Since my wife's superior vision can spot a dirty car long before I can, I may not qualify to answer the question as to whether the number of insects splattered on the windshield today is increasing or decreasing.
I suspect the latter and will offer two more bits of supporting evidence. As a kid, I would collect lightning bugs by the jar full. Most survived the collection, inspection and release by my little fingers. Although still visible in the summer from a perch on my deck, I suspect collecting a jar full today would be a daunting task.
My second clue is the remembrance of hordes of moths hovering around any outside light. Today I don't see that, and I don't think it is just because I go to bed earlier.
What is happening? Sprays of chemicals may be part of the problem, but my guess is that loss of habitat is a much larger culprit. Fortunately, we can do something about that if we wish.
The first step is to take a long walk in a large woodland or an un-mowed field or meadow. Look for two things. Look for beauty and look for pest damage. Beauty is easy. Pest damage is hard to find unless you are in the thick of an infestation of something like gypsy moths.
Research shows that few of us will spot pest damage until 10 percent of the leaves are damaged. That seldom happens in nature, and noticeable damage need not happen in our gardens if we can learn from our field trip.
Since most insects are specific to the plants they evolved with, one must make a strong case for native plants. Although I have wrestled with a definition of native for a long time, I believe that the most accepted definition includes selections of natives for better landscape qualities.
One fear is that as natives have become more popular, the breeders may swing into action and in their quest for garden beauty may lose some of the characteristics that made the plant desirable to our native insects.
On your hike I hope you also noticed that there were many different plants growing in one community. Diversity of plants favorable to a host of insects is necessary to provide the balance nature uses to sustain itself.
Also, your walk should have suggested that the density of plants in nature usually exceeds what is happening in our yards.
Increasing diversity and planting densities and adding as many native plants as possible will move us closer to a sustainable garden. My gardens will always have plants of foreign origin, but I am increasingly looking for natives to substitute.
What about those pest-free, usually non-native, plants? Too often a non-native insect or disease has sneaked along and thrives without the natural controls. So out comes the sprayer and we are back to our starting point.
Insects are important for pollination, beauty and enjoyment (butterflies), eating other insects and decomposition of organic material. We also must add that they are essential to support many of our songbirds.
Recently, I heard a long-time bird watcher complain that we no longer see tree-fulls of birds like we used to. Ironically, we were standing in a suburban yard that looked like a page out of a combination woods and meadow that was teeming with birds.