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Pollinators
Written by Rhonda Krantz
June 2007
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Introduction
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.
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.
On June 29 head to the post office for the beautiful new 41 cent pollinator Commemorative Stamp!
Learn More
Pollinator Nature Walk in Sligo - June 30
National Pollinator Week
June 24 - 30 is National Pollinator Week!
Last year 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". Activities are being planned across the country, including a pollination outing in Sligo Creek on Saturday June 30th.
2007 Pollinator Commemorative Stamp
On June 29 the U.S. Post Office is releasing "Pollination," its most gorgeous stamps ever. Scientist and artist Steve Buchanan has painted an intricate ecological masterpiece of bee, butterfly, hummingbird and bat busily at work in full-color flowers. The commemorative stamp set has been developed to encourage pollinator research, education and awareness.
Check out www.fws.gov/home/feature/2006/USPS_pollinator_stamp.pdf for a view of this beautiful stamp series and run to the post office on June 29th!
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 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. 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 to other 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 400 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. One estimate of the yearly agricultural services provided by pollinators is $14.6. Pollination services provided by wild bees are also important and have been estimated at $3 billion annually. Honeybees have been in the news lately because of concerns about what is being called Colony Collapse Disorder (which results in bees abandoning their hives). There has been some research and lots of speculation but as yet there is no definitive answer as to why this is happening. The potential repercussions of the decline in honeybee populations illustra!
te the danger of balancing our agricultural system on one species of pollinator.
Pollinators in Danger
Last year, 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.
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.
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. But keep watch on this site for pictures and examples of pollinators in Sligo Creek. Or send us photos or information on pollinators that you have.
Links to Pollinator Resources
North American Pollinator Protection Campaign
Ecological Society of America Communicating Ecosystem Services Project, Pollination Toolkit
Pollinator Conservation Consortium - Arizona-Sonora Desert Museum
The Xerces Society for Invertebrate Conservation
MD Local Native Plant Society
VA Local Native Plant Society
DC Local Native Plant Society
Natural Resources Conservation Service's Backyard Conservation Program
National Wildlife Federation's Backyard Habitat Program