Biologists have long known that Monarch butterflies have been in sharp decline since the late 1990s. A likely culprit is the increased spraying on farms fields of a weed killer, called RoundUp, which kills the milkweed plants that monarch caterpillars depend on as their sole food source.
At the same time, scientists have documented a decline in bees and other pollinators. The causes of the bee collapse are likely complex. But again, one factor frequently discussed is modern industrial-style agriculture, which relies on large volumes of pesticides.
These conclusions, however, raiseda logical question: Of course we take note of what’s happening with large, colorful butterflies and bees. Everyone, even children, notices them – and lots of scientists monitor their populations as their full time jobs.
But what about all the millions of species that are so obscure that nobody studies them or even thinks about them? An answer to that question was recently published in a scientific journal called the Public Library of Science (PLOS Online). Ecologist Caspar Hallman and colleagues documented a 75 percent decline in all flying insects over three decades across Germany. They counted bugs trapped in wildlife preserves surrounded by farm fields – and concluded that the pesticides sprayed on the farms is a possible cause.