Impacts on Plants & Pollen

As we learned in Module 7: Plants & Pollen, pollination is a crucial process for humans. Our current agricultural system in the U.S. is hugely dependent on our ability to manipulate insect pollination.

While many people associate honeybees with crop pollination, the human relationship with pollinators is complex. By one estimate, domesticated honeybees pollinate $14 billion worth of seeds and crops in this country every year, or 80% of insect-pollinated crops. However, cereal crops, including wheat, corn, rice, and oats, are in the grass family and are wind-pollinated. But most fruits and vegetables require active pollination by animals, usually insects. Honeybee-pollinated crop species includes fruits such as melons, stone fruits, berries and grapes; vegetables such as cabbage, okra, and cucumbers; and nuts such as almonds, macadamias and walnuts. For a more complete list of plants pollinated by bees, and additional information on the estimated economic value of bees in U.S. crop production, visit The American Beekeeping Federation: Pollination Facts.

Over the last several years, colony collapse disorder (CCD) put the importance of honey bees in the headlines. Everything from new pesticides to cell phone towers (which module author Dr. M. Laurie Henneman from the University of Montana – Western debunked in an essay that you can read here) has been blamed for the sudden mass deaths of worker bees in domestic hives. But attempts to discover a single reason for the collapse, despite a lot of money and time thrown at the problem, have been frustrated. This has led some scientists to believe that a single cause will never be discovered. For more, refer to the BBC article “‘No proof’ of bee killer theory” from 2009. A study from 2009 in which consistent responses to viruses or pesticides was searched for, but not found, supports the view that CCD, if a true phenomenon, could simply be the result of the accumulation of inbreeding and stressors on honeybees over decades. For more on this, visit “Do honeybees have AIDS? from the bioblog” at

Ironically, the CCD problem brings to the fore an issue that has been mostly ignored by everyone except for a handful of scientists who have been trying for years to convince the agricultural community of the danger of depending too much on a single introduced species (honeybees originate from the Old World). For example, a 2002 article by Kremen et al, published long before the advent of CCD, noted that even then honeybees were under stress from disease, pesticides, etc, and that we have been essentially ignoring native bees as a pollination resource. Unfortunately, our system of large monoculture farms sprayed with pesticides is not conducive to encouraging these native pollinators, which require higher-diversity natural habitat nearby. While a lot of research is now being done on CCD and how to prevent or control it, there is still relatively little being done on how we can better utilize native, wild pollinators. For more, visit the Native Pollinators in Agriculture website.

But in most of the world, native pollinators by default do the burden of pollinating. As reported by the BBC (view the complete article here): “The UN Food and Agriculture Organization (FAO) estimates that of the slightly more than 100 crop species that provide 90% of food supplies for 146 countries, 71 are bee-pollinated, primarily by wild bees, and a number of others are pollinated by other insects.”

India is currently facing a pollinator decline somewhat different from that of the U.S. Even though they rely heavily on wild bees and other insects for pollination, there is not an attendant concern for the importance of natural biodiversity, and this seems to be taking its toll. Insect-pollinated crops are not keeping up with wind-pollinated crops in levels of production, and it is suspected that it is the insects themselves that can’t keep up. The scope of the problem clearly is unknown at this point, due to a lack of research on India’s native pollinators, but it is easy to imagine that in many countries, a lack of concern for natural habitat and biodiversity could inadvertently lead to more food crises as native pollinators become more scarce.

Our complex relationship with pollinators serves as a good example for why the still-prevalent attitude that nature is for humans to exploit as we see fit in the short term is arrogant and short-sighted, and could have enormous detrimental impacts on us in the long term. The strongest argument for preserving biodiversity for its own sake is that much of the time, we are sill ignorant of the value to humans that it provides now, and will provide in the future.

Check Your Thinking: Which of the following crops do not rely upon insects for pollination?

a. wheat
b. grapes
c. almonds
d. a and c



Check Your Thinking: What pollinators do most countries in the world rely upon for their crop production?

a. wind
b. domestic honeybees
c. wild bees
d. butterflies


Can you think of other examples of human impacts on plants and pollinators? How can such impacts on plants and pollinators affect humans? To discuss these questions, visit the Forum: Impacts on Plants & Pollen.


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The MSP project is funded by an ESEA, Title II Part B Mathematics and Science Partnership Grant through the Montana Office of Public Instruction. MSP was developed by the Clark Fork Watershed Education Program and faculty from Montana Tech of The University of Montana and Montana State University, with support from other Montana University System Faculty.