Torkel Weis-Fogh (25 March 1922 – 13 November 1975) was a Danish

zoologist Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the animal kingdom, including the structure, embryology, evolution, classification, habits, and d ...

and

Professor Professor (commonly abbreviated as Prof.) is an academic rank at universities and other post-secondary education and research institutions in most countries. Literally, ''professor'' derives from Latin as a "person who professes". Professo ...

at the

University of Cambridge , mottoeng = Literal: From here, light and sacred draughts. Non literal: From this place, we gain enlightenment and precious knowledge. , established = , other_name = The Chancellor, Masters and Schola ...

and the

University of Copenhagen The University of Copenhagen ( da, Københavns Universitet, KU) is a prestigious public university, public research university in Copenhagen, Copenhagen, Denmark. Founded in 1479, the University of Copenhagen is the second-oldest university in ...

. He is best known for his contributions to the understanding of

insect flight Insects are the only group of invertebrates that have evolved wings and flight. Insects first flew in the Carboniferous, some 350 to 400 million years ago, making them the first animals to evolve flight. Wings may have evolved from appenda ...

, especially the

clap and fling Insects are the only group of invertebrates that have evolved wings and flight. Insects first flew in the Carboniferous, some 350 to 400 million years ago, making them the first animals to evolve flight. Wings may have evolved from appendag ...

mechanism used by very small insects. James Lighthill named this "the Weis-Fogh mechanism of lift generation".

Education

Weis-Fogh was born in

Aarhus Aarhus (, , ; officially spelled Århus from 1948 until 1 January 2011) is the second-largest city in Denmark and the seat of Aarhus Municipality. It is located on the eastern shore of Jutland in the Kattegat sea and approximately northwe ...

and educated at

Research and career

Weis-Fogh was research assistant to the Danish Nobel Prize–winning physiologist

August Krogh Schack August Steenberg Krogh (15 November 1874 – 13 September 1949) was a Danish professor at the department of zoophysiology at the University of Copenhagen from 1916 to 1945. He contributed a number of fundamental discoveries within several ...

, where he studied the flight mechanism of the

desert locust The desert locust (''Schistocerca gregaria'') is a species of locust, a periodically swarming, short-horned grasshopper in the family Acrididae. They are found primarily in the deserts and dry areas of northern and eastern Africa, Arabia, and sou ...

. He pioneered studies of

with Krogh in a classic paper of 1951. He then spent a year at the Copenhagen Institute of

Neurophysiology Neurophysiology is a branch of physiology and neuroscience that studies nervous system function rather than nervous system architecture. This area aids in the diagnosis and monitoring of neurological diseases. Historically, it has been dominated ...

. Weis-Fogh then went to the

in England for four years, where he discovered a

rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Thailand, Malaysia, and ...

y protein,

resilin Resilin is an elastomeric protein found in many insects and other arthropods. It provides soft rubber-elasticity to mechanically active organs and tissue; for example, it enables insects of many species to jump or pivot their wings efficiently. ...

, in insect cuticle. He continued working on insect flight. He returned to Copenhagen as Professor of Zoophysiology, but went back to Cambridge in 1966 to become Professor of Zoology there, continuing to investigate mechanisms of cell

motility Motility is the ability of an organism to move independently, using metabolic energy. Definitions Motility, the ability of an organism to move independently, using metabolic energy, can be contrasted with sessility, the state of organisms th ...

and of flight.

Insect flight

In 1973 Weis-Fogh devised a mathematical model explaining how extremely small insects such as

thrips Thrips (order Thysanoptera) are minute (mostly long or less), slender insects with fringed wings and unique asymmetrical mouthparts. Different thrips species feed mostly on plants by puncturing and sucking up the contents, although a few are ...

and

chalcid wasp Chalcid wasps (, , for their metallic colour) are insects within the superfamily Chalcidoidea, part of the order Hymenoptera. The superfamily contains some 22,500 known species, and an estimated total diversity of more than 500,000 species, me ...

s such as ''

Encarsia formosa ''Encarsia formosa'' is a species of chalcidoid wasp and a well known parasitoid of greenhouse whitefly, one of the first to be used commercially for biological pest control, from the 1920s. They can use at least 15 species of whitefly as a hos ...

'' could fly using

clap-and-fling Insects are the only group of invertebrates that have evolved wings and flight. Insects first flew in the Carboniferous, some 350 to 400 million years ago, making them the first animals to evolve flight. Wings may have evolved from appenda ...

, where conventional

steady state In systems theory, a system or a process is in a steady state if the variables (called state variables) which define the behavior of the system or the process are unchanging in time. In continuous time, this means that for those properties ''p' ...

aerodynamics Aerodynamics, from grc, ἀήρ ''aero'' (air) + grc, δυναμική (dynamics), is the study of the motion of air, particularly when affected by a solid object, such as an airplane wing. It involves topics covered in the field of fluid dy ...

did not apply. These insects gain lift by creating vortices near their wings, at the price of the wear and tear from repeated clapping. The British mathematician Sir James Lighthill named this the ''Weis-Fogh mechanism of lift generation''. Weis-Fogh's 1973 paper ''Quick Estimates of Flight Fitness in Hovering Animals, Including Novel Mechanisms for Lift Production'' has been cited over 1000 times.

Awards and honours

The Hanne and Torkel Weis-Fogh fund is named in his honour.

References

{{DEFAULTSORT:Weis-Fogh, Torkel 1922 births 1975 deaths 20th-century Danish zoologists Danish entomologists Professors of Zoology (Cambridge, 1866) Danish physiologists University of Copenhagen faculty University of Copenhagen alumni Danish expatriates in the United Kingdom