male crickets chirp to attract females, and in some species, their calls can be heard from great distances. however, a certain parasitic fly has taken advantage of this, the female is attracted to a calling male cricket on which it then deposits its developing larvae. elaborate song is especially well-developed among birds, and again sexual selection has driven its evolution. songbirds such as warblers have an extensive repertoire of songs, sometimes with thousands of phrases. the sedge warbler assembles an effectively infinite number of songs by assembling phrases in combination. laboratory experiments by clive catchpole demonstrate that female sedge warblers select males with more varied songs, while field observation indicates that such males attract mates before other males.