Cassini periodical cicadas

The Cassini periodical cicadas are a pair of closely related species of periodical cicadas: Magicicada cassini [a] (Fisher, 1852), having a 17-year life cycle, and Magicicada tredecassini (Alexander and Moore, 1962), a nearly identical species with a 13-year life cycle.

Courting behavior of Cassini cicadas is unusual because large groups of males may sing and fly together in synchrony.

The three different types have unique species song-types; they also tend to sing at different times of day, with cassini choruses most likely in mid- to late afternoon, later than decim or decula varieties.

[7] according to Alexander and Moore (1958):[8]Almost every singing male in a woods containing tens of thousands of singers achieves synchrony with all the others, and the result gives the impression of a gigantic game of musical chairs.

A treeful of these insects singing in synchrony is motionless when observed during the great burst of sound caused by insects buzzing together, and then becomes a frenzy of activity between buzzes with nearly every individual changing perches.The "congregational" singing of males (so-called because it inspires both males and females to congregate) requires this synchrony in cassini-types for its success.