The Great Southern Brood
Brood XIX is arguably the largest (by geographic extent) of all periodical cicada broods, with records along the east coast from Maryland to Georgia and in the Midwest from Iowa to Oklahoma.
In the map below, cicada symbols are verified records in our database as of February 2021. Gold symbols are from Simon (1988); smaller symbols are records with a lower degree of certainty, and crosses represent records that are considered spurious. Blue symbols are from Marlatt (1923); smaller symbols are records with a lower degree of certainty, and question marks represent records that are considered spurious. Symbols are in layered in the order Database, Simon, Marlatt, and symbols in the upper layers may obscure symbols in lower layers. This map may not be reproduced without written permission.
Illinois presents a particular challenge for understanding periodical cicada biology, because it contains both 13 and 17 year life cycles, all 7 currently recognized species, and five separate broods, some of which include disjunct populations.
Stannard (1975) published a map of all Illinois periodical cicada broods. Standard’s map of Brood XIX includes a small northern disjunct that is instead a part of Brood III, and his delineation of the brood boundary in Adams, Brown, Hancock, and Schuyler includes areas that are also part of Brood III.
In the map below, cicada symbols are verified records in our database as of February 2021. Closed circles are records of the brood from Stannard (1975); open circles represent absences of the brood. The shaded area represents Stannard’s estimation of the brood boundary. This map may not be reproduced without written permission.
Reproductive Character Displacement
An interesting feature of Brood XIX is a striking pattern of reproductive character displacement (RCD). Where Magicicada neotredecim is in contact with another 13-year species, M. tredecim, the dominant male call pitch of M. neotredecim is approximately 1.7 kHz, while outside the contact zone, its call pitch is approximately 1.4 kHz, identical to that of its putative ancestor, M. septendecim; female pitch preferences match (Marshall and Cooley 2000).
Where M. neotredecim and M. tredecim overlap, they exhibit a pattern of reproductive character displacement in calling song pitch and female pitch preferences. Within the zone of displacement, the dominant male call pitch of M. neotredecim is 1.7 kHz, while outside the contact zone, its call pitch is ca. 1.4 kHz, identical to that of its putative ancestor, M. septendecim.
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.
Cooley, J. R., C. Simon, and D. C. Marshall. 2003. Temporal separation and speciation in periodical cicadas. Bioscience 53:151-157.
Lloyd, M., G. Kritsky, and C. Simon. 1983. A Simple Mendelian Model for 13- and 17- Year Life Cycles of Periodical Cicadas, with Historical Evidence of Hybridization Between Them. Evolution 37:1162-1180.
Marlatt, C. L. 1923. The Periodical Cicada. United States Department of Agriculture, Bureau of Entomology Bulletin 71:1-183.
Marshall, D. C., and J. R. Cooley. 2000. Reproductive character displacement and speciation in periodical cicadas, with description of a new species, 13-year Magicicada neotredecim. Evolution 54:1313-1325.
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.
Martin, A., and C. Simon. 1988. Anomalous distribution of nuclear and mitochondrial DNA markers in periodical cicadas. Nature 336:237-239.
Martin, A., and C. Simon. 1990. Differing Levels of Among-Population Divergence in the Mitochondrial DNA of Periodical Cicadas Related to Historical Biogeography. Evolution 44:1066-1080.
Simon, C. 1988. Evolution of 13- and 17-year periodical cicadas. Bulletin of the Entomological Society of America 34:163-176.
Simon, C., J. Tang, S. Dalwadi, G. Staley, J. Deniega, and T. R. Unnasch. 2000. Genetic evidence for assortative mating between 13-year cicadas and sympatric “17-year cicadas with 13-year life cycles” provides support for allochronic speciation. Evolution 54:1326-1336.
Stannard, L. J. 1975. The distribution of periodical cicadas in Illinois. ll. Nat. Hist. Surv. Biol. Notes 91:3-12.