David Pimentel (May 24, 1925 – December 8, 2019) was an American entomologist. He was a professor of Insect Ecology & Agricultural Sciences in the Department of Entomology and Section of Ecology and Systematics at Cornell University. He made contributions in ecology, entomology, agriculture, biotechnology, conservation, and environmental policy. He was recognized as an international authority on many important interactions between humans and the environment. He published over 700 scientific items, of which 37 are books, and served on many national and government committees, including the National Academy of Sciences, the President's Science Advisory Council, the Office of Technology Assessment of the U.S. Congress, the U.S. State Department, and the Departments of Agriculture, Energy, and Health, Education and Welfare. Pimentel served on committees for many national and government organizations, including the Secretary's Commission On Pesticides And Their Relationship To Environmental Health (United States Department of Health, Education, and Welfare) which issued a report in 1969 that recommended the banning of DDT and led to the creation of the EPA.

Pimentel was an agronomist and entomologist, but he had a broad ecological perspective on agronomy, which usually is focused narrowly on yields and production. In the early 1970s he pointed out the energy intensiveness of modern agriculture.Pimentel, D., L.E. Hurd, A.C. Bellotti, M.J. Forster, I.N. Oka, O.D. Sholes, and R.J. Whitman. (1973). Food production and the energy crisis. Science 182: 443-449. He followed that with several important papers on soil erosion.Pimentel, D., J. Allen, A. Beers, L. Guinand, R. Linder, P. McLaughlin, B. Meer, D. Musonda, D. Perdue, S. Poisson, S. Siebert, K. Stoner, R. Salazar, and A. Hawkins. (1987). World agriculture and soil erosion. Bioscience 37:277-283.Pimentel, D., C. Harvey, P. Resosudarmo, K. Sinclair, D. Kurtz, M. McNair, S. Crist, L. Spritz, L. Fitton, R. Saffouri, and R. Blair. (1995). Environmental and Economic Costs of Soil Erosion and Conservation Benefits. Science 267: 1117-1123. In 1999 Pimentel published estimates detailing the economic losses of invasive species. He estimated an annual economic loss of $123 billion. In most of his studies he attempted to generate quantitative estimates, even of quite difficult and large scale issues.

Pimentel calculated that the policy of growing maize to produce the ethanol, as well as other biofuels, cost more energy to maintain than it actually produced. These conclusions were met with hostility from some quarters.Is Ethanol Energy-Efficient? http://journeytoforever.org/ethanol_energy.html

Early life and education Pimentel was born on May 24, 1925, in Fresno, California and moved with his family to a farm in North Middleboro, Massachusetts.Whitecraft, Michele, Going Against "Procedures": A Profile of Dave Pimentel. Manuscript. Before finishing high school, he volunteered for the Army Air Force and was trained as a pilot. He received his B.S. degree from UMASS Amherst in 1948. He received his PhD in entomology from Cornell University in 1951, also having a graduate fellowship at Oxford University that same year. After obtaining his graduate degree, he was recalled to military service, serving instead for 4 years with the US Public Health Service in Puerto Rico. He returned to Cornell in 1955, where he remained for the rest of his life, becoming the Chairman of the Entomology Department and holding a joint appointment with Ecology and Systematics.

Scientific career Pimentel began his career at Cornell studying pest control and DDT in house flies.Pimentel, D. and J.E. Dewey. (1950). Laboratory tests with house flies and house fly larvae resistant to DDT. Journal of Economic Entomology 43:105.Pimentel, D., H.H. Schwardt, and J.E. Dewey. (1954). The inheritance of DDT-resistance in the house fly. Annals Entomological Society of America 47:208-213. During his time in Puerto Rico, he studied the introduced mongoose.Pimentel, D. (1955). Biology of the Indian mongoose in Puerto Rico. Journal of Mammalogy 36: 62-68.Pimentel, D. (1955). The control of the mongoose in Puerto Rico. American Journal of Tropical Medicine and Hygiene 4:147-151. Early work, such as on herbicides, is still cited today. At the intersection of agriculture and food security, Pimentel was concerned about the effects of chemical inputs and modern farming techniques on production in agriculture. Pimentel also warned that human overpopulation is a function of food availability.Hopfenberg, Russell and Pimentel, David, "Human Population Numbers as a Function of Food Supply", Environment, Development and Sustainability, vol. 3, no. 1, March 2001, pp. 1–15 In his later years, he took an interest in the environmental effects of global warming.

In 1961, Pimentel published on several important topics in ecology, including diversity-stability,Pimentel, D. (1961). Species diversity and insect population outbreaks. Annals Entomological Society of America 54:76-86. spatial patterns,Pimentel, D. (1961). The influence of plant spatial patterns on insect populations. Annals Entomological Society of America 54:61-69. and community structure.Pimentel, D. (1961). Competition and the species-per-genus structure of communities. Annals Entomological Society of America 54:323-333. It was also the year that he presented his model integrating population dynamics and genetics that he called genetic feed-back.Pimentel, D. (1961). Animal population regulation by the genetic feed-back mechanism. The American Naturalist 95:65-79. He later presented data for it.Pimentel, D. (1968). Population regulation and genetic feedback. Science 159:1432-1437. It was one of the earliest attempts at mathematically combining genetics with population dynamics.Drtischilo, W. (2019). Earth Days Reprised. Available from Amazon.com. Half a century later, it was cited as a paper that presaged the currently hot field of eco-evolutionary dynamics.Schoener, T. W. (2011). The Newest Synthesis: Understanding the Interplay of Evolutionary and Ecological Dynamics. Science 331:426-429.

Pimentel's forays into the environmental field came out of his experiences on various government panels and study groups, especially his year as an ecological consultant to the Office of Science and Technology. His study of the energy inputs into the productions of cornPimentel, D., et al. (1973). was published during the energy crisis of 1973 and became his most cited paper ever. It was followed up by a study of the energy inputs to beef production.Pimentel, D., W. Dritschilo, J. Krummel, and J. Kutzman. (1975). Energy and land constraints in food-protein production. Science 190:754-761. By then, he was on his way to becoming a voice that was listened to on a variety of environmental issues through the numerous studies that he led and published, the results of which always could, and were, inspected and revised.

He was not a scientist who shied away from controversy or feared contradicting established views. Early in his career, he took on the biological control establishment by suggesting that native pests could be controlled by introducing new parasites and predators, based on his observations of successful control of pests in new associations and his genetic feedback model.Pimentel, D. (1963). Introducing parasites and predators to control native pests. Canadian Entomologist 95: 785–792. It was not an idea that was readily accepted, however, particularly by California biocontrol experts.Huffaker,C.B., Simmonds, S.J., and J.E. Laing. (1976). "The theoretical and empirical basis of biological control." Pages 41-78 in Huffaker, C.B. (ed.) Biological Control, Plenum Press, NY. 511 pp. They admitted that, "Outstanding biological control successes have sometimes been achieved ... by the use of natural enemies whose hosts belong to different species or genera from the pests they are needed to control,"Wilson, F., and C.B., Huffaker. (1976). Pages 5-6 in Huffaker, C.B., and PS Messenger. (eds.) Theory and practice of biological control. Academic Press, New York. 788 pp. but they then rejected (pp 47–49) Pimentel's work on genetic feedback as an explanatory mechanism involved in biocontrol by insect parasites and predators. Undaunted, Pimentel continued to support and document the use of new associations in biocontrol.Hokkanen, H.M.T., and D. Pimentel. (1989). New Associations in Biological Control: Theory and Practice. Canadian Entomologist 121:829-840. This practice has been called "new association biological control" as opposed to "classical biological control".Van Driesche, R., and M. Hoddle. (2009.) Pages 4-5 in Control of pests and weeds by natural enemies: an introduction to biological control. Blackwell Publishing. Malden Massachusetts. 488 pp.

Pimentel was a pioneer in tabulating the energy cost, fossil fuel in particular, of food production. When his suggestion that "energy was going to be important to agricultural research in the future" was rebuffed as an area of study by a 1968 National Academy of Science Panel on which he served, Pimentel set about to put together the needed data himself by creating a graduate research course to do so using his own students.Dritschilo, W. (2019). Earth Days Reprised. (Pp 389-390.) Coming out during the 1973 energy crisis, the paper on energy inputs to corn production received much attention and helped to launch a number of studies and papers, including many by Pimentel and his colleagues. That paper then putatively initiated the controversy over the net energy and environmental impacts of gasohol crops.Ruttan, V.W. and Pimentel, D. (1975). Food Production and the Energy Crisis: A Comment. Science 187:560-561.Pimentel, D. (1975). Food Production and the Energy Crisis: A Comment. Science 187:561.Chambers, R.S., Herendeen, R.A., Joyce, J.J., and P.S. Penner. (1979). Gasohol: Does It or Doesn't It Produce Positive Net Energy? Science 206:789-795. Pimentel took great solace in having had his work reviewed by "26 top scientists and engineers" who found his methods to be sound.ERAB. (1980). Gasohol: Energy Research Advisory Board. U.S. Dept. Energy, Washington, DC.ERAB. (1981). Biomass energy: Energy Research Advisory Board. U.S. Dept. Energy, Washington, DC. Pimentel claimed criticism such as that raised by Bjørn Lomborg,Lomborg, B. (2001) The Skeptical Environmentalist. Cambridge University Press. was only a disagreement on details, rather than conclusions, stating he was correct anyway despite the fact that the numbers he used in his calculations later turned out to be wrong.Pimentel, D. (2002). Exposition on Scepticism. BioScience 52:295-8.

Biomass fuels