Declining Population in Bumble Bee Species

Rusty patched bumble bees were listed as endangered in 2017. This is just one species of bumble bee that has been on the decline. This is a graph showing the number of rusty patched bumble bees found in Iowa and Illinois from 2017 (the year it was listed as endangered) to 2023. While the dataset is small, a slow incline in the number of rusty patched bumble bees can be seen since 2017.

Numbers are from “Rusty Patched Bumble Bee (Bombus affinis) Status Review: Summary and Evaluation” (U.S. Fish and Wildlife Service Minnesota-Wisconsin Ecological Services Field Office Bloomington, MN 55425 August 2022). The 2022 and 2023 data is from the Moline branch of the U.S. Fish and Wildlife field office.

• What is the human impact on bumble bee populations?

• Looking at the table, what patterns in the data do you notice?
• What are some things that might have caused the fluctuation in numbers?
• If bumble bees were to vanish how would that affect our ecosystems?
• What human actions could have caused the numbers to go up or down?
• What natural events may have caused the numbers to go up or down?
• Have conservation efforts helped the declining population of bumble bees?

Students could:

• Research how pollinator pockets may help bumble bees.
• Research the weather patterns from the years represented in the table.
• Find out what bumble bees eat, what eats them and what their job is an ecosystem. (This helps students understand what might happen if they went extinct.)
• Survey an area that is host to bumble bees that are foraging.
• Research what produce or crops in our area are pollinated by bumble bees

• Bumble Bee Watch | Bumble Bee Field Guide: Guide that will help students determine if a bee if a survey has been done.
• U.S. Fish and Wildlife Service | Rusty Patched Bumble Bee: This background information on the rusty patched bumble bee lists general characteristics and outlines the history of it being put on the endangered species list.
• U.S. Fish and Wildlife Service | How to Build a Pollinator Garden: Instructs students how they can help bumble bees and other pollinators by planting pollinator gardens.
• U.S. Fish and Wildlife Service | Community's Collaboration Key for Critical Pollinator: This article explains the job bees have in providing food on our tables. It also lists things that are causing the bumble bee population to dwindle. It goes on to explain how citizen scientists can gather data to share with the proper organizations.
• Bumble Bee Conservation: While this organization is UK based, it has information as to why bees need our help and what we can do about it.
• Iowa Bumble Bee Atlas: Iowa Bumble Bee Atlas is a statewide community science project aimed at tracking and conserving Iowa's native bumble bees.
• Environmental America | The American bumble bee is on the decline: This article shows how declining bee numbers can affect other parts of the ecosystem.
• Horizon Magazine | Grassland Studies, Radar-Tracked Bumblebees Offer Clues For Protecting Pollinators: This article shows how grasslands (which are wind pollinated) could take over if there are not enough pollinators for wildflowers (many of which are legumes). Grasses take nitrogen from the soil, while legumes are nitrogen fixing, helping the heath of the soil.