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Extension > Local Extension Offices > Mahnomen > Garden > Articles > Plants for Pollinators: Part Two

Plants for Pollinators: Part Two

Part One answered the question “What is Pollination” Now let’s take a look at pollinators...

Efficient pollinators
Bees have evolved alongside flowers, making them the most efficient pollinators. Bees have developed efficient ways to carry pollen, and flowers have developed sweet nectar to serve as a reward. Some species of bees have branched (like a tree branch) hairs that pollen grains can attach to, other species have dense hair on the thorax, or pollen baskets on the hind legs to carry pollen back to the nest. 
There are other behavioral characteristics that bees have that contribute to their efficiency.  Female bees have strong flight and navigational skills that enable them to leave the nest, locate and capture pollen and return back to the nest. They orientate themselves early in the season with flights that circle the nest, memorizing navigational landmarks enabling them to always return to the nest. 
Bees also have an important behavioral characteristic labeled constancy. This is the tendency to stick with one species of flower during a  foraging trip.  This is important for pollination because pollen will not germinate on the stigmatic surface of another flower, pollen from a squash plant will do nothing for a starflower.  By visiting different flowers of the same species, cross-pollination happens resulting in more genetic variance in the population and a greater ability to adapt to changing environmental conditions. 

Are all bees the same?
If asked to name a species of bee, people commonly name the honeybee.  When asked to draw a bee, most of us would probably draw something resembling a bumblebee. 

A lot of information is available about honeybees, there are resources available online for anyone interested in beekeeping and honey collection.  (UofM resource link)  Apis mellifera is used extensively in commercial pollination for crops and other plants, a service which is valued in the billions of dollars. The honeybee however, is not the most efficient pollinator.

Bumble bees are the more efficient, and effective pollinators. Likely due to their large size, and hairy bodies.  When a larger bumblebee lands on a flower, they not only knock off a bit of pollen, but often touch both male and female parts of a flower which leads to more effective pollination. 

Minnesota is home to 420 species of native bees, including 19 species of bumblebees.  For detailed information on these bumble bees visit the University of Minnesota Extension’s Bee Atlas website. (https://www.extension.umn.edu/environment/citizen-science/bee-atlas/)

Other pollinators include flies, wasps, beetles, butterflies and moths.  These insects visit flowers and feed, or find mates.  This activity contributes to pollination but not as efficient and effectively as bumblebees. 


The Global Importance of Pollinators
Research has verified that the majority of flowering plants in the world are pollinated by insects
and animals (Source: Ollerton et al. 2011. How many flowering plants are pollinated by animals? Oikos 120: 321–326). Of this, the estimated the value of pollination service worldwide at $162 billion annually (Source: Gallai et al., 2009.)  Of the total amount of food produced in the world, pollinators are responsible for 35%; that works out to about 1 in every 3 bites of food is pollinator dependent!

Let’s put this into something a little more tangible, imagine a breakfast plate filled with buttery toast dolloped with jam, scrambled eggs sprinkled with cheese, yogurt livened up with fresh or dried fruits and nuts, juice, and coffee or tea dressed up with creamer. If we take the foods that are pollinator dependent off the plate, we’re left with little more than plain eggs, dry toast, black coffee (no tea!) and a glass of water.  No fruit or nuts are produced because they require pollination.  Less dairy products, because dairy cows graze on clover and alfalfa which is a pollinator dependent crop. The production of dairy products would be reduced by as much as half, leading to a rise in prices which would make items like milk, cheese, and yogurt essentially luxury grocery items. Even non-dairy milks, cheeses and yogurts would be unavailable to us.

While honey bees are very important, native bees (bumble bees and the many species of solitary bees that live around us) are valued at $3.44 billion and pollinate crops like alfalfa, squash, blueberries, cranberries and tomatoes, that honey bees are not very effective at pollinating.  

 

Part three will discuss what is threatening bees and look at what we can do to help. 

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