Around the time when the puffy, spherical clusters of seeds appear on dandelions, male hummingbirds are engaging in their courtship flights, and hoards of black flies arrive when the air become humid, June bugs make their annual appearance during the evening around porch lights, street lamps, and well illuminated windows.
When indoors at this time of year after dark, it is common to hear the sound of this hefty, hard-shelled bug repeatedly flying into a screen, continuously beating its wings against a window pane, or buzzing around an outside light, as if attempting to get directly into the source of illumination.
June bugs form a group of slightly elongated, brown beetles that average just over three-quarters of an inch in length. Like all beetles, June bugs have two sets of wings; a hind set used for flight that folds precisely over its back when not in use, and a stiff, chestnut-colored front set that covers its flight wings, and helps to reinforce its already hard exoskeleton. While the hind set of wings enables the Jung bug to fly, this set of transparent appendages is not as large and powerful as the wings of numerous other insects. Researchers have noted that the June bug is incapable of flapping its wings at the same high rate as many other flying insects in our region. This reduces the amount of lift produced by these wings, and limits this bug’s flying ability. Like the bumble bee, the June bug is barely able to become and remain airborne, however, because an adult does spends very little time in the air during the course of its life, this skill has failed to evolved into a more effective talent.
At this time of year, as the sun sets and the humidity increases, making odors more prominent, males start their aerial search for the scent trail produced by a nearby female. When an adult female is ready to have her eggs fertilized, she takes to the air for only a short flight, during which time she emits a certain chemical that advertises her receptive condition. Upon detecting this specific substance, a male quickly follows the invisible trail back to its source and begins the process of mating with her.
Researchers are still unsure why June bugs are so strongly attracted to light. Since there are no chemical emissions produced by an incandescent bulb, or a CFL, especially considering that it would often have to pass through a solid pane of window glass, it is a mystery why male June bugs react the way they do when a source of light is placed in their general vicinity. However, when exposed to a source of light, it is not uncommon for a June bug to exhaust itself by continuously flying into a window, occasionally collapsing on the ground and experiencing difficulty getting back into the air. Should this hefty bug land on its rounded back, it must struggle to right itself. Some finally die of exhaustion, but most can recover and fly off, or work their way into the top layer of soil until the next evening.
A struggling June bug on the ground becomes an easy target for smaller predators, such as a toad, ermine, raccoon, or any other nocturnal creature with a fondness for a meaty bug. Those individuals that died of exhaustion are quickly eaten by birds, like the crow, blue jay or robin early the following morning.
After mating, an adult June bug is capable of living for several more weeks to a month before it eventually dies. During this time, the adult is known to consume the foliage of certain broad-leaf trees, like the maples. Since the population of June bugs in any given section of forest is never very high, the overall damage which the adults inflict on trees is considered very minor. Also, because the mouth of this bug is adapted for chewing on leafy matter, rather than meat, it is unable to bite a human, or any other mammal that it may encounter. While some individuals claim to have been attacked and bitten by a June bug, experts believe that these incidents are the result of a June bug flying at full speed on the track of a potential mate and accidentally running into that person. Given the size of an adult, and the density of its exoskeleton, an impact could produce a stinging sensation to an area of unprotected skin that could easily be mistaken for a bite.
The environmental harm caused by a June bug comes from the ravenous appetite of its worm-like, larval state, known as a grub. After its eggs hatch in mid-summer, the white-colored immature insect burrows down into the soil an inch or two where it begins to feast on the roots of certain herbaceous plants, especially grasses. Damage to lawns can be noted during a brief dry period, as a patch of grass that has had much of its root system destroyed by several grubs, quickly succumbs to the lack of moisture and turns brown.
This has been a good year for June bugs, as there have been many of these insects pounding on my windows after dusk. Eventually, these aerial assaults diminish in intensity as the month progresses, just as the population of black flies decreases as the hot, dry weather of summer arrives. I am especially looking forward to the latter.
Photo by Wikimedia user Patrick Coin.