The Stories that Insects Tell

Imagine taking an American history class where many of the important events were reduced to mere footnotes or skimmed over entirely.  Anyone taking the class would be shocked at this notion—I mean, the Civil War was a big deal after all!  When you look at a different field of study—biology—such a trend has surprisingly occurred, with insects getting the short end of the stick.  Insects are the most diverse and abundant animals on the planet and make up roughly 70% of the 1,000,000+ described animal species.  Yet, many introductory biology textbooks skim over insects (and invertebrates in general) in favor of more charismatic megafauna—a trend that has only gotten worse over time.  Insects may be small, but they serve crucial roles in the world around us from pollinating plants to serving as the base of food webs.  Appropriately, E.O. Wilson referred to insects as “the little things that run the world” in his famous call for their conservation.  It’s difficult to conserve these little creatures that run the world when so few people really get to know them.  

With their sheer diversity and abundance,  knowing the insects also helps us better understand the world, and everyday life, around us.  Getting to know the many different insects is a bit like learning a foreign language.  Travel to an exotic country where you don’t speak the local tongue and you’d have a hard time understanding the everyday happenings around you.  As you picked up words and phrases of that foreign language, things will become easier to understand.  Along these lines, if you can recognize the insects around you, it helps interpret the stories they tell.  Truly knowing your insects is like possessing an all-powerful decoder ring to the untold stories that surround us.  

Let’s look to flies to illustrate this point.  To many folks, a small fly found in their home is assumed to be a fruit fly, and a large fly, a house fly.  But there are dozens of different flies that commonly show up indoors—each with their own story to tell.  Fungus gnats hint at overwatered houseplants, moth flies indicate build-up in a bathtub drain, and metallic blow flies can alert you to a mouse trap in need of checking.  Outdoors, other species of flies can provide clues that gauge water quality, indicate the presence of specific plants, or solve crimesbut only if one knows how to interpret their clues.  If a picture is worth a thousand words, I’d argue that a properly identified insect is worth even more.  

The unusual fly species, Asteia baeta. At only 2mm long, these flies can readily be mistaken for fruit flies to the naked eye. Photo Credit: PJ Liesch, UW Insect Diagnostic Lab

This holiday season, my own love of insects led to a scientific discovery that would have gone unrecognized in most households.  A day after setting up our “real” Christmas tree, I noticed several tiny flies at the windows of our home.  My curiosity was piqued and like any good detective, some sleuthing was needed.  I recall an undergraduate professor telling the class, “a biologist without a notebook is off duty” to which I’d add, “an entomologist without vials is off duty”.  So now I was off, vials in hand, on an insect hunt in my own house.  Once the specimens were examined under the microscope, I recognized the flies as a rare species (Asteia baeta) from the poorly-known family Asteiidae.  There isn’t much written about these flies, but they’re known to be associated with fungi, vegetation, and tree sap, which told me that the new Christmas tree was the source.  These flies have only been spotted in Wisconsin a few times and no preserved specimens exist for that family in the Wisconsin Insect Research Collection (I’ll be donating some soon).  Looks like our Christmas tree came with it’s own entomological story to tell this year—I’m glad I knew how to listen.

The source of the unusual flies—apparently our cat wanted to try and hunt for them as well. Photo Credit: PJ Liesch