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Periodical cicadas, known for strict life-cycle lengths of 13 or 17 yr, actually exhibit developmental plasticity in cycle length. This variation tends to occur in 1- and 4-yr increments for both life-cycle types, with the largest events involving 4-yr accelerations of the 17-yr species. The pattern has stimulated hypotheses to explain brood formation and life-cycle evolution, but most of the evidence is anecdotal. We present the first quantitative evidence confirming that a site with a 4-yr acceleration does not necessarily experience comparable emergence in the following year, and we provide the first density estimate for a 4-yr early emergence of 17-yr cicadas (1.28/m2, within the range of published estimates for on-schedule emergences). We also document a 4-yr early 13-yr emergence--cicadas apparently emerging in 9 yr. Multimodal life-cycle patterns spanning -4 to +4 yr are evident in both 13- and 17-yr cicadas. [ABSTRACT FROM AUTHOR]

Periodical cicadas, known for strict life-cycle lengths of 13 or 17 yr, actually exhibit developmental plasticity in cycle length. This variation tends to occur in 1- and 4-yr increments for both life-cycle types, with the largest events involving 4-yr accelerations of the 17-yr species. The pattern has stimulated hypotheses to explain brood formation and life-cycle evolution, but most of the evidence is anecdotal. We present the first quantitative evidence confirming that a site with a 4-yr acceleration does not necessarily experience comparable emergence in the following year, and we provide the first density estimate for a 4-yr early emergence of 17-yr cicadas (1.28/m2, within the range of published estimates for on-schedule emergences). We also document a 4-yr early 13-yr emergence-cicadas apparently emerging in 9 yr. Multimodal life-cycle patterns spanning −4 to +4 yr are evident in both 13- and 17-yr cicadas. [ABSTRACT FROM AUTHOR]

The article presents a study on the response of Magicicada cassini to a model avian predator. The researchers performed the study on a rural area that is 1.2 kilometers west of Towanda in Butler County, Kansas, in which they positioned a stuffed crow or Corvus brachyrhynchos in a perch posture with folded wings above and in front of a cicada. They found that body temperature affected the response of male and female periodical cicadas to an approaching crow model. They also mentioned that the effect of body temperature on the decision process for escaping in cicadas has also been reported for other exothermic animals.