonstration Garden on Saturday, June25, to learn what's happening in the early summer garden, how to attract birds and butterflies, and how to maintain your garden during the hot days of summer. Then, visit the Shade Demonstration Garden on Sunday, June 26, to learn about summer color and texture for shady places in your yard, attractive ground covers for replacing invasive English ivy and planting for pollinators.

June 25, 2011 - Rockwood Honey Bee Festival - noon - 5:00 p.m.
There will BEE something for everyone of every age; music, face painting, arts and crafts, bee items for sale such as beeswax candles and local honey, refreshments, games, nature activities and more. There will be informative programs about backyard beekeeping, gardening for bees, current apiculture news and more. Plus view our live honeybee observation hive. Sponsored by the Rockwood Park Backyard Beekeepers Association. Details: 804-674-1629 or email mrbeeva@yahoo.com. Rockwood Nature Center, 3401Courthouse Road, North Chesterfield, VA,

For more information and a list of other events across the country
visit Pollinator Partnership.

General Pollinator Information and Education Resources

Pollination Quiz

Pollination in Poetry and Prose

Pollinator Conservation Factsheets

Pollinator Partnership education resources

Ecological Society of America Communicating Ecosystem Services Project, Pollination Toolkit

Natural Resources Conservation Service's Backyard Conservation Program

National Wildlife Federation's Backyard Habitat Program

The Inouye Database: An Interactive Bibliography of Pollination Publications, NBII

Places to Go

Smithsonian Butterfly Garden

US Botanical Garden

The People's Garden Apiary

Brookside Garden

Wings of Fancy, Live Butterfly Exhibit at Brookside Gardens, May - September


Pollinator Live, a Distance Learning Adventure

DC Area Butterfly Garden Beginning to Grow

How to Build a Bee Box Video

FREE 2011 calendar from World Food. It features facts on what foods are pollinated by what pollinator along with healthy food ideas.

Pollinator Related Images

North American Butterfly Association

Butterflies and Moths of North America

Monarch Watch (University of Kansas Entomology Program)

Celebrating Wildflowers, Bumblebees by David Inouye

Bat Conservation International Photo Library

Organizations Working on Pollinator Conservation

North American Pollinator Protection Campaign

Pollinator Partnership

The Xerces Society for Invertebrate Conservation

Pollinator Conservation Consortium - Arizona-Sonora Desert Museum

The Hummingbird Society

Bat Conservation International

Fish and Wildlife, Pollinators

Forest Service, Pollinators

Events and Milestones

In 2007 the Post Office released a Pollinator Commemorative Stamp, an intricate ecological masterpiece of bee, butterfly, hummingbird and bat busily at work in full-color flowers.

Takoma Park Crosses Finish Line in Race to Become First MD Community Wildlife Habitat

Pollinator Nature Walk in Sligo - June 30, 2007

Some text is excerpted from, Kranz, R. 2007. Learning About the Birds and Bees. Takoma Voice. July 2007. If you have photos or events to add to this web site please contact Rhonda Kranz rhonda2 AT kranzcons.com