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magicada species

Cicadas in the Genus Magicada

If you have been on a trip to the southern or eastern Great Lakes region you have heard them and probably seen them. This summer eastern Iowa, northern Illinois, southern Wisconsin, and the southern edge of Lake Michigan into Indiana and Michigan will be inundated by Brood XIII. The brood is actually a synchronized emergence of 3 species of periodical cicadas in the genus Magicada. Each brood is numbered according to its emergence year (13 or 17) and to location. Brood XIII is on a 17 year emergence cycle. It is very difficult to tell the 3 species of Magicada apart, but Magicada cicadas usually have red eyes and are easy to separate from the grey eyed annual cicadas species.

Magicada species comparison

Numbers remain high in the southern Great Lakes area because forest and riparian river edge habitats remain intact in the suburbs and within parks and preserves. Cicadas songs sound similar to those of katydids and crickets (family Orthoptera), however, cicadas are in the family Homoptera and are closely related to aphids and leafhoppers. Even though these insects live for 17 years, we don't see them, because most of their lives they live under the ground as juvenile nymphs. Millions of adults emerge and reproduce in just a few weeks in late May and early June. When they are ready to molt into adults the nymphs use their powerful front tarsi to dig out of the soil. They climb to a suitable perch and molt one last time into winged adults. Only the males call to attract females. After mating each female will lay about 600 eggs in slits in tree branches and then they die. The young cicadas hatch and feed on tree sap as they crawl down and burrow underground to feed first on grass and then tree roots for the next 17 years. The nymphs shed their skins as they feed and grow. But before you run for the bug killer consider that the metabolism of each cicada is very slow if it takes it 17 years to develop, so even large numbers of insects (30 per square foot) are unlikely to kill or damage healthy trees. The slits made by adults will prune small twigs and branches, but this is usually ecologically beneficial to the forest. Small trees should be wrapped with foil so the females cannot climb them.

emerging nymphs

Models have shown that only insects with life-cycles longer than 10 years can become synchronized (Hoppensteadt & Keller 1976). Several hypotheses have been suggested to explain the synchronization of broods. The most commonly suggested is the "predator satiation" hypothesis. Cicadas are a highly nutritious food source and immediately after emergence the new soft bodied adults (tenerals) cannot fly or move. Predators including wasps, birds, lizards and snakes, and many mammals including rodents, weasels, coyotes, and yes, even humans will feed on the adults. (Descriptions liken the taste to canned asparagus with notes of almond or peanutbutter). But with so many adults emerging at once predators will only be able to eat a fraction each day and those that survive will go onto to produce the next generation.

The cicadas you hear in the late summer are all annual cicadas and are easily differentiated by their loud intermittent call. In Northeastern Wisconsin the cicada most often heard in the afternoon is Tibicen canicularis. These, and 7 of the 9+ species of cicadas found in WI are commonly called annual cicadas because even though they have 2-4 year lifecycles, adults emerge every year because the broods are not synchronized.

Cicada Resources

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Last updated on April 15, 2014