Chapter 1: Fastest Flyer

J.H. Byrd

Department of Entomology & Nematology

University of Florida, Gainesville, FL 32611-0620

May 31, 1994

One of the more controversial aspects of insect flight centers around which species can fly fastest. Published literature indicates that Austrophlebia costalis (Odonata: Aeshnidae) has the fastest flight speed of 98 km/h (Tillyard 1917). However, an unpublished interpolation of male Hybomitra hinei wrighti (Diptera: Tabanidae) flight during female pursuit reveals a record speed of 145 km/h (Butler 1994).

Most flight research has considered hovering, swarming, or tethered flight. Relatively little is known about the maximum velocity which insects can attain. This paper reviews research on insect flight speeds and identifies the insect that currently holds the record of fastest flyer.

Methods

The history of insect flight research was compiled by referring to general entomology textbooks published from the early 1950's through the early 1970's. Surprisingly, references to primary literature in these works were in error or completely absent. However, it was possible to trace some references to their original source. The most useful resource was personal communications with Dr. J.F. Butler, who has done research on insect flight. He provided information that was not available elsewhere.

Results

Very little reliable information has been published on insect flight speed. The first well documented report on insect flight was by Tillyard (1917) who, using a stopwatch, timed the flight of Austrophlebia costalis (Odonata: Aeshnidae) along a downhill slope at 98 km/h. Subsequently, Hocking (1953) calculated that the maximum speed of A. costalis on a level surface was only 57.9 km/h, but noted that with downhill flight Tillyard's figures could be correct.

Demoll (1918) reported that the swiftest flier was a Hawkmoth (Lepidoptera: Sphingidae) with a flight speed of 53.6 km/h. Unfortunately, these measurements were obtained by timing the insects with a stopwatch as they crossed a room towards a window. Due to the artificial environment and failure to indicate maximum error, his calculations are open to debate.

According to Hocking (1953), a seemingly accurate list of insect flight speeds was published by A. Magnan (1934), who timed the insects with a chronometer aided with cinematography as they flew across a grid. Magnan also reported the swiftest flyer to be a Hawkmoth (Lepidoptera: Sphingidae) at 53 km/h. Yet Magnan stressed that this list was not of maximum flight speeds. As a result, Tillyard's record stood until a claim was made by Charles Townsend (1927) who alleged that the males of Cephenemyia pratti (Diptera: Oestridae) were observed as "only a blur" flying at 1317 km/h. Incredibly, authors of general entomology texts took this claim seriously even though no instruments were used in measuring its speed (Frost 1942).

The 1932 Nobel Prize winner Irving Langmuir refuted the speed of C. pratti by calculating the air pressure generated against the front of the insect to be almost two atmospheres, sufficient to crush the insects head. Langmuir's own investigations using visual observations of a model revealed that C. pratti should become a "blur" at 40 km/h. It is noteworthy that this value may be underestimated because he used a 10 mm clay replica instead of an actual 15 mm Cephenemyia pratti (Langmuir 1938).

However, recent research by Dr. J.F. Butler bests previous claims. His unpublished interpolation of slow-motion cinematography research on a pursuit maneuver used by male Hybomitra hinei wrighti (Diptera: Tabanidae) (Wilkerson & Butler 1984) indicates a flight speed at the beginning of female pursuit to be at least 145 km/h (Butler 1994).

Discussion

Much of the early research must be questioned because of the crude methods used to obtain it. May (1991) reports that discrepancies can occur when photographic equipment is used in the estimation of velocity. These discrepancies are due to variations in the number of frames exposed per second, miscalculation of the relative size of the insect in the field of view, and unaccounted changes in the insect flight plane.

The use of sound recordings made as the insect passes two points of known distance is by far the most accurate measure of insect flight speed (May 1991, Butler 1994). While sound wave analysis may be the most accurate method available to estimate insect flight speed, I found no research that used this type of analysis. Instead, high-speed filming, with lesser accuracy, was chosen.

Until many candidates are measured by accurate means, we are unlikely to know what insect is truly the fastest flier. The present record holder may be the male of Hybomitra hinei wrighti at 145 km/h, but published literature supports Tillyard's 1917 calculation of A. costalis flight at 98 km/h, which Hocking (1953) stated could be correct.

Acknowledgements

I express my appreciation to Dr. Tom Walker for helpful reviews of this manuscript, and to Dr. J.F. Butler for explanation of movie camera calibration.

References Cited

Butler, J.F. 1994. Personal communication. Department of Entomology, University of Florida. Gainesville, FL.

Demoll, R. 1918. Der Flug der Insekten und der Vogel. G. Fischer, Jena. (Not seen, cited as to Langmuir 1938).

Frost, S.W. 1942. General entomology. McGraw-Hill, New York.

Hocking, Brian. 1953. The intrinsic range and speed of flight of insects. Trans. Roy. Entomol. Soc. London. 104: 225-345.

Langmuir, J. 1938. The speed of the deer fly. Science. 87: 233-242.

Magnan, A. 1934. Le Vol des Insectes. Paris. (Not seen, cited as to Hocking).

May, M.L. 1991. Dragonfly flight: power requirements at high speed and acceleration. J. Exp. Biol. 158: 325-342.

Tillyard, R.J. 1917. The biology of dragonflies. Cambridge, University Press.

Townsend, C. 1927. On the Cephenemyia flight mechanism and the daylight-day circuit of the Earth by flight. J. New York Entomol. Soc. 35: 245-252.

flight mechanism and the daylight-day circuit of the Earth by flight. J. New York Entomol. Soc. 35: 245-252. Wilkerson, R.C. & J.F. Butler. 1984. The Immelmann Turn, a pursuit maneuver used by hovering male Hybomitra hinei wrighti. Ann. Entomol. Soc. Am. 77: 293-295.

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© Copyright 1994 J.H. Byrd. This chapter may be freely reproduced and distributed for noncommercial purposes. For more information on copyright, see Copyright & Permitted Uses.