Saturday, September 8, 2012

Katy Didn't: The silence of the summer nights

Broad-winged Bush Katydid Scudderia pistillata Brunner, 1878
Summer nights in central Alberta aren't really silent, the coyotes, frogs, owls, and honkers see to that. Anyone who has camped near where a beaver is chewing on a tree knows that the nights can be quite noisy (and a bit worrisome - where will it fall?). But the pulsating throbs of insects singing in the dark that are so dominant in warmer parts of the World are generally absent here. That led me to the false assumption that Alberta lacked the crickets (Gryllidae) and katydids (Tettigoniidae) of the eastern North American nights. Imagine my surprise, when I found I was sharing a pasture with a large Broad-winged Bush Katydid

Sometimes called the 'counting katydid' because the males add a syllable to each successive phrase of its song, I had to be startled by a large katydid springing up from a bush to know they were there. Am I going deaf? Well, possibly. The songs of bush katydids are rather high-pitched and difficult for some people to hear. Also, bush katydids are members of the subfamily Phaneroptinae - also known as False Katydids - and they are more of the clicking than singing variety. The true katydids (confusingly placed in the subfamily Pseudophyllinae, meaning 'false-leaf') in the Eastern nights loudly argue Katy's virture: Ka-ty did! Ka-ty didn't! Ours seem to be quietly counting their scratches in a pitch too high for me.
Slender Meadow Katydid Conocephalus fasciatus (De Geer, 1773)
But wait, there's more! Once I started looking I found our cabin was surrounded by hundreds of small meadow katydids (subfamily Conocephalinae - 'cone heads'). They all seem to belong to one species, the Slender Meadow Katydid Conocephalus fasciatus and although much smaller (about an inch long) than the bush katydids, they should be making some noiseLike other katydids, male meadow katydids sing by rubbing their wings together. Alas, again like bush katydids, it seems our meadow katydids are singing a bit too high for me to hear more than a faint buzz.
Female Katydids listen, Male Katydids sing - the sword-like ovipositor means silent female
Fortunately for my aging, rock-addled ears, there is a wonderful website called Songs of Insects where I can listen to both our species both in their too high-pitched for the Home Bug Gardener or lowered a couple of pitches for the hard of hearing.

For more on the sounds of insects:

Songs of Insects

and for the sounds of nature in general:

The Music of Nature

and while they don't yet seem to have anything on Alberta (alas no beaver gnawing), there is a very nice Manitoba dawn chorus:

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