A big event is coming up in the insect world. Depending on the latitude, starting sometime in April or May, the largest brood of 17-year-old cicadas will emerge from underground in a dozen states, from New York west to Illinois and south to Georgia in the south. This group knows in Roman numerals as 10 for Broad X. For about four weeks, the almond and suburban areas sounded with cicadas whining along the stairs and at the mating taps. After mating, each female will find hundreds of eggs on the branches of a pencil-sized tree.
Then the adult cicadas will die. After the eggs hatch, the new cicada falls from the nymph’s tree and returns to the ground, starting the cycle again. There are probably 3,000 to 4,000 species of cicadas around the world, but the 13- and 17-year periodic cicadas in East America seem to be unique in combining the period of long adolescent development with the emergence of cohesive, mass adults.
These events raise many questions for entomologists and the public. What have the cicadas done underground for 13 or 17 years? What do they eat? Why is their life cycle so long? Why these synchronized? In addition, is climate change affecting this wonder of the insect world? We study Cicadas periodically to understand questions about biodiversity, biodiversity, behavior, and ecology – evolution, natural history, and the geographical distribution of life. We have learned many amazing things about these insects: for example, they can travel in time by changing their life cycle in four-year increments. It is no accident that the scientific name of the periodical 13- and 17-year-old Cicadas is Magicicada, abbreviated to “Magic Cicada”.
As a species, periodic cicadas are older than the forests where they live. Molecular analysis shows that the ancestors of the present Magicicada species divided into two genera about 4 million years ago. About 1.5 million years later, one of those dynasties split again. The resulting three genera form the basis of the modern periodic cicada species group Decim, Cassini and Decula. The first American colonists first encountered periodic cicadas in Massachusetts. The sudden presence of so many insects reminds them of the biblical plague of locusts, a kind of grasshopper.
This is how the name “locust” was mistakenly associated with North America’s cicadas. In the 19th century, notable entomologists such as Benjamin Walsh, C.V. Riley and Charles Marlatt created the wonderful biology of the magazine Seekers. They established that unlike locusts or other grasshoppers, cicadas would not chew leaves, erode crops, or fly over wetlands. Instead, these insects spend most of their lives without sight, growing underground and feeding on tree roots after they reach the age of five.
Their synchronized rises are predictable, occurring in a clockwork schedule of 17 years in the north and 13 years in the south and Mississippi Valley. There are multiple, regional year classes known as broods.
