Windshield Phenomenon
I was sharing a cup of tea with a friend, discussing garden successes and failures when she hit me with this verbal poke in the eye: “Did you notice, when you returned from that trip to Columbus, that your windshield was NOT splattered with insects?”
So I checked, and yes, it is a thing.
Entomologists call it the windshield phenomenon. Wolfgang Wägele, director of the Leibniz Institute for Animal Biodiversity in Bonn, Germany confirms - drivers spend less time scraping and scrubbing.
Though observations about splattered bugs aren't scientific, few reliable data exist on the fate of important insect species. 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 non-charismatic species," which most insects are, says Joe Nocera, an ecologist at the University of New Brunswick in Canada.
Now, 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%. 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.
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.
Changes in land use surrounding the reserves are probably playing a role. As fields expand and hedgerows disappear, the isolated islands of habitat left can support fewer species. Increased fertilizer on remaining grazing lands favors grasses over the diverse wildflowers that many insects prefer. And when development replaces countryside, streets and buildings generate light pollution that leads nocturnal insects astray and interrupts their mating.
Neonicotinoid pesticides, already implicated in the widespread crash of bee populations, are another prime suspect. Introduced in the 1980s, they are now the world's most popular insecticides, initially viewed as relatively benign because they are often applied directly to seeds rather than sprayed. But because they are water soluble, they don't stay put in the fields where they are used. Nectar and pollen from wildflowers next to treated fields can have higher concentrations of neonicotinoids than the crop plants. Allowable levels of the compounds may not kill honeybees directly, but they do affect the insects' abilities to navigate and communicate. Researchers found similar effects in wild solitary bees and bumble bees.
Less is known about how those chemicals affect other insects, but new studies of parasitoid wasps suggest those effects could be significant. Those solitary wasps play multiple roles in ecosystems—as pollinators, predators of other insects, and prey for larger animals.
It's a global concern. Across North America and Europe, species of birds that eat flying insects, such as larks, swallows, and swifts, are in steep decline. Habitat loss certainly plays a role, but the obvious factor that ties them all together is diet.
The message is worth repeating -- paying attention to what E. O. Wilson calls "the little things that run the world" is something we should all do – otherwise we can cause massive damage to biodiversity—damage that harms all of us.