Entomologists have been assessing diversity and abundance across western Germany and have found that between 1989 and 2013 the biomass of invertebrates caught had fallen by nearly 80 percent
. From an article on Science magazine: Scientists have tracked alarming declines in domesticated honey bees, monarch butterflies, and lightning bugs. But few have paid attention to the moths, hover flies, beetles, and countless other insects that buzz and flitter through the warm months. "We have a pretty good track record of ignoring most noncharismatic species," which most insects are, says Joe Nocera, an ecologist at the University of New Brunswick in Canada. [...] A new set of long-term data is coming to light, this time from a dedicated group of mostly amateur entomologists who have tracked insect abundance at more than 100 nature reserves in western Europe since the 1980s. Over that time the group, the Krefeld Entomological Society, has seen the yearly insect catches fluctuate, as expected. But in 2013 they spotted something alarming. When they returned to one of their earliest trapping sites from 1989, the total mass of their catch had fallen by nearly 80%. Perhaps it was a particularly bad year, they thought, so they set up the traps again in 2014. The numbers were just as low. Through more direct comparisons, the group -- which had preserved thousands of samples over 3 decades -- found dramatic declines across more than a dozen other sites. Such losses reverberate up the food chain. "If you're an insect-eating bird living in that area, four-fifths of your food is gone in the last quarter-century, which is staggering," says Dave Goulson, an ecologist at the University of Sussex in the United Kingdom, who is working with the Krefeld group to analyze and publish some of the data. "One almost hopes that it's not representative -- that it's some strange artifact."