File and scraper: katydid signals

Conocephalus fasciatius singing from a spruce tree in a boreal sphagnum bog ~150 km northwest of Thunder Bay, Canada


This is a sort of 'web-book', a personal web memoir under public construction, built around katydid sounds. I like insects and I have studied them since I was a boy in the 1940s; I collected grasshoppers in glass jars confusing crop-content regurgitations with tobacco juice. My favourite quote about liking insects comes from 'Through the looking-glass and what Alice found there' by Lewis Carroll.

"...the Gnat (for that was the insect she had been talking to) was balancing itself on a twig just over her head, and fanning her with its wings.

It certainly was a very large Gnat: "about the size of a chicken," Alice thought. Still, she couldn't feel nervous with it, after they had been talking together so long.

"—then you don't like all insects?" the Gnat went on, as quietly as if nothing had happened.

"I like them when they can talk," Alice said. "None of them ever talk, where I come from."

"What sort of insects do you rejoice in, where you come from? the Gnat inquired. "I don't rejoice in insects at all," Alice explained...

Scanning electron micrograph of a katydid scraper.

As an entomologist of course I do rejoice in insects. And I agree whole-heartedly with the Gnat's premise that all insects inevitably invite celebration; its just a question of choosing which ones you like best. (Not an entirely easy argument when one thinks of blackflies and mosquitoes.) I especially like insects that talk to each other, which is where the 'file and scraper'come in. Tettigoniidae, katydids, mostly make their sounds by rubbing forewings together. A scraper on one wing slides along a row of teeth called a file on a vein of the other wing and this sends wing cell membranes into oscillation, radiating sound – calling to a attract a mate or repel a rival.

File on the left forewing's underside engaged by the scraper on the right wing.

This webbook is to be about those katydid species that have been special to me. Sound, form and doings of insects (acoustics, morphology, behaviour) whose lives have occupied me as a scientist. I hope to set down and explain the scientific part clearly. But I also want to build in some of the personal things that never make it past the editors of scientific journals.

As my own editor working in public, there is good potential for embarrassment. So I will be glad to get intelligence about errors and I am open to suggestion. Unlike a real ink-fixed book, I suppose this site could change its morphology indefinitely, depending on the longevity of the author.

'A swale in upper New York State in the early sixties, habitat for Conocephalus.

I trained as an entomologist at the Ontario Agricultural College (1962) and Cornell University (1967). In 1963 a tettigoniid called Conocephalus fasciatus became my first subject, in an old sunny and weedy field in upper New York State, green on green hard to find, making an ultrasonic call I could not hear. This species sings all across North America. I found it in winter in New Orleans in the old French market where I gave my first scientific paper. I came to map its singing perches in the boreal bogs of Canada's northwest. I think C. fasciatus has to be first.

Glenn Morris, Professor of Zoology

University of Toronto Mississauga.