A National Geographic Society sponsored project
The periodical cicadas (Magicicada spp.) of Eastern North America have the potential to answer general questions concerning speciation, species boundaries, and postglacial biogeography. Many of these questions are most effectively addressed with accurate maps of periodical cicada emergences. Yet although crude maps of periodical cicadas have existed for over a century, many current maps of these insects are only modernizations of these earlier maps, and their inaccuracies or errors limit their utility.
Modern transportation, highly accurate base maps, GPS technology, and a better understanding of periodical cicada biology provide unprecedented opportunities for accurately mapping Magicicada populations. To date, we have surveyed and mapped over 10,000 localities within periodical cicada emergences, using detailed base maps and GPS technology, such as the custom GPS datalogger pictured below.
Why map periodical cicadas?
Periodical cicada emergences capture popular attention. When European colonists first encountered these insects, they were puzzled. Emergences seemed unpredictable, and over the years, the insects appeared to move across the landscape as if they were plagues of locusts.
In response to this confusion, natural historians began to record the dates and locations of emergences. Early efforts to compile this information into maps demonstrated that there was a clear, predictable pattern to emergences: In any given area, adult periodical cicadas emerge only once every 13 or 17 years, they are consistent in their life cycles, and populations (or “broods”) in different regions are not synchronized.
Currently there are 7 recognized species, 12 distinct 17-year broods, and 3 distinct 13-year broods, along with 2 known extinct broods, found east of the Great Plains and south of the Great Lakes, to the Florida Panhandle. From this bewildering mix, several patterns have emerged:
- Most of the complex spatial and temporal relationships of periodical cicada broods and species must be less than 10,000 years old, because much of the current range of periodical cicadas in the eastern, Appalachian, and Midwestern U.S. would have been unsuitable for periodical cicadas during and for substantial periods following the Wisconsin glaciation (see Watts 1983; Webb 1981).
- Permanent life cycle changes lead to species formation, while temporary life cycle changes lead to brood formation in Magicicada. Each Magicicada species is most closely related to another with a different life cycle, a pattern that suggests multiple speciation events involving permanent life cycle change (Cooley et al. 2001; Marshall and Cooley 2000; Marshall et al. 2003; Simon et al. 2000). By contrast, environmental miscues of life cycles have the potential to form broods without permanently altering life cycles (Kritsky and Simon 1996; White and Lloyd 1979; Young 1958).
- Geographic distributions hold the key to understanding life cycle change in Magicicada. One instance of allochronic speciation, the formation of the 13-year species M. neotredecim from the 17-year species M. septendecim was identified on the basis of a striking biogeographic pattern of reproductive character displacement (Cooley et al. 2001; Marshall and Cooley 2000; Simon et al. 2000). The temporal and biogeographic relationships of 17-year broods suggest a scheme in which geographically adjacent broods are more closely related than distant broods (Alexander and Moore 1962; Marlatt 1923; Young 1958) and in which broods gave rise to other broods via simple 1- or 4- year temporary life cycle accelerations (Lloyd and Dybas 1966; Simon and Lloyd 1982).
Although maps are an important tool for addressing such questions, most current distribution maps of periodical cicadas trace their ancestry to C. M. Marlatt’s (1923) 19th century compilations of historical emergence records. Unfortunately, these maps and their derivatives tend to overestimate periodical cicada range limits, so they can provide misleading answers to important questions (Marshall 2001). The questions involved are not trivial: Periodical cicada responses to deglaciation may provide insights into the possibility that they are useful for monitoring forest and ecosystem health (see Cooley et al.; Cooley et al. 2004), while the biogeography of broods and species may provide critical insights into the general nature of species, speciation processes, and gene flow between species.
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Cooley, J. R. 2004. Asymmetry and mating success in a periodical cicada, Magicicada septendecim (Hemiptera: Cicadidae). Ethology 110:745-759.
Cooley, J. R. 2007. Decoding Asymmetries in Reproductive Character Displacement. Proceedings of the Academy of Natural Sciences of Philadelphia 156.
Cooley, J. R. 2015. The distribution of periodical cicada (Magicicada) Brood I in 2012, with previously unreported disjunct populations (Hemiptera: Cicadidae). The American Entomologist 61:52-57.
Cooley, J. R., G. S. Hammond, and D. C. Marshall. 1998. Effects of enamel paint on the behavior and survival of the periodical cicada, Magicicada septendecim (Homoptera) and the lesser migratory grasshopper, Melanoplus sanguinipes (Orthoptera). Great Lakes Entomologist 31:161-168.
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Cooley, J. R., G. Kritsky, D. C. Marshall, K. B. R. Hill, G. J. Bunker, M. L. Neckermann, J. Yoshimura, J. E. Cooley, and C. Simon. 2016. A GIS-based map of periodical cicada Brood XIII in 2007, with notes on adjacent populations of Broods III and X (Hemiptera: Magicicada spp.). The American Entomologist 62:241-246.
Cooley, J. R., G. Kritsky, J. D. Zyla, M. J. Edwards, C. Simon, D. C. Marshall, K. B. R. Hill, and R. Krauss. 2009. The distribution of periodical cicada Brood X. The American Entomologist 55:106-112.
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Cooley, J. R., D. C. Marshall, A. F. Richards, R. D. Alexander, M. D. Irwin, J. R. Coelho, and C. Simon. 2013a. The distribution of periodical cicada Brood III in 1997, with special emphasis on Illinois (Hemiptera: Magicicada spp.). The American Entomologist 59:9-14.
Cooley, J. R., D. C. Marshall, and C. Simon. 2004. The historical contraction of periodical cicada Brood VII (Hemiptera: Cicadidae: Magicicada). Journal of the New York Entomological Society 112:198-204.
Cooley, J. R., M. L. Neckermann, G. J. Bunker, D. C. Marshall, and C. Simon. 2013b. At the limits: Habitat suitability modeling of Northern 17-year periodical cicada extinctions (Hemiptera: Magicicada spp.). Global Ecology and Biogeography 22:410-421.
Cooley, J. R., C. Simon, C. Maier, D. C. Marshall, J. Yoshimura, S. M. Chiswell, M. D. Edwards, C. W. Holliday, R. Grantham, J. D. Zyla, R. L. Sanders, M. L. Neckermann, and G. J. Bunker. 2015. The distribution of periodical cicada (Magicicada) Brood II in 2013: Disjunct emergences suggest complex origins. The American Entomologist 61:245-251.
Cooley, J. R., C. Simon, and D. C. Marshall. 2003. Temporal separation and speciation in periodical cicadas. Bioscience 53:151-157.
Cooley, J. R., C. Simon, D. C. Marshall, K. Slon, and C. Ehrhardt. 2001. Allochronic speciation, secondary contact, and reproductive character displacement in periodical cicadas (Hemiptera: Magicicada spp.): genetic, morphological, and behavioural evidence. Molecular Ecology 10:661-671.
Fontaine, K. M., J. R. Cooley, and C. Simon. 2007. Evidence for paternal leakage in hybrid periodical cicadas (Hemiptera: Magicicada spp.). PLos One 9:e892.
Ito, H., S. Kakishima, T. Uehara, S. Morita, T. Koyama, T. Sota, J. R. Cooley, and J. Yoshimura. 2015. Evolution of periodicity in periodical cicadas. Scientific Reports 5:14094.
Koyama, T., H. Ito, T. Fujisawa, H. Ikeda, S. Kakishima, J. R. Cooley, C. Simon, J. Yoshimura, and T. Sota. 2016. Genomic divergence and lack of introgressive hybridization between two 13-year periodical cicadas supports life-cycle switching in the face of climate change. Molecular Ecology 25:5543-5556.
Koyama, T., H. Ito, S. Kakishima, J. Yoshimura, J. R. Cooley, C. Simon, and T. Sota. 2015. Geographic body size variation in the periodical cicadas (Magicicada): Implications for life cycle divergence and local adaptation. Journal Of Evolutionary Biology 28:1270-1277.
Kritsky, G., and S. Simon. 1996. The unexpected 1995 emergence of periodical cicadas (Homoptera: Cicadidae: Magicicada spp.) in Ohio. Ohio Journal Of Science 96:27-28.
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Marshall, D. C. 2001. Periodical cicada (Homoptera: Cicadidae) life-cycle variations, the historical emergence record, and the geographic stability of brood distributions. Annals Of The Entomological Society Of America 94:386-399.
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Marshall, D. C., J. R. Cooley, R. D. Alexander, and T. E. Moore. 1996. New records of Michigan Cicadidae (Homoptera), with notes on the use of songs to monitor range changes. Great Lakes Entomologist 29:165-169.
Marshall, D. C., J. R. Cooley, and K. B. R. Hill. 2011a. Developmental plasticity in Magicicada: Thirteen year cicadas emerging in seventeen and twenty-one years (Hemiptera: Cicadidae). Annals Of The Entomological Society Of America 104:443-450.
Marshall, D. C., J. R. Cooley, and C. Simon. 2003. Holocene climate shifts, life-cycle plasticity, and speciation in periodical cicadas: A reply to Cox and Carlton. Evolution 57:433-437.
Simon, C., and M. Lloyd. 1982. Disjunct synchronic population of 17-year periodical cicadas: Relicts or evidence of polyphyly? Journal of the New York Entomological Society 110:275-301.
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Smits, A., J. R. Cooley, and E. Westerman. 2010. Twig to Root: Eggnest density and underground nymph distribution in a periodical cicada (Hemiptera: Magicicada septendecim L.) Entomologica Americana 116:73-77.
Sota, T., S. Yamamoto, J. R. Cooley, K. B. R. Hill, C. Simon, and J. Yoshimura. 2013. Different histories of divergence into 13- and 17-year life cycles among three periodical cicada lineages. Proceedings of the National Academy of Sciences of the United States of America 110:6919-6924.
Tanaka, Y., J. Yoshimura, C. Simon, J. R. Cooley, and K.-i. Tainaka. 2009. The Allee effect in the selection for prime-numbered cycles in periodical cicadas. Proceedings of the National Academy of Sciences of the United States of America 106:8975-8979.
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