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Where Have All the Insects Gone? (sciencemag.org)
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."
I attributed it to climate change and loss of continuous habitat.
It's actually a week-old story, but I only spotted it today. (It wasn't pitched by any reader.) Apologies for running what seems like an old story, but we found it important enough to run it. Thanks.
It's nearly summer here, we got 23C today, and most of the leaves have sprung everywhere. But indeed - where are the insects? Yes, there are the odd bumblebee here and there, but this place (right in the middle of mother nature) is usually buzzing with insects this time of the year, but there is hardly any.
Of course - I can't say that I miss the Mosquito, in fact - it's my sworn enemy, but the rest of the insect hordes seems to be gone as well, I hardly see any banana flies, moths or any common insects here out in the wilderness any more. Maybe there is something going on here?
What this world is coming to - is for you and me to decide.
This has some scary downstream implications - bird migrations will immediately change, and the ecosystem will have geographic pockets of abundance and scarcity due to that. Food pollination also comes to mind. Corporations do not react to emotional pressures [often] - so any link from pesticide/herbicide usage to lack of pollinators will require a round of market disruption. Even then, the answer may not be insects but something like humans or drones to artificially pollinate sustenance plants until unequivocal proof is found that insects were affect by these chemicals.
Because an alarming ecological story comes up, and without evidence or even a rational hypothetical cause, it's immediately blamed on climate change.
Most insects are herbivorous, so rely on plants for food. Global warming (increasing global temperatures, higher atmospheric CO2 concentrations, shorter winters) are conducive to plant growth. So you'd actually expect temperatures increasing by a few degrees to lead to more insects, not fewer.
Loss of continuous habitat is possible, but I'd consider it unlikely. Larger species are more susceptible to that than smaller ones like insects. We would've noticed the loss of biomass there first.
My bet is on pesticides. You state later that Canada and the EU are eco-friendly, therefore speculating that they use less pesticides. But this map (pages 17, 47-49) shows the EU uses more pesticides per hectare than the U.S./Canada, and are only exceeded by China and some South and Central American countries. (The EU uses more pesticides than the U.S. and Canada because it has less arable land but more population. So to feed itself the EU needs to grow more food per hectare.) Pesticide use in kg/ha is down slightly since 1989, but I suspect this is more than offset by development of more effective pesticides.