malaise trap in German field
A 27-year study in western Germany, using malaise traps placed in protected habitats such as shown above, measured total biomass of flying insects and found a decline of more than 75 percent in that time period. Researchers suggest large-scale trends could be driving the decline and note the need for similar study to measure insect levels worldwide. (Photo originally published in Halmann et al., PLOS ONE, October 2017)