21 s of calling song, male from Dyer County, Tenn., 24.4°C. Dominant frequency 4.7 kHz (WTL489-28). Click on sound bar to hear entire recording.
This sound spectrogram is a 2 s excerpt of the 21 s audio file accessible above. The excerpt begins at 15 s. Click on sound bar to hear graphed song.
11 s of courtship song, male from Worcester County, Mass., 23°C. Dominant frequency -- kHz. Recording by K. N. Prestwich, used by permission. Click on sound bar to hear entire recording.
This sound spectrogram is a 2 s excerpt of the 11 s audio file accessible immediately above. The excerpt begins at 3.5 s. Click on sound bar to hear graphed song.
The soft, nearly continuous, shuffling sounds have a dominant frequency similar to the calling song (4.7 kHz) as do the two-pulse chirps with strong harmonics that are the loudest sounds. In contrast, the brief (10 ms), periodic ticks have their strongest frequencies at about 12 kHz. When courting a female, some males omit the two-pulse chirps in the terminal phase of a successful courtship; others do not.
G. pennsylvanicus and G. veletis cannot be reliably distinguished by either song or external morphology (although in some localities the ovipositors of G. pennsylvanicus average substantially longer than those of G. veletis). However, G. veletis overwinters as mid-to-late instar juveniles, whereas G. pennsylvanicus overwinters in the egg stage. Both species have only one generation per year. Consequently, G. pennsylvanicus adults are most abundant in fall and G. veletis adults are most abundant in spring. In all localities where the species have been studied, a few adults of the two species occur together in midsummer.