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Charles L. Judson
In Memoriam

Charles L. Judson

Professor of Entomology, Emeritus

UC Davis
Noted insect physiologist Charles L. Judson, a UC Davis emeritus professor of entomology widely recognized for his work on the feeding and oviposition behavior of mosquitoes, died July 26, 2015, from complications of Alzheimer's disease. He was 88.

A resident of Davis, Judson served as a faculty member of the UC Davis Department of Entomology (now the UC Davis Department of Entomology and Nematology) for 30 years, from 1961 until his retirement in 1991.

"The Department of Entomology and Nematology lost one of its pillars with the passing of Dr. Judson," said Michael Parrella, professor and chair of the department. "Although the department's national and international reputation is based on the work of current faculty, it cannot be denied the prestige of the department can also be attributed to our retired faculty. It sounds clichéd, but we are standing on the shoulders of giants and Dr. Judson was one of these. Dr. Judson continued to be an active member of the department -- coming regularly to our seminars and participating in social events. Up until a few years ago, he helped teach our core course in Insect Physiology. Charles Judson's contributions to the science of entomology and to the department will never be forgotten." 

Born Oct 21, 1926 in Lodi, Calif., Charles grew up on a ranch in Riverside, where he developed and nurtured his passion for the outdoors, nature, science and animals. He enlisted in the U.S. Navy during World War II, serving on the USS Wichita.

He received his bachelor of science degree in zoology from UC Santa Barbara in 1950, and his doctorate in entomology from UC Berkeley in 1954. He and his wife, Marilyn, and family moved to Davis in 1958 when he accepted a position with the California Department of Public Health. He joined the UC Davis faculty in 1961 as an insect physiologist professor. He was a 35-year member of the Entomological Society of America.

The couple raised three children: Todd, now a pilot who lives in Sacramento; Bruce, an engineer living in San Luis Obispo, and Jan, a nurse practitioner at the UC Davis Student Health Center. They provided them with four grandchildren, Nik and Karli, children of Jan and Larry; Andie, daughter of Bruce and Joan; and Leah, daughter of Todd and Kay. They shared his love of the outdoors and his sense of humor.

“Our family quickly learned not to be afraid of insects, but to respect them in our environment,” recalled Jan. “We don't squish most bugs, but put them outside.”

“Charles enjoyed his work as a researcher and student advisor and often would invite students to his home, maintaining lifelong relationships,” Marilyn said.

Professor Judson launched the career of many Ph.D. students; he inspired them to better understand insect behavior by investigating insect physiological control mechanisms.

Emeritus entomology professor Robert Washino, former department chair and former associate dean, UC Davis College of Agricultural and Environmental Sciences, recalled that “Charles Judson was one of the newcomers who among others--Professors Norman Gary, George McClelland, Donald McLean-- joined the department in the early sixties and introduced greater emphases on physiology and behavior into the teaching and research program that previously stressed taxonomy and regulatory entomology.”

“Charles was one of the first faculty members in the department to be awarded a National Institutes of Health grant for his work on mosquito egg physiology,” Washino said. “I believe Charlie's calm and deliberate manner of successfully carrying out his teaching, research and public service made him a most valuable member of the department. One of Charlie's most productive graduate students, Henry Hagedorn, went on to make major contributions in mosquito reproductive physiology at the University of Arizona at Tucson.”

Hagedorn completed a Ph.D. with Professor Judson in 1970 and then went on to become internationally recognized for his research that led to the development of a model for understanding the multiple roles of hormones in the development of mosquito eggs.

Many of Professor Judson's colleagues praised him as an excellent scientist and wonderful friend. Said distinguished professor of entomology James R. Carey: "Charlie Judson radiated graciousness, trust and respect, and personified everything good in a university scientist, mentor, and teacher. He not only helped shape our department in its early days, but also set a very high bar for personal decency and professional integrity. Colleagues like Charlie are hard to find, difficult to lose, and impossible to forget."

Albert Grigarick, UC Davis emeritus professor of entomology, said: “Charlie was a friend, colleague, and neighbor for nearly 50 years. He was always willing to help you in your academic endeavors or backyard projects.  He will be missed by the many students that sought his scientific knowledge and friendly advice.”

Former graduate student Tom Batchelor, who focused his research on the nature of physiological lesions in insects caused by radiation, was Professor Judson's last graduate student. “Gaining control of mosquitoes to reduce their impact on human health has been at the heart of many research programs for decades,” said Batchelor, who now lives in New Zealand. “Professor Judson's research contributed to a better understanding of specific aspects of their feeding and oviposition behavior, and the physiological control mechanisms underpinning this behavior.”

Throughout his academic career, Professor Judson focused his research on the stimuli that caused mosquito eggs to hatch. “Using the eggs of Aedes aegypti and A. nicromaculis, he found that mosquito eggs in water under low oxygen conditions hatched readily,” Batchelor said. “Just the act of decreasing the oxygen concentration, and not just a low oxygen concentration itself, proved to be a powerful hatching stimulus. He also examined the ability of various compounds to penetrate the egg of the mosquito, since mosquito eggs are rather impermeable to water and several chemicals. His research on the ovicidal qualities of these compounds led to further research on better ways to control mosquitoes at the egg stage.”

Another aspect of his research explored the physiological basis underlying a mated female's predisposition to oviposit. Professor Judson showed oviposition was stimulated by a “biochemical signal” emitted by the accessory gland of the male mosquito, Batchelor pointed out. “Virgin females tend to retain their eggs and not oviposit, but they will oviposit if a male accessory gland is implanted into them. Similarly, Professor Judson showed that mosquito biting behavior coincided with the terminal phases of each egg cycle, and that fewer mated females fed at these times than virgin females.”

As an aside, Batchelor said he sometimes saw Professor Judson feeding his laboratory mosquitoes by putting his whole arm in their cage—“when the hamster was having a day off.” Professor Judson commented that feeding the mosquitoes this way was not putting his health at risk, “but rather the health of the mosquitoes exposed to low levels of nicotine and alcohol residues in his blood!” Batchelor recalled.

Entomologist Fran Keller, who served as Professor Judson's teaching assistant for his insect physiology class while working toward her doctorate in entomology, recalled: “Charlie was always happy to see students. At the Department of Entomology's barbecues, I remember how he would make the rounds and make sure he talked with all the students. My interactions with him as a TA for insect physiology were always informative, relaxed and positive. He enjoyed teaching and sharing his knowledge with students. He was a thoughtful, caring and compassionate mentor.”

“Charlie also served on my oral exam committee,” Keller said. “He had a way of confronting you with questions that made you think. As a mentor, that is what you are supposed to do. As a physiologist, he asked me, ‘Why do you want to work so hard on beetles doing a revision when somebody is just going to come along and change it all around in 50 years? You taxonomists always seem to be changing names,' and as a taxonomist, I answered, ‘Well, if I do it correctly, then changes will be made when there are new discoveries, so I am providing a foundation for future work.' And he replied, 'Okay, that makes sense.'  He wanted students to think about their future and what they were doing. To say Charlie was concerned for and kind to his students would be an understatement. I am very saddened by his passing and I will miss his presence as a friend and mentor.”

In addition to his teaching and research, Professor Judson was actively involved in the community, working with Habitat for Humanity, Yolo County Court Appointed Special Advocates (CASA), Yolo County Grand Jury, Yolo Family Service Agency, Sierra Club, Short-Term Emergency Aid Committee (STEAC), Senior Learning Unlimited, and All Things Right and Relevant. 

His other interests included politics, gardening, photography, woodworking and the building of wooden boats. He and his family spent many hours on Loon Lake, the Sierras, in his hand-built vessels, including kayaks, canoes and dinghies. His involvement with the Traditional Small Craft Association, his family said, “led to wonderful friendships, as well as involvement in Seeds of Learning, through which he spent several summers in El Salvador.”

His parents met on the UC Davis campus when both were students at UC Berkeley and were required to spend a year at “The Farm” because of their major. His father helped plant the black walnuts on Russell Boulevard.

At his request, no memorial service will be held. The family will gather during the holidays to scatter his ashes in Monterey Dunes, sharing fond memories of beachcombing, digging holes in the sand, and just being together as a close-knit family.

Professor Judson was a strong believer in “walking the walk” by acting on his integrity and beliefs, his family said. In lieu of flowers, he would ask that people “pay it forward” by reaching out to another person or group.

(See Robert Washino’s interview of Charles Judson on UC Davis video website at

Kathy Keatley Garvey
Communications Specialist
UC Davis Department of Entomology and Nematology
Published on: August 14, 2015