bees

To keep bees from disappearing, listen to their buzz

An inexpensive acoustic listening system can monitor bees in flight using data from small microphones in the field. New research shows how farmers could use the technology to monitor pollination and increase food production.

According to recent studies, declines in wild and managed bee populations threaten the pollination of flowers in more than 85 percent of flowering plants and 75 percent of agricultural crops worldwide. Widespread and effective monitoring of bee populations could lead to better management; however, tracking bees is tricky and costly.

long-tongued bumble bee queen
Bombus balteatus queen collecting nectar from the alpine clover, Trifolium parryi. The buzzes of bees flying from flower to flower tell scientists how much pollination the clover population is getting over time and predict seed production in these alpine wildflowers. (Credit: Jennifer Geib/Appalachian State University)

“Causes of pollinator decline are complex and include diminishing flower resources, habitat loss, climate change, increased disease incidence, and exposure to pesticides, so pinpointing the driving forces remains a challenge,” says Candace Galen, professor of biological science in the University of Missouri College of Arts and Science.

“For more than 100 years, scientists have used sonic vibrations to monitor birds, bats, frogs, and insects. We wanted to test the potential for remote monitoring programs that use acoustics to track bee flight activities.”

First, the team analyzed the characteristic frequencies—what musicians call the pitch—of bee buzzes in the lab. Then, they placed small microphones attached to data storage devices in the field and collected the acoustic survey data from three locations on Pennsylvania Mountain in Colorado to estimate bumble bee activity.

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Using the data, they developed algorithms that identified and quantified the number of bee buzzes in each location and compared that data to visual surveys the team made in the field. In almost every instance, the acoustic surveys were more sensitive, picking up more buzzing bees.

“Eavesdropping on the acoustic signatures of bee flights tells the story of bee activity and pollination services,” Galen says.

“Farmers may be able to use the exact methods to monitor pollination of their orchards and vegetable crops and head off pollination deficits. Finally, global ‘citizen scientists’ could get involved, monitoring bees in their backyards.”

long-tongued bumble bees
Long-tongued bumble bee queens of Bombus balteatus visit flowers of the alpine skypilot Polemonium viscosum. These large bees have a distinctive flight buzz, the bee version of a cargo-plane flying from flower to flower. (Credit: Zoe Moffett/Colorado College)

Currently, using the algorithms developed in this study, the team is developing a smartphone app that could record buzz activity as well as document the bees photographically. Future studies could determine whether bees detect competitors by sound and whether flowers have chemical responses to bee buzzes, Galen says.

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The study appears in PLOS ONE. The National Science Foundation funded the research. The content is solely the responsibility of the authors and does not necessarily represent the official views of the funding agency. Coauthors of the study are from Webster University, Lincoln University, and the University of Missouri.

Source: University of Missouri

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