Are vehicle strikes causing millions of bee deaths per day on western United States roads? Preliminary data suggests the number is high

Pollinator populations face multiple threats, including habitat modification, complete habitat loss and habitat fragmentation. Efforts to increase habitat for potentially imperilled species include the recognition of roadside vegetation as providing important floral and nesting resources for bee species. Though roadsides be good bee habitat because they either 1) open up the dense forest canopy in mesic landscapes or 2) include more flowering plants because of increased runoff in arid landscapes, there may also be detriments. Most importantly, bees that forage or nest near roads may be more likely to be hit by moving vehicles. To date, there is no comprehensive study that quantifies bee morality from moving vehicles. Here, we used sticky traps attached to car bumpers to determine bee mortality on trips throughout Utah, USA. These data were then used to extrapolate likely average and minimum levels of bee mortality across all vehicles that drive in a day along given roads, based on Department of Transportation statistics. Though numbers are only estimates based on projection, they hint at incredibly high day-to-day mortality rates of pollinators that occur near roadways. Specifically, we forecast that tens of millions of bees are killed daily on roads in western states. Transportation authorities may want to consider ways to maximize the value of roadside habitat, while minimizing bee–vehicle collisions.