Meghan Bialt-DeCelie ’19

Bees play a critical role in crop survival. Because of this, farmers and scientists must always stay ahead by following patterns in their behavior to quickly manage and appropriately respond to complications in their population growth.

Acoustic analysis of organisms is not a new concept; however, it is not often used on insects. Researchers led by Nicole Miller-Struttmann PhD from Webster University explored the practicality of acoustic surveys of foraging bees. They studied the buzzing frequencies of mainly two bee species: Bombus balteatus and Bombus sylvicola. 15 B. balteatus and 13 B. sylvicola bees were collected and were allowed to forage from a variety of plants in a flight cage. Their buzzes, caused by their thorax oscillating while flying, were recorded. To make the sound based survey more efficient, an algorithm utilizing Computational Auditory Scene Analysis was developed to help filter out irrelevant frequencies and isolate buzzes.

The effectiveness of the acoustic survey was determined by comparing it to the traditional visual survey for bee density. Visual surveys involved counting each individual bee within a 50 cm radius of the observer. The correlation between sound and visual surveys was high with r = 0.973 and significance of P = 0.0011. This suggests that the acoustic survey can reliably be used to analyze bee activity. Certain traits of a bee such as size and tongue length can improve the efficiency of pollination. Researchers were able to relate these traits to identifying buzz frequencies. The correlation of higher frequencies observed in bees with shorter tongues and wings had a P < 0.0001.

With so many factors that affect bee pollination, including climate change and diminished habitats, a more efficient and noninvasive survey can help farmers recognize bee population fluctuations faster.

References:

1. N. E. Miller-Struttmann, et al., Flight of the bumble bee: Buzzes predict pollination services. PLOS ONE (2017). doi: 10.1371/journal.pone.0179273
2. Image retrieved from: https://commons.wikimedia.org/wiki/File:Honey_bee_(Apis_mellifera).jpg