A controversial type of pesticide linked to declining global bee populations appears to scramble bees’ sense of direction, making it hard for them to find home. Starved of foragers and the pollen they carry, colonies produce fewer queens, and eventually collapse.

The phenomenon is described in two new studies published in Science. While they don’t conclusively explain global bee declines, which almost certainly involve a combination factors, they establish neonicotinoids as a prime suspect.