Insects readily make their presence known at two points during the year - the spring when the aquatic insects emerge to mate, and summer when the more terrestrial bugs set out to do the same. The most noticeable of these warm weather wonders are either visually interesting, like the fireflies, butterflies, and moths or produce a cacophonous chorus like the katydids, crickets, and cicadas.
Summer wouldn’t be summer without the regular emergence of fireflies. Easily the most recognized bioluminescent set of species, fireflies’ characteristic green strobe illuminates the night from July to September. The light is a chemical reaction that, unlike most of the ways we can produce artificial light, produces very little heat. Fireflies use special organs to transport oxygen into their abdomens where it powers this unique reaction.
The other common nighttime fliers are moths. Moths are highly specialized creatures that can navigate in near darkness using a variety of methods from active echolocation to the acute senses of smell and, believe it or not, acute vision. Most moths have surprisingly good nighttime vision which allows them to locate their preferred flowers or other food sources. Moths can actually slow down how quickly they see things, allowing their eyes and brain to perceive a less-detailed but still perceptible world in nearly complete darkness.
The daytime cousins of moths, butterflies, make for pleasant flower visitors throughout the summer. Butterflies, like most birds, see well into ultraviolet wavelengths of light which makes things like flowers and freshly laundered clothes fluoresce brightly in daylight. All but one of our butterflies stay here in the winter in some form. Monarchs migrate to Mexico, but the remaining 132 or so species of butterflies left in the state find some sort of alcove to tuck into for the long winter ahead.
Summer has a much different night soundtrack than the spring. Where the amphibians are the major contributors to the auditory experience of spring evenings, insects are the main source in the warmer months.
The commotion created by crickets and katydids comes from tiny structures on their wings. One wing has tiny ridges and the other a hardened scraper that moves along the ridges “playing” the wing like a washboard. The process, called stridulation, produces the distinctive chirping sound of crickets and the eponymous sounds of the katydid.
Stridulation Organ, Illustration by Charles Darwin
The other sound filling the nighttime air during the summer is the unmistakable tremor of the cicadas. In their case the structures that create their particular sound come from a series of membranes called tymbals that resemble the ones in our ears. Though instead of allowing them to hear things, the membrane causes a sound wave that resonates throughout their entire body and in some species reaches 100 or more decibels in volume.
The intrepid insect investigator can choose from numerous destinations to explore and find these summer bugs.
Millbrook Marsh Nature Center is great place to find all manner of bugs. Guests can spend an afternoon looking for an assortment of summer bugs in their native pollinator gardens. The pollinator gardens are maintained by a dedicated volunteer group and showcase a wide variety of native flowering plants that attract, as the name implies, pollinators. The gardens are located just past the start of the trail at the parking lot. From there a guest can follow one of the grass paths and open sections of boardwalk to glimpse butterflies busily flitting about looking for food. The monarchs’ favorite plant, milkweed, is grown in abundance across the non-marsh meadows and open fields making this prime viewing for the well-traveled species.
As the evening approaches, the landscape is filled with the night-time sounds of our more vocal insects. While parks such as Millbrook Marsh are closed at dusk, the Spring Creek Canyon offers an opportunity to explore in the twilight hours. Guests can park at the western end of the trail on Rock Rd. and follow the single path as it meanders along Spring Creek. The combination of cicadas and running water is a wonderful soundtrack to spend an evening relaxing to. Past the Shiloh Rd. access area, the trail transitions into an old dirt road. There is a bench that can be found on the stream-side of the trail about a quarter mile past the parking lot that is dedicated to Martha Goodwin and perfect for relaxing and enjoying the sights and sounds of nature from.
A little further afield, a similar trail near the water is the Lower Trail. The trail itself can be accessed at any number of the “stations” along its length. On warm summer nights guests looking for the sounds of crickets and water can enter at the “Flowing Springs” and “Mount Etna” stations. These stations are more remote and offer excellent excursions into the forests on either side of the Frankstown Branch of the Juniata River. The “Cove Dale,” “Williamsburg,” and “Grannas” stations offer the ability to see vast open fields of fireflies and a more classic rural Pennsylvania feel.