Q. When will the periodical cicadas emerge?
A. They are expected in mid-May, but will emerge when soil temperatures are in the mid-60s, F.

Q. What is their emergence range?
A. They will be central to the mid-Atlantic area, and extend from Georgia to Indiana to New Jersey, appearing in some 15 states. [Note: Click Here to see a detailed Brood X map. Or,
Click Here to see a small-scale composite map of more brood ranges. These and other detailed brood maps can be found at the Periodical Cicada Page, from the Univ. of Michigan Museum of Zoology. REF: http://insects.ummz.lsa.umich.edu/fauna/michigan_cicadas/Periodical/Index.html]

Q. Periodical cicadas were in Virginia last year. What does that mean?
A. Although these cicadas take 17 years for their life cycle, different broods appear each year in the eastern United States. The 2004 brood is known as Brood X (Roman numeral "X" = ten). There are some twenty broods, and in the southern states, the broods take only 13 years to mature.

Q. Are all the periodical cicadas only one species?
A. No, before 1962, science recognized a few species. A comprehensive research effort recognized the presence of three northern species and three southern species, separated by song and coloration differences. Just a few years ago, a seventh species was described because of its distinct song.

Q. How many cicadas are expected?
A. Throughout their range, tremendous numbers, exceeding trillions. In perfect conditions of heavy forests, there may be as many as 1.5 million per acre.

Q. Are they harmful to humans in any way?
A. Cicadas do not bite or sting. Small trees may be severely damaged by the egg-laying of female cicadas, so ornamental plantings should be covered with bird netting or similar protective coverings when periodical cicadas are on the wing.

Q. Are they beneficial in any way?
A. Yes, there are a number of benefits. Their tunnels aerate the soil, they conduct a natural pruning of large trees, they provide food for many animals, including moles, mice, opossums, raccoons, bears, birds, snakes, lizards and fish, and upon death they provide a large dose of nitrogen for the soil.

Q. What do their songs sound like?
A. A northern species has a song that sounds much like the word "pharoah." Other species have a sound that seems to be a series of buzzes and clicks at the same time. Individuals also have a squawk or alarm sound when they are grabbed. [Click here for Audio File Samples]

Q. How do they determine when to emerge?
A. Scientists are unsure how cicadas can "calculate" the passage of 17 years. It may relate to the recognition of annual moisture or dryness cycles, combined with gaining appropriate size. Perhaps hormones develop at the correct time to stimulate emergence.

Q. I've heard these insects called "locusts." Why?
A. When settlers first came to the United States from the Old World, they encountered 17-year cicadas and thought them to be the locusts (grasshoppers) that migrated in large numbers. The term "locusts" have remained a common though inaccurate terminology for periodical cicadas.

Q. Will the noise of the cicada songs be deafening, and how is it made?
A. The sound is made with structures known as tymbals which are located on the sides of the first abdominal segment, near the top just behind where the hindwings attach. Large muscles contract, causing the tymbal surface to bend inwards which produces a vibrating click. These vibrating clicking noises are enhanced by a large air chamber that extends well into the abdomen. Repeated contractions by thousands of cicadas can create a spectacular din. Females chose the male that interests them with a flick of their wings which stimulates the male to come closer. [Click here for an image showing the tymbals]

Q. Will the noise of the cicadas bother us at night?
A. No, periodical cicadas do not sing at night.

Q. Does the Smithsonian Institution have a collection of cicadas?
A. Yes, over many years, cicadas have been collected by or donated to the Smithsonian. There are some 3000 species of cicadas in the world, and Smithsonian collections harbor some 138 drawers of these, of which about 13 are devoted to periodical cicadas.

Q. Are all 3000 world cicada species represented in the Smithsonian collection?
A. No, but there is a wealth of specimens from fingernail size to those with eight-inch wing spans. The Smithsonian Cicada Collection averages some 150 specimens per drawer, and the total figures to about 414 square feet of space.

Q. Why does the Smithsonian need so many specimens of cicadas or other insects in general?
A. The Smithsonian Entomological Collection is arguably the largest in the world, and harbors a collection of some 32 million specimens. Because an average of 7000 new species of insects are named annually by worldwide researchers, major insect collections are critical for such work. Label data as well as specimens can provide essential information in proper analyses of distribution, parasitism, predation, plant and plant product associations, venoms for disease control, and potential products for humankind. In recent decades, researchers have recognized that insects harbor more natural chemicals for use by humans than do all plant species.

Q. But why so many specimens of periodical cicadas?
A. As noted earlier, periodical cicadas are composed of seven known species. This would not have been recognized without song recordings and the examination of collection specimens, including those at the Smithsonian. Predictions of large emergences of these insects is served well by collection analysis, and helps humans in many ways, from gardeners wishing to protect ornamental tree plantings, to wedding planners not wishing to share punch bowls with large insects during outside ceremonies.

Q. What are the cicada species expected in Brood 10?
Magicicada septendecim, Magicicada cassini, and Magicicada septendecula

[Note: For the Science in the News Exhibit Case - Magicicada tredecim, one of the 13-year cicadas and sister species to the northern Magicicada septendecim, was substituted because Smithsonian collections were limited in numbers of Magicicada septendecula specimens.]

Q. What are the higher level taxonomic classifications for the three cicada species expected in Brood 10?

A. Well first, taxonomy, or "taxonomic classification," is the orderly classification of living things based on seven major zoological categories or levels in hierarchical order as Kingdom, Phylum, Class, Order, Family, Genus, and Species. The higher level taxonomies for the three Brood X species are:

Animalia
   Arthropoda
       Insecta
          Homoptera
              Cicadidae
                     Magicicada septendecim
                     Magicicada cassini
                     Magicicada septendecula

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