About

This is a website fashioned by a retired entomologist recalling his research on insects. My main interest was to understand how and why a group of singing insects -- katydids (Tettigoniidae) -- evolved to produce sounds by rubbing their forewings together. Said like that the subject seems quite narrow. How many ways can there be to rub wings and radiate sound? Fact is, among these tettigoniids there are many and diverse ways of rubbing and radiating. Largely without exception no two species sing the same time domain pattern and their spectra in the frequency domain are likewise disparately diagnostic. Of special interest to me was always the occurrence in insect songs of very short-wavelength sound frequencies -- ultrasonic frequencies -- beyond 20,000 Hz, the nominal limit of human hearing.

I taught behavioural ecology and (still) a kind of biomechanical physiology addressing ' forces and form'. Behaviour and biomechanics are linked. The behaviour of structures e.g. their actions during locomotion, feeding, calling etc. can offer insight into the adaptiveness of their form. A way to approach understanding of a structure's function, be it leaf or trunk, wing or fin, is to observe it in operation, if possible in comparison to other organisms subject to similar selection, then imagine it otherwise --  imagine it as it isn't: how would the katydid's forewing sound generator work if made of a different material, if moved at a different speed, if it were more or less elastic, etc. The aphorism above is a website motto: imagine as it isn't -- in order to know better how and why it is.

In 2009 the library at my university organized an exhibition of Books that Inspire Faculty. My book choice was: The Songs of Insects: with related material on the production, propagation, detection and measurement of sonic and supersonic vibrations, published in 1948. The author, George W. Pierce, was a Harvard physicist, known for achievements in radio communication. For a decade (from 1936) he studied calls of insects at his summer residence in Franklin New Hampshire using equipment for recording he made himself that was sensitive to ultrasonic sound.  Pierce's own words sum up his major contribution: "The matter of audible and superaudible frequencies of the air-borne sound spectrum merits close consideration because these researches show that frequencies extending from the audible to the superaudible exist in the sounds emitted by insects. With some classes of insects I have found that the significant part of their sounds is of a frequency so high as to be entirely inaudible to the human ear...".

In 1963 I was a naive graduate student at Cornell University, hunting up an arthropod as a research topic. I found a delicate green meadow katydid, Conocephalus fasciatus, singing in the sun, perched in the vegetation of a weedy 'old field'. His song detected by hetrodyne, was mostly ultrasonic, a broad band of frequencies between 28 and 50 kHz, peaking near 40 kHz -- highly ultrasonic. From the field I withdrew to Cornell libraries and there discovered Songs of Insects by Professor Pierce. He thus set me on a path of researching katydid sound signals for the information content of their songs. In the Andes in the nineteen eighties I found a species (Myopophyllum) singing above 80 kHz. In the late nineties yet another (Supersonus) in coastal rainforests of Colombia with a spectral peak above 130 kHz. Though I never met the author of 'The Songs of Insects' his book on 'supersonics' led to a lifetime study of insect acoustic communication. One species of Supersonus is now named S. piercei in acknowledgement of his pioneering work.

Glenn Karl Morris,

Prof. emeritus of  Zoology,

University of Toronto Mississauga