Sticky paper on bumpers reveals scale of bee deaths due to car collisions

A team in Utah has found that bee deaths due to collisions with automobiles in the western parts of the United States may be in the tens of millions every day.

In their paper published in the journal Sustainable Environment, Joseph Wilson, Thomas Porter and Olivia Messinger Carril, described how they calculated likely bee deaths due to collisions by counting the number that were killed by their own vehicles on driving trips around Utah.

Prior research has shown that bee populations around the world are shrinking, which is very bad news for food growers, as bees are a major pollinator. It is currently believed that the decline is due to a variety of factors, all based around human activity; from encroachment, to pesticide use to global warming. In this new effort, the team in Utah suggests collisions with vehicles should be added to the list.

The work by the team involved applying sticky paper to the bumpers of their vehicles and then driving them around Utah on 29 different trips over the years 2018 to 2021. After each trip, the dead bees stuck to their bumpers were removed, identified by genus and counted. In all, the researchers drove 9,334 kilometers and found that every trip resulted in at least one dead bee.

They also found some trips were worse than others. Driving from Salt Lake City, to Moab, for example, resulted in between 50 and 175 bee deaths, depending on the weather conditions. To estimate total bee kills per vehicle, they noted the size of the sticky paper and how many bees were stuck to it, and used those numbers to make an estimate of the total number of bees killed all across the front of a vehicle.

Then, noting that approximately 94,000 trips are made by other drivers over the Salt Lake City to Moab, stretch of highway each day, they calculated that total deaths along just that length of highway would amount to millions of dead bees every single day during warm weather. When including other roads and highways in Utah and other nearby states in America’s west, the estimates reached into the tens of millions—and perhaps into the billions.

The researchers suggest their informal findings indicate that far more bees are being killed by road collisions than has been thought. They also note, that reducing such deaths could be done by not putting flowering plants in the median strip between roadways.

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