Thomas Eisner: Interpreter extraordinaire of nature’s chemistry May R. Berenbaum1 Department of Entomology, University of Illinois at Urbana–Champaign, Urbana, IL 61801-3795 n March 25, 2011, Thomas being discharged, beetles being spat out, Eisner died after a long and cou- spiders paralyzed by millipede alkaloids, Orageous battle with Parkinson’s fantastic fecal matter being brandished disease. His tremendous legacy by tortoise beetles, and hundreds more, included founding and nurturing the sci- vividly rendering chemical communication entific discipline of chemical ecology. visible to a broad audience, often developing Tom, though, might be the only person in novel photographic techniques to do so. the field to dispute his rights to the title, Cornell provided Tom with not only “Father of Chemical Ecology”—indeed, stellar students but also a superbly skilled in one interview (1), he wryly opined and uniquely like-minded chemist with that such claims cried out for DNA pa- whom to collaborate. In a partnership that ternity tests. began in 1960, Tom published more than Born in Berlin, Germany, on June 25, 130 of his 300+ refereed journal pub- 1929, Tom was the son of the gifted painter lications with Jerrold Meinwald. Together Margarete Eisner and the chemist Hans they determined the structure and function E. Eisner, a student of Nobel Laureate of defensive secretions, aphrodisiacs, Fritz Haber. His parents’ accomplishments glues, pigments, and pheromones, from did little to protect the Jewish family chemical classes ranging from one-carbon from Nazi threats, and the Eisners left hydrogen cyanide from oozing glands of Germany in 1933, traveling to Barcelona, millipedes to the 200-plus carbon macro- Spain, where Hans Eisner found work with cyclic polyamines in the trichomes of a private chemical company. Soon there- squash beetles, among the largest non- after the chaos of the Spanish Civil War protein natural products known. Beyond led them to move again, first to France founding a new discipline linking the and then to Uruguay. Tom spent almost Tom Eisner. physical and biological sciences (long be- a decade in Uruguay, and during this rel- fore such linkages became routine), Tom atively stable period of his life he devel- and Jerry demonstrated the utility of nat- oped his growing interest in natural see their significance in the life of the or- ural history studies to obtain scientific in- history. After he graduated from high ganism. Detecting invisible chemicals by sights, the power of bioassays to ascertain school, the family immigrated to the their morphological signposts was Tom’s ecological functions, and the value of United States in the hope of finding forte; he determined functions for folds, embedding laboratory studies in ecologi- greater educational opportunities for the wrinkles, and projections that systematists cal, behavioral, and environmental con- children. Access proved difficult: Tom was had meticulously described but never in- texts. The two worked together to offer rejected by Cornell University but was vestigated. Elytral flanges of ground bee- one of the nation’s first courses in chem- admitted to Champlain College in Platts- tles defining membership in the subfamily ical ecology, and in 1990 to found the burg, NY. After two years he transferred Paussinae in the family Carabidae, for Cornell Institute for Research in Chemical to Harvard University, where he took example, were shown to function as part of Ecology, the first academic institute dedi- his first course in entomology, sparking the equipment used as launching guides cated to the discipline. They also orga- a lifelong fascination. After receiving a BA to direct and deflect toxic, boiling hot nized two collections of papers in chemical in 1951, he stayed four more years for spray at predators, an application of ecology and published them in PNAS as a PhD, studying insects with Frank Car- technology familiar to aviation scientists as special features in 1995 and 2008 penter and collaborating with fellow the Coanda effect (3). Feathery starbursts (http://www.nap.edu/openbook.php?isbn= graduate student (and lifelong friend) projecting from the abdomens of male 0309052815; http://www.pnas.org/cgi/ Edward O. Wilson. After two years as bella moths and queen butterflies proved collection/chemical_ecology). Beyond a research associate at Harvard, Tom was to be elaborate delivery devices for plant- academe, Tom coined the term and tire- hired as an assistant professor at Cornell. derived aphrodisiacs (4). Color, too, was lessly promoted the concept of “chemical He remained there for his entire career, an important signpost for chemical com- prospecting” as a tangible, economic jus- rising rapidly through the ranks and being munication—many chemically defended tification for biodiversity conservation, a named Jacob Gould Schurman Professor insects signal their toxicity with bright staple principle in chemical ecology (6). In of Chemical Ecology in 1976. For 54 years, colors signifying distastefulness. Tom thus addition to working together, Tom and he kept on the wall of his office the framed worked with some of the Class Insecta’s Jerry played together: both accomplished original Cornell rejection letter he had most colorful members. Cochineal scale, musicians, they performed together on received in 1947. for example, was known as a source of many occasions, with Jerry on flute and Tom’s early work on morphology— brilliant red pigment since Aztec times, Tom at the piano. among his first publications were analyses but Tom was the first to document that the of the proventriculus of ants (2)—antici- bitter-tasting pigment actually deters pated an important dimension of his entire predators (5). With his refined aesthetic Author contributions: M.R.B. wrote the paper. career, notably, his uncanny ability to no- sense and amazing technical skills, he cap- The author declares no conflict of interest. tice distinctive structural features and to tured images of chemicals at work—sprays 1E-mail: [email protected]. 19482–19483 | PNAS | December 6, 2011 | vol. 108 | no. 49 www.pnas.org/cgi/doi/10.1073/pnas.1114761108 Downloaded by guest on September 26, 2021 RETROSPECTIVE From his peripatetic childhood, Tom (7), with greatly magnified defensive hairs gained fluency in French, German, Span- glistening like Christmas ornaments, is ish, and English and an enduring interest worthy of framing and hanging over a in world affairs; visiting appointments fireplace. were spent in The Netherlands, Panama, Finding beauty and chemistry in a cab- Germany, Australia, and Switzerland. He bageworm, to me, epitomizes Tom’s in- also traveled extensively around the satiable curiosity, remarkable intellect, United States, almost entirely by car. On and warm personality. He was a serious one trip as a new assistant professor, he scientist who never lost perspective and found the Archbold Biological Station in never lost his sense of humor. As Parkin- Lake Placid, FL; he became a regular son’s disease robbed him of the ability to visitor, and its dazzling biodiversity in- hold and manipulate small objects (in- spired many of his best-known studies. cluding his beloved insects), he remained Tom’s personal history also gave him The bombardier beetle Stenaptinus insignis aims philosophical; he once told me that he a keen appreciation of how political pol- its hot quinonoid spray by precisely revolving thought the disease might have been the the tip of its abdomen (reproduced from ref. 9). icies can interfere with the conduct of consequence of a half-century of more or science, and throughout his life he was an less constant exposure to oxidizing ar- ardent defender of human rights and sci- thropod defensive secretions—condign sons, my personal favorite among his 400+ entific freedom, serving on the National retribution of a sort for poking, prodding, papers involves a study of one of the most Academy of Sciences Committee on Hu- and often grinding up so many insects over contemptible of insects, if familiarity man Rights and chairing the American Pieris rapae the years. Association for the Advancement of Sci- breeds contempt. , the im- Paternity or no, every chemical ence Subcommittee on Science and Hu- ported European cabbageworm, is argu- ecologist today in a sense owes his or her ably America’s most ubiquitous butterfly— man Rights for 8 years. He actively fl career to the vision and energy of contributed to national debates on the occurring coast to coast and ying from Tom Eisner. Chemical ecologists are biological effects of nuclear war, pop- early spring to late fall. As a caterpillar, it countable—acheckofthemembership ulation control, and global climate change is a noxious pest of cabbage and other cole list of the International Society for and appeared before Congress on multi- crops. In this thoroughly well-studied Chemical Ecology provides at least ple occasions, testifying on biodiversity creature, Tom saw hairs with sticky glob- a rough approximation. What cannot be conservation, endangered species legisla- ules, of unknown function. With Meinwald counted, however, are the thousands of tion, and bioprospecting. and others, Tom found that this Rodney individuals, in biology classes in school I was exceptionally fortunate to have Dangerfield of caterpillars produces a or at home watching the Public Broad- met Tom early in my career, while I was a novel class of linolenic acid-derived natu- casting Service or reading For Love of graduate student at Cornell. Tom was ral products. To my unutterable delight, Insects (8), who have been intrigued and unfailingly an inexhaustible source of these generous scholars named these se- inspired by Tom’s work and who gained useful information on a staggering range of cretions mayolenes in my honor—and the a greater appreciation of the scientific subjects and a relentless fount of encour- image of the lowly cabbageworm that ap- enterprise (and a greater admiration of agement and good cheer. For selfish rea- peared in PNAS accompanying the article the Class Insecta) as a result.