Edward L. Kessel (1904–1997): The Master of the Smoke Flies
Edward Luther Kessel was a distinguished American entomologist, educator, and taxonomist whose career spanned the greater part of the 20th century. While he was a polymath in the biological sciences, he is most revered in the scientific community as the world’s foremost authority on the Platypezidae (flat-footed flies) and for his pioneering observations on the "smoke flies" of the genus Microsania.
1. Biography: A Life in the Laboratory and the Field
Early Life and Education
Edward L. Kessel was born on April 27, 1904, in Oakes, North Dakota. He displayed an early affinity for the natural world, which led him to the University of California, Berkeley. At Berkeley, he completed his undergraduate studies (B.S., 1925) and continued through his graduate work, earning an M.S. in 1928 and a Ph.D. in 1936. His doctoral research focused on the complex embryology of insects, a foundation that would inform his meticulous taxonomic work later in life.
Academic Career
Kessel’s professional life was defined by his long-standing tenure at the University of San Francisco (USF). Joining the faculty in the late 1920s, he served as a Professor of Biology for over 40 years. He was instrumental in building the university’s science department, serving as the chairman of the Biology Department and mentoring generations of pre-medical and graduate students.
Parallel to his teaching, Kessel held a deep association with the California Academy of Sciences (CAS) in Golden Gate Park. He served as a Research Associate and later as a Curator in the Department of Entomology, where he deposited the vast majority of his scientific collections.
2. Major Contributions: Taxonomy and Pyrophily
The Authority on Platypezidae
Kessel’s primary scientific contribution was the systematic revision of the family Platypezidae. These small, inconspicuous flies are known for their "flat feet" (enlarged hind tarsi) and their unique life cycles, which are often tied to fungi. Kessel described dozens of new species and several new genera, effectively mapping a family of insects that had been largely ignored by previous dipterists.
Discovery of "Smoke Flies" (Pyrophily)
Perhaps Kessel’s most intriguing contribution was his study of pyrophilous behavior in insects—specifically in the genus Microsania. He discovered that these flies are attracted to the smoke of wood fires. Kessel spent years investigating why these insects swarm in smoke; he determined that the smoke acts as a "swarm marker," providing a chemical or visual cue for mating aggregations. His field methods were legendary; he was known to carry a small portable stove or follow forest fires to collect thousands of specimens that were otherwise invisible to science.
The Embryology of Siphonaptera
Early in his career, Kessel published a definitive study on the embryology of fleas. This work was critical in understanding the developmental biology of parasitic insects and remains a cited reference for insect morphologists.
3. Notable Publications
Kessel was a prolific writer, contributing over 100 papers to scientific literature. His most influential works include:
- The Embryology of Fleas (1939): Published in Smithsonian Miscellaneous Collections, this monograph provided an exhaustive look at the internal development of Ctenocephalides felis (the cat flea).
- The Smoke Flies of the Genus Microsania (1947): A seminal paper detailing the bizarre attraction of these flies to smoke.
- The Platypezidae of the Ethiopian Region (1965): A massive taxonomic undertaking that expanded the known diversity of flat-footed flies in Africa.
- Editor of The Wasmann Journal of Biology: For over 30 years, Kessel served as the editor-in-chief of this journal. Under his leadership, it became a respected outlet for West Coast biological research.
4. Awards and Recognition
While Kessel did not seek the limelight, his peers recognized him as a titan of entomology:
- President of the Pacific Coast Entomological Society (1947): A testament to his leadership among Western American scientists.
- Fellow of the California Academy of Sciences: An honor reserved for scientists who have made significant contributions to the natural sciences.
- Professor Emeritus, USF: Upon his retirement, he was honored for his decades of service to the university and his role in establishing USF as a center for biological study.
5. Impact and Legacy
The Kessel Collection
Kessel’s legacy is physically preserved in the Edward L. Kessel Collection at the California Academy of Sciences. It contains over 60,000 specimens, including numerous "type specimens" (the original specimens used to describe a new species). This collection remains a vital resource for entomologists worldwide.
Educational Impact
Kessel was known as a "teacher’s teacher." His rigorous standards at USF helped the university gain a reputation for producing high-quality medical students and researchers. He emphasized the importance of "whole-organism" biology in an era that was increasingly shifting toward molecular biology.
6. Collaborations and Family
Kessel’s work was often a family affair. He frequently collaborated with his wife, Berta B. Kessel, who assisted in field expeditions and the preparation of manuscripts.
His daughter, Brina Kessel (1925–2016), followed in his footsteps to become a world-renowned ornithologist and a pioneer for women in science at the University of Alaska, Fairbanks. The Kessel family’s collective impact on American natural history is substantial.
In the lab, Kessel worked closely with other giants of entomology at the California Academy of Sciences, including Edward S. Ross (the world expert on Embioptera) and Paul H. Arnaud Jr., who eventually succeeded him in his work on Diptera.
7. Lesser-Known Facts
- Faith and Science: Kessel was a devout Christian and saw no conflict between his faith and his scientific rigor. He contributed a chapter to the 1958 book The Evidence of God in an Expanding Universe, where he argued that the complexity of biological systems (like the embryology of a flea) pointed toward an intelligent designer.
- The "Fire Chaser": During the summer months, Kessel was known to drive toward forest fires in California and Oregon. While others were fleeing, he would park his vehicle and stand in the smoke with a net, capturing Microsania flies that swarmed around the heat.
- Longevity in Research: Kessel remained scientifically active well into his 80s. Even after his official retirement, he could be found in his office at the California Academy of Sciences, hunched over a microscope, meticulously labeling flies that were no larger than a grain of pepper.