Magicicada is the genus of the 13- and 17- year periodical cicadas of eastern North America. These insects display a unique combination of long life cycles, periodicity, and mass emergences. They are sometimes called "seventeen-year locust"s, but they are not locusts; locusts belong to the order Orthoptera.
Four more species follow a 13-year cycle:
Generally, the 17-year cicadas are distributed more in the northern states of the eastern United States, while the 13-year cicadas occur in the southern states.
Periodical cicadas are average-sized for cicadas, but they are slightly smaller than the annual cicada species found in the same regions of the United States. Imagines (or adults) have a size of 2.5 to 3 cm (1 to 1.2 inches). They are black, with red eyes and yellow or orange stripes on the underside. The wings are translucent and have orange veins.
They are harmless insects; they neither bite nor sting. They are not venomous, and there is no evidence that they transmit diseases. They generally do not pose a threat to vegetation, but young plants may be damaged by excessive feeding or egg laying. It is thus advised not to plant new trees or shrubs just before an emergence of the periodical cicadas. Mature plants usually do not suffer lasting damage even by a mass-emergence.
Periodical cicadas are grouped into 30 broods, based on the year they emerge. Broods are numbered using Roman numerals; broods I–XVII are the seventeen-year cicadas, while Broods XVIII–XXX are the thirteen-year cicadas. Some broods are known not to exist, but they are retained in the numbering scheme for convenience. This scheme was put forth by C.L. Marlatt in his classic study of 1907. Since then the actual number of broods has been recognized as 15 rather than 30.
|Name||Nickname||Cycle (yrs)||Last Emergence||Next Emergence||Extent|
|Brood I||The Blue Ridge Brood||17||1995||2012||--|
|Brood III||The Iowan Brood||17||1997||2014||Iowa|
|Brood IV||The Kansan Brood||17||1998||2015||Kansas, Missouri, Oklahoma|
|Brood VII||The Onondaga Brood||17||2001||2018||Upstate New York.1|
|Brood X||The Great Eastern Brood||17||2004||2021||From New York to North Carolina along the East Coast, inland to Illinois and Michigan.2|
|Brood XI||none||17||(2005)||Extinct||Last seen in 1954 in Ashford, CT along Fenton River.|
|Brood XIII||The Northern Illinois Brood||17||2007||2024||Northern Illinois and in parts of Iowa, Wisconsin, and Indiana.3|
|Brood XIV||none||17||2008||2025||Southern Ohio, Kentucky, Tennessee, Massachusetts, Maryland, North Carolina, Pennsylvania, northern Georgia, Western parts of Virginia & W. Virginia, and parts of New York & New Jersey .3|
|Brood XIX||The Great Southern Brood||13||1998||2011||The Midwest to Maryland and Virginia.4|
|Brood XXII||none||13||2001||2014||Louisiana and Mississippi.5|
|Brood XXIII||The Lower Mississippi River Valley Brood||13||2002||2015||--|
| 1. Consists only of M. septendecim.|
2. Largest of all 17-year periodical broods.
3. Premature emergences, or "straggling" occurred in 2003 and 2006.
4. Largest of all 13-year periodical cicada broods.
5. This 13-year brood does not include M. neotredecim.
The nymphs of the periodic cicadas live underground, often at depths of 30 cm (one ft) or more, feeding on the juices of plant roots. They stay immobile and go through five development stages before constructing an exit tunnel in the spring of their 13th or 17th year. These exit tunnels have a diameter of about 1–1.5 cm (½ in.)
The nymphs emerge on a Spring evening when the soil temperature at about 20 cm depth is above 17 °C (63 F). In most years, this works out to late April or early May in far southern states, and late May to early June in the far northern states. Emerging nymphs climb to a suitable place on the nearby vegetation to complete their transformation into an adult cicada. They molt one last time and then spend about six days in the leaves waiting for their exoskeleton to harden completely. Just after this final molt, the teneral adults are white, but darken within an hour.
The nymphs emerge in large numbers at about the same time, sometimes more than 1.5 million individuals per acre (>370/m²). Their mass-emergence is a survival trait called "predator satiation": for the first week after emergence, the periodic cicadas are an easy prey for reptiles, birds, squirrels, cats, and other small and large mammals. The cicadas' survival mechanism is simply to overwhelm predators by their sheer numbers, ensuring the survival of most of the individuals. It has been hypothesized that the emergence period of large prime numbers (13 and 17 years) is also a predatory avoidance strategy adopted to eliminate the possibility of potential predators receiving periodic population boosts by synchronizing their own generations to divisors of the cicada emergence period.
Adult periodical cicadas live only for a few weeks—by mid-July, all have disappeared. Their short adult life has one sole purpose: reproduction. The males "sing" a mating song; like other cicadas, they produce loud sounds using their tymbals. Receptive females respond to the calls of conspecific males with timed wing-flicks, which attract the males for mating. The sounds of a "chorus"—a group of males—can be deafening and reach 100 dB.
Both males and females can mate multiple times, although most females seem to mate just once. After mating, the female cuts V-shaped slits in the bark of young twigs and lays approximately 20 eggs in each, for a total of 600 or more eggs. After about six to ten weeks, the eggs hatch and the newborn nymphs drop to the ground, where they burrow and begin another 13 or 17-year cycle. The carcasses of periodic cicadas decompose on the ground, providing a resource pulse of nutrients to the forest community.
Periodic cicadas unwelcome visitors to Crawford County village; Noisy pests: These insects often are called locusts
Jul 13, 2002; For the past month, Illinois' Crawford County village of Flatrock has been overrun by a noisy, messy periodic pest. The emergence...