Quantifying accelerated emergence of the 17-year periodical cicada (Magicicada cassini) in eastern Kansas

The emergence of periodical cicadas represents a unique and important flux of nutrients from belowground to aboveground habitats.  A small number of individuals within local populations have been shown to emerge four years prior to the major event that occurs every 17 years.  Recent evidence suggests that accelerated emergence is becoming more common, perhaps related to increasing temperatures.  We quantified the emergence of Magicicada cassini in the Flint Hills of Kansas in 2011, which was four years prior to the next anticipated mass emergence.  We were able to compare population densities as well as characteristics of individual cicadas that emerged in 2011 with published estimates from the same site during the last mass emergence in 1998.  Emergence densities were estimated by counting emergence holes using 0.10m2 quadrat frames.  We took ~7,000 frame counts throughout the 100 ha riparian forest of King's Creek at Konza Prairie Biological Station, and we estimated an average of 0.61 insects per square meter.  We also estimated that 610,992 individuals emerged across the entire area, which was 3.1% of the last estimated mass emergence in 1998 (19.6 million individuals).  Interestingly, we also found emergence holes in several sections of forest in which no cicadas emerged in 1998, suggesting a change in distribution.  As this species offers a large flux in nutrients from below to aboveground habitats, a change in life history could have substantial food web implications.  Additionally, the relatively long life cycle of this insect makes it useful as a possible indicator of the effects of warming in temperate areas.