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It's National Pollinator Week from June 18-24, 2018. Let's celebrate with some science-themed activities.

What is Pollination?

Pollination is an essential process for plants to create healthy fruit and seeds. Scientifically, pollination is the movement of pollen (the colorful powdery dust) from anther of a flower to the stigma of the same or another flower.

(“Mature flower diagram” by Mariana Ruiz LadyofHats. Public Domain image at Wikimedia Commons.)

From the diagram it seems simple and straightforward, but pollination takes many different forms depending on the plant. Some types, for example grasses, produce light pollen grains that may be carried by the wind or water from plant to plant. Other plants, for example squash and cucumbers, require insects, birds, or bats to carry the pollen.

Without this pollination assistance, fruit and/or seeds would not be formed. In fact, about a third of the food we eat is the direct result of pollination by insects.

Why Bees?

Bees are important pollinators. More than 100 agricultural crops in the United States are pollinated by bees. Examples of bee-pollinated crops include watermelons, cantaloupe, citrus, and apples. (See a more complete list of plants pollinated by insects).

While a worker bee is in a flower gathering nectar, pollen from the anther often sticks to her hairy body. Because the bee generally visits a number of the same type of flower in a patch, she will rub some of the pollen off onto the stigma of another flower and complete pollination. Some flowers such as orchids have elaborate mechanisms to make sure bees are dusted with pollen when they visit.

Part of the reason honey bees are so important as pollinators is that they actively seek out flowers with pollen, unlike pollinators such as bats and hummingbirds that are primarily interested in nectar. Pollen stored in the hive is used as a source of protein in feeding the developing larvae.

Activity:  Keep a Pollinator Diary

Have you seen any pollinators today?

The first step towards understanding pollinators is being able to recognize them. Obtain or make a small notebook for each child. For the next seven days, have them write down or draw pictures of any pollinators they see each day. If they have trouble finding pollinators nearby, consider visiting a zoo, park, or community garden where pollinators might be active.

Note any details, like:

  • What kind of flower is it visiting?
  • Does the pollinator have pollen on its body?
  • If so, what color is the pollen?
  • What time of day it is
  • What the weather is like

This honey bee is visiting a rosemary flower and it is covered with white pollen.

This hummingbird is visiting aloe flowers.

They may use the information they gather to:

  1. Learn to identify common pollinators
  2. Further understand behaviors and habitats of pollinators
  3. Research what plants are visited by pollinators in your area
  4. Design and plant a pollinator garden (see links below for more information)

Extensions:  Take photographs and record the information in an online diary format.

To get excited about pollinators, check out this video:

The Beauty of Pollination - Wings of Life


Related Activity Suggestions:

Looking for more information? Try our growing list of children's books about pollinationat Science Books for Kids.

The penstemons are flowering.

They are a favorite.

Hummingbirds love them.

So do solitary bees. In fact, the stalks are abuzz with bees.

The digger bees and sweat bees land, and crawl right into the flower in no time.

This is the usual view of a bee visiting a flower. The nectaries are at the base, so the bees push their heads deep inside and suck up the nectar with their long tongues.

Then the bee is off to the next flower.

If you are interested in helping bees and hummingbirds, penstemons are great plants to grow.

Just as I was sitting down to write my weekly blog post, my cousin sent me an email. She had received a bug-related item as a gift, and wanted to know more about it. Let's take a look:

(Photograph by Karen Gibson, used with permission)

Any idea what this is?

I'll give you a hint.

(Public domain image of Osmia lignaria from USGS Bee Inventory and Monitoring Lab Flickr Photostream)

This small bee is an blue orchard mason bee. It gets the name "blue" for its metallic blue-black color. The "orchard" part is because it is a significant pollinator of crops grown in orchards, such as cherries, apples, plums, and almonds. This bee and its relatives are called "mason bees" because they use mud in their nests, plastering it on like a human mason sticks together bricks with mortar.

Do you see all the pollen in the hairs on the underside of the bee's abdomen? Having large pollen collection areas, combined with the fact the mason bees visit more flowers per minute than other types of bees, is what makes them such good pollinators. In fact, just a few orchard mason bees can pollinate the same number of fruit trees as thousands of honey bees.

Back to my cousin's gift. Unlike carpenter bees, mason bees do not excavate nest holes in wood. Instead, they must find beetle galleries in tree trunks to serve as homes for their larvae. Nest holes may be in short supply in places where old tree trunks are removed right away. To help mason bees survive, you can provide a bee house like the one my cousin received. It is the insect equivalent of a bird house.

Building and Hanging an Mason Bee House

If you want to build a mason bee house, drill a series of holes 5/16 to 3/8   inches in diameter (smaller diameter holes may be used by leafcutter bees) six inches deep in pine or fir wood. Space the holes about 3/4 inch apart, the number and design are up to you. Paint and decorate as you wish. Mount the house firmly to fixed surface such as a wall or tree (the bees don't like their nest to swing). Place it where the house will receive early morning sun. These bees are usually active in the spring.

Do not rest the house on the ground, where ants and other crawling insects can get inside.

When a female mason bee finds the bee house, she will gather pollen and nectar into a ball called "bee bread" and put it deep within one of the tunnels. She will lay a single egg on the clump and close up a short chamber by plugging it with mud. Inside the chamber the egg will hatch into a larva, which will feed on the food its mother provided. In a short time it will complete development and turn into a pupa, and then finally an adult bee.

The female bee creates several similar chambers in a row within a single tunnel. You can see the inside of a nest about half way down this USDA page. When she is finished, she will cap the end with a plug of mud, a signal the nest is occupied.

(Public domain photograph of Osmia ribifloris by Jack Dykinga of the USDA.)

Depending on where you live, you might not attract the blue orchard mason bee, Osmia lignaria, to your bee house. There are roughly 500 species of Osmia around the world, however, so you may provide a nest for a related species that pollinates your local plants. For example, the Osmia ribifloris in this photograph is an important pollinator of blueberries.

If she doesn't mind, maybe Karen can send us an update later in the year letting us know if any bees found the house.

Please leave a comment if you have any questions about mason bees or bee houses.