Michigan residents often hear the distinctive, loud buzz of summer insects and wonder if the state is home to the same cicadas that periodically emerge in massive swarms. The answer is yes; cicadas are a regular part of Michigan’s insect fauna, appearing in different forms and on different schedules. Understanding the specific types of cicadas present and their unique life cycles clarifies what to expect and when.
Yes, Cicadas are Found in Michigan
Michigan hosts two broad categories of cicadas, each with a distinct appearance and emergence pattern. The most commonly encountered are the annual cicadas, often called Dog-Day Cicadas, because their presence peaks during the hottest part of the summer. These insects are characterized by thick, robust bodies, typically one to one-and-a-half inches in length, displaying green and brown markings.
Annual cicadas have a life cycle lasting between two and eight years, yet adults emerge every year. This yearly appearance happens because the life cycles of the various Dog-Day species are not synchronized, meaning a portion of the population surfaces each summer. They spend the vast majority of their time underground as nymphs, feeding on sap from tree roots before their final emergence.
The other type found in the state is the periodical cicada, belonging to the genus Magicicada and known for its synchronized, mass emergences. These cicadas are visually distinct from their annual relatives, possessing black bodies accented with red coloration and prominent red eyes. Periodical cicadas follow a life cycle of either 13 or 17 years, emerging in massive groups called broods that are isolated geographically.
Michigan is home to populations of the 17-year periodical cicadas, primarily Brood X, which last emerged in 2021 in southeastern counties like Washtenaw and Oakland. Another significant group, Brood XIII, is sometimes observed in the extreme southwest corner of the state near the Indiana border.
Understanding the Emergence Schedule
The annual cicadas adhere to a yearly schedule, with adults typically appearing in mid-to-late summer, usually between July and September. Although an individual Dog-Day Cicada may spend several years developing as a nymph, the staggered nature of their emergence ensures a new generation of adults is present every season. The timing often coincides with the “dog days” of summer, lending the insects their common name.
The emergence of the massive periodical cicada broods is dictated by a strict multi-year cycle, making their appearance a rarer event. These insects spend 17 years underground, with the nymph stage feeding on plant root fluids throughout the subterranean period. The final stage of emergence is triggered by an environmental cue: the soil temperature reaching a consistent 64 degrees Fahrenheit.
This temperature threshold is usually met in Michigan between mid-May and early June, initiating the synchronized ascent of billions of nymphs. Once above ground, the adults have a short lifespan of four to six weeks, dedicated entirely to mating and egg-laying before they die. The eggs hatch, and the new nymphs drop to the ground, immediately burrowing in to begin the next 17-year cycle. The geographical locations of the broods are well-mapped.
Managing the Noise and Misconceptions
The most noticeable characteristic of cicadas is the intense, buzzing sound produced by the males, a mating call generated by vibrating membranes on their abdomen called tymbals. This sound can be surprisingly loud, sometimes reaching volumes between 90 and 100 decibels during peak activity. The noise is a normal part of the summer environment and lasts for the few weeks the adults are alive.
Despite the loud sound and large numbers during a periodical emergence, cicadas are harmless to humans and pets. They do not bite or sting, and they pose no structural threat to homes or property. The primary form of damage they inflict is on young trees, where female cicadas use an ovipositor to cut small slits in the bark of twigs to lay their eggs.
This egg-laying activity can cause the tips of small branches to die back, a phenomenon that acts as a natural pruning process. A persistent misconception is the confusion between cicadas and locusts, a term often incorrectly applied to the periodical broods, such as “17-year locusts.” True locusts are a type of grasshopper that can form migratory swarms and cause immense crop damage, belonging to a completely different insect order.