In The Song of Insects by George W. Pierce, 1948, a study is reported
in which
the author measured the number of chirps per second produced by a striped
ground cricket at various temperatures.  Crickets are cold-blooded, so it 
might be expected that temperature would affect their behavior, including
chirping.

The variables are:

chirps -- number of chirps per second
temp   -- ground temperature in degrees Fahrenheit