Oecanthus nigricornis
Black-horned tree crickets are indistinguishable from Forbes’ tree crickets in appearance. Only the speed of the song is different.
In this video, we can hear the loud song of a Forbes’ tree cricket in the beginning. You can hear when the male Black-horned tree cricket (inside the sleeve) begins to sing.
The spectrogram below shows the moment the male Black-horned tree cricket in the above video begins to sing. Note the sudden appearance of tall reddish spikes above the row of yellow indicators.
In the 1 second spectrogram below, the Forbes’ tree cricket’s song pulses are in yellow, and the Black-horned’s song pulses are the tall mostly reddish spikes. If you count the number of yellow colored indicators in the middle of the strip, you will find 45 pulses. The reddish spikes above the row of yellow indicators total 37.
Using the graph below, knowing the temperature in that spot was 65F, you can plot 37and 45 to see that the pulse counts align with Black-horned and Forbes’ respectively. In cooler temperatures, the rate is more difficult to separate by human hearing. In hot temperatures, however, notice there would be a difference of 20 pulses per second at 90F.
This graph, along with others for US species, can be accessed on the Singing Insects of North America website. This Forbes’ vs Black-horned graph is here: s576lw63.pdf (orthsoc.org)
These tree crickets below have a great deal of black, but many Black-horned tree crickets are mostly green.
