Agricultural Literacy Curriculum Matrix
Conserving Bumble Bees
9 - 12
This lesson introduces the importance of bumble bees and other pollinators. Using a case study approach, students will examine bumble bee population surveys and use the scientific method to discuss possible causes for the decline of pollinators. Students will then determine which land management conservation strategies in agricultural ecosystems are most successful in attracting and supporting bumble bee populations.
- How to tell the difference between honey bees and bumble bees article
- 1 tomato or picture of a tomato
- Conserving Bumble Bees student worksheet (continued from Activity 1)
Essential Files (maps, charts, pictures, or documents)
bumble bee: a large hairy bee with a loud hum which aids in the pollination of flowers and lives in small colonies in holes underground
buzz pollination: a technique used by some bees in which the bee hangs upside down on a flower and vibrates her wing muscles causing the release of large amounts of pollen
confounding factor: a variable that is not able to be controlled by the scientist and may impact the dependent variable
control group: a group that does not receive a treatment; minimized the effects of variables other than the independent variable; allows for comparison of treatment effects
dependent variable: a factor that can is measured over the course of an experiment; change will be based on the independent variable
honey bee: a stinging winged insect that collects nectar and pollen, produces wax and honey, and aids in the pollination of flowers
independent variable: a factor that is changed by the scientist
pollination: the transfer of pollen from the anthers of a flower to the stigma of the same flower or of another flower
replication: multiple runs of the same experimental conditions are conducted to determine if an outcome is consistent and predictable; reduces variability in experimental results, increasing their significance and the confidence level with which a researcher can draw conclusions about an experimental factor
Did You Know? (Ag Facts)
- Bumble bees can easily be distinguished from honey bees. Bumble bees have a large, fuzzy body with thick bands of yellow and black.1
- Bumble bees do make honey, but only in small amounts. Their greatest value is to aid in the pollination of flowers.1
- Bumble bees live for one season before they die.1
- Bumble bees leave a scent mark on the flowers they have visited. This saves other bees time by telling them that the flower has already been probed for nectar.2
Background Agricultural Connections
Prior to this lesson students should be familiar with designing experiments and be knowledgeable of vocabulary including dependent and independent variable, control treatment, confounding factor, and replication. A very basic understanding of bumble bee biology would also be helpful (such as understanding of the mutualistic relationship between bees and flowers).
Key STEM Ideas:
An important part of making informed decisions about socioscientific issues requires students to examine and evaluate data to determine if a problem exists, identify potential causes of the problem, and evaluate solutions as they are implemented under real-world conditions. This lesson provides students with the opportunity to become familiar with methods used by real scientists to identify population declines in species of bumble bees and use real-world data to identify and select successful conservation strategies that can be used by growers wanting to balance agricultural production while minimizing environmental impacts.
Connections to Agriculture:
Insects are responsible for the pollination of approximately 80% of all flowering plants including both wild plants and agricultural crops. With adequate pollination, plants produce fruits, nuts, and berries which are consumed by humans and other animals. Proper pollination also produces seed allowing for plant reproduction in the wild and continued agricultural crop propagation.
According to a Cornell University study, honey bees and other insect pollinators in the U.S. contribute an estimated $29 billion dollars annually in farm income (Calderone, 2012). U.S. agriculture gains approximately $15 billion of this total value from honey bee pollination alone, but often overlooked are the specialized pollination services provided by bumble bees.
Bumble bees exhibit a unique behavior known as buzz pollination, in which the bee hangs upside down on a flower and vibrates her wing muscles causing the release of large amounts of pollen. Buzz pollination is especially valued by growers of tomatoes, peppers, and cranberries because it leads to better fruit set than pollination by honey bees. In addition, bumble bees are some of the only species which function effectively in greenhouse settings where crops such as tomatoes, sweet peppers, and strawberries are grown. As a result, growers of these crops often purchase colonies of bumble bees to pollinate their crop. The safety and conservation of bumble bees is crucial in the success of these farming operations.
In order to show a need for federal or state protections that impact agricultural policy, researchers must show evidence of population declines. However, it can be difficult to determine if declines are occurring if baseline data is absent or inaccessible.
If declines can be determined, researchers can then begin to examine potential causes of the decline and evaluate solutions to the problem. In the case of bumble bee decline in the U.S., researchers suspect that habitat and foraging resource loss is a limiting factor in agro-ecosystems’ ability to support bumble bee populations.
Another step toward conservation of bumble bees requires researchers to compare land management strategies and their effect on bumble bee species’ abundance and diversity.
Interest Approach - Engagement
- Show students a tomato or picture of a tomato. Have students discuss and list what is needed to produce tomatoes.
- Facilitate discussion about the need for proper growing conditions (soil, nutrients, light, temperature, moisture) and adequate pollination. Be sure students understand that pollination allows the plant to produce the fruit and seeds.
- Ask students how pollination takes place in the flower of a tomato plant. If they answer "bees," ask them what kind of bees? Are there different kinds of bees and pollinating insects? (Yes)
- Ask students what the difference is between a honey bee and a bumble bee. Compare and contrast the two bees. Inform students that they will be learning about the bumble bee today.
Part 1: Value of Pollinators and Introducing the Problem
- Distribute one copy of the Conserving Bumble Bees worksheet to each student.
- Read "Part 1: Value of Pollinators" with students to provide context for the issue of conserving bumble bees.
- Following the reading, discuss the agricultural and natural ecosystem implications if bumble bees were no longer providing pollination services. Consider discussing questions such as:
- Could other pollinators take the place of bumble bees? (No, bumble bees are some of the few species that can buzz pollinate.)
- What would happen to wild plants that rely on bumble bees for pollination? (If no other pollinator could adequately pollinate these plants, no seeds would be produced and the plant population would decline or possibly become extinct.)
- What effect might the loss of bumble bees have on consumers? (Crops pollinated by bumble bees would likely be more expensive, or might be unavailable.)
- Continue reading "Part 1" of the worksheet, The Problem: Pollinators in Peril with students.
- Using what they learned from the reading, have students explain how scientists can tell if a species is in decline or not. Students should understand that:
- Historical baseline data is necessary to determine if populations are declining.
- In some cases, historical data or counts are simply not available making it impossible to provide evidence of population declines.
- Consistent and repeatable survey methods are very important when comparing historical abundance counts to current abundance counts.
- Discuss the concept of measuring relative abundance which was explained in the reading. Relative abundance is one way of determining if the proportion of each species has remained stable over time or has changed. You may wish to provide students with a relatable example by comparing relative abundance of girls to boys in the class (# of girls/total vs. #of boys/total).
- Have students examine Figure 4 on page 2 of the worksheet.
- Answer the questions as a whole class or in small groups. Discuss answers and clarify as needed.
- Once students are confident in reading a graph of relative abundance, assign them to decipher the graphs in Figure 5 and answer the three follow-up questions on pages three and four.
Part 2: Likely Culprits of Bumble Bee Decline?
- Now that students have seen evidence of population decline in some bumble bee species, they can begin to formulate ideas or hypotheses of why this decline might be happening. Provide a very brief discussion of what bumble bees need to survive. Refer students to page 4 of the worksheet which contains the following list:
- High-quality habitat for nesting
- Plentiful food and water resources nearby throughout the spring, summer, and fall
- An environment relatively free of pests, parasites, pathogens, and pesticides
- Continue your class discussion by asking students to brainstorm and formulate hypotheses about factors that might impact bumble bee populations. As you discuss various hypotheses, point out to students that some factors or causes of the bumble bee decline may be driven by human actions.
- Instruct students to complete "Part 2" of the worksheet. They will read an excerpt from a blog post by Matt Miller from the Nature Conservancy and answer four questions.
- After completing "Part 2," facilitate a discussion comparing the factors they came up with and some of the factors discussed in the blog post. Possible discussion topics could include:
- Were any factors missing?
- Did any factors surprise you?
- What actions should be taken to help conserve pollinators?
Part 3: Taking a Closer Look at Habitat Loss
- Assign students to read "Part 3" of the Conserving Bumble Bees handout in small groups and have students discuss how land has changed over time.
- Discuss the role of humans in land use and the importance of balancing food, fuel, and fiber production with the sustainable use of natural resources (such as converting land from native prairie to agricultural production).
- Note: As a supplement to this discussion, you may have students read the article, "The Enormous Threat to America's Last Grasslands" from The Washington Post which was published on June 16, 2016 about the threat to grasslands in the U.S.
- This section provides a great opportunity to facilitate a discussion about how to decide what land is used for agricultural production and what land should be left undisturbed to protect biodiversity. Consider the following questions:
- Should money be spent to protect animals such as bumble bees and the native plants they pollinate?
- Who should make this decision?
- What factors should be considered when making this decision?
- Assign students to work individually or in small groups to design an experiment to test the effect of land management strategies on bumble bee abundance.
- Discuss each group's experimental designs as a whole class. Be sure students mention the following:
- The independent and dependent variables
- The control treatment
- How the experiment can/will be replicated
- Confounding factors that should be considered
- Read the section in the worksheet titled Examining the Effectiveness of Conservation Strategies found in "Part 3."
- Have students examine Figure 8 which is a graph of bee forage flower abundance in relation to number of bumble bees.
- Assign students to answer the follow-up questions on page 9. Expand the topic with a class discussion about the trends they observed across land management types for:
- Bee forage flower abundance
- Number of bumble bees
- Also discuss:
- What correlation or relationship do they see between these two variables?
- Which land management strategy would they recommend to growers?
- Have students reflect on what they have learned about bumble bee decline and conservation strategies. How can they use the data presented to inform agricultural policy?
Concept Elaboration and Evaluation
After conducting these activities, summarize and review the following key concepts:
- Bumble bees and other pollinators are important to the production of most food crops.
- There is evidence of a reduction in bee colonies across the United States. There are many potential contributing factors.
- How land is used is an important topic in agriculture and our society.
- Various land management techniques exist to preserve the quality and biodiversity of land while still allowing it to be farmed in order to produce food, fiber, and fuel for our population.
Data and graphs found in the student worksheet and the Background Agricultural Connections section were taken from the following works:
- Calderone, N. W. (2012). Insect Pollinated Crops, Insect Pollinators and US Agriculture: Trend Analysis of Aggregate Data for the Period 1992–2009. PLoS ONE, 7(5), e37235. http://doi.org/10.1371/journal.pone.0037235
- Cameron, S. A., Lozier, J. D., Strange, J. P., Koch, J. B., Cordes, N., Solter, L. F., & Griswold, T. L. (2011). Patterns of widespread decline in North American bumble bees. Proceedings of the National Academy of Sciences, 108(2), 662–667.
- Carvell, C., Meek, W. R., Pywell, R. F., Goulson, D., & Nowakowski, M. (2007). Comparing the efficacy of agri-environment schemes to enhance bumble bee abundance and diversity on arable field margins. Journal of Applied Ecology, 44(1), 29–40.
- Colla, S. R., Otterstatter, M. C., Gegear, R. J., & Thomson, J. D. (2006). Plight of the bumble bee: pathogen spillover from commercial to wild populations. Biological Conservation, 129(4), 461–467.
- Gallant, A. L., Sadinski, W., Roth, M. F., & Rewa, C. A. (2011). Changes in historical Iowa land cover as context for assessing the environmental benefits of current and future conservation efforts on agricultural lands. Journal of Soil and Water Conservation, 66(3), 67A–77A. http://doi.org/10.2489/jswc.66.3.67A
- Goulson, D., Lye, G. C., & Darvill, B. (2008). Decline and conservation of bumble bees. Annu. Rev. Entomol., 53, 191–208.
- Erin Ingram: University of Nebraska-Lincoln, IANR Science Literacy Initiative, National Center for Agricultural Literacy
- Molly Brandt: University of Nebraska-Lincoln, IANR Science Literacy Initiative, National Center for Agricultural Literacy
Suggested Companion Resources
Erin Ingram and Molly Brandt
University of Nebraska-Lincoln
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