Emergence of periodical cicadas (Magicicada cassini) from a Kansas riparian forest: Densities, biomass and nitrogen flux

The 1998 emergence of 17-y periodical cicadas (Magicicada cassini) on Konza Prairie Research Natural Area (KPRNA), Kansas, was quantified using emerge nce trap transects and counts of emergence holes. Emergence density, biomas s (emergence production) and associated nitrogen flux were estimated for th e entire 100 ha gallery forest of Kings Creek, the major drainage network o n KPRNA. Emergence commented on 22 May 1998 and lasted for 24 d, with 87% o f the individuals emerging within the first 9 d. Males dominated early duri ng the emergence, and the sex ratio for the entire population was estimated at 54:46 male:female. Average emergence abundance and biomass estimated fr om trap transects located in low areas where cicadas were most abundant wer e 152/m(2) and 34.9 g ash-free dry mass (AFDM)/m(2), respectively. Based oi l emergence hole counts, average density and biomass for the 59 ha of galle ry forest where cicadas emerged were 27.2 individuals/m(2) and 6.3 g AFDM/m (2), and emergence hole densities, >100/m(2) were evident in low areas of t he drainage. Emergence density generally decreased with increasing elevatio n in the catchment. Belowground to aboveground N flux associated with M. ca ssini emergence in high density areas was similar to3 g N/m(2), and the ave rage for the entire emergence area was 0.63 g N/m(2). The total number of i ndividuals that emerged from the Kings Greek riparian forest was estimated at 19.6 million, which represents 4.6 metric tolls AFDM and similar to0.5 m etric tons N. This linear, fragmented, gallery forest of the Flint Hills su pports a high density of M. cassini, and an emergence el ent constitutes a significant belowground to aboveground flux of energy and nutrients. Thus, the periodical cicada may he art exception to the notion that insects gener ally do not represent important resource pools at the ecosystem level.