Title: Research Entomologist
Company: United States Department of Agriculture
Location: Gainesville, Florida, United States
Marion Sidney Mayer, PhD, Research Entomologist at the United States Department of Agriculture, has been recognized by Marquis Who’s Who Top Scientists for dedication, achievements, and leadership in entomology.
Long fascinated by entomology, Dr. Mayer earned a Bachelor of Science from Louisiana State University in 1957. Following this accomplishment, he joined the U.S. Army Reserves in 1958, and remained active as a reservist until 1964. During this time, he matriculated at Texas A&M University, from which he earned a Master of Science in 1961 and a Doctor of Philosophy in 1963. Dr. Mayer’s doctoral dissertation served as an assessment on the efficacy of using radioactive isotopes to locate overwintered boll weevils, which yielded evidence that the weevils would begin to die seven days following their initial exposure.
After Dr. Mayer’s initial employment in 1973 by the U.S. Department of Agriculture in Gainesville, he began studying the effects of human airborne odors on mosquito olfactory mediated behavior and is proud that his particular research group performed all of its testing correctly. Additionally, he was the first to show that mosquito eggs hatch rates exponentially decline relative to the level of environmental water immersion. Dr. Mayer also demonstrated the existence of a hydrocarbon-based compound that is highly attractive to houseflies, which is now used in many commercial traps.
Throughout the course of his long tenure in research, Dr. Mayer served as an entomologist for the U.S. Department of Agriculture from 1963 until his retirement in 2000. Dr. Mayer’s accomplishments included assessing the use of radioactive P-32 to locate overwintered boll weevils in fields. He used histological methods to show that the effects of radiation on the boll weevil were first manifested in cells of their gut. He later began working on mosquito olfactory mediated behaviors to human airborne odors. He coincidentally was the first to show that mosquito egg-hatch declines exponentially relative to the number of water immersions. He discovered that Folch washes of housefly cage covers contained a hitherto unknown compound that attracted male houseflies. His further fractionations of this extract revealed that the active agent was a hydrocarbon compound and a large amount of active agent obtained contributed significantly to the easily identified compound, (Z)-9-tricosene now used in many commercial housefly baits. Coincident studies by Dr. Mayer of agents that arrest house fly movement at food sources, “arrestants”, one compound was found to be far better than moist sugar, the once best arrestant. Structure-to-activity relationships among other active arrestants were made. During this time Dr. Mayer learned to use electrophysiological methods to record from insect antennal sensilla and discovered a human – breath-responsive olfactory receptor neuron on the antenna of the “kissing bug” (Triatoma infestans). Because of his ability to record responses from individual insect olfactory receptor cells, Dr. Mayer was moved to a new laboratory built by the USDA in 1970 to study sex pheromones of moths. From his previous studies of olfactory and taste-mediated behaviors by mosquitoes, houseflies and kissing bugs he knew that it was imperative for the studies to measure and use at known airborne concentrations that represent those found in nature. During that time, he realized that a better method of dispensing the olfactants than those commonly used by simply blew air overweights of odorants from papers resulting in unknown emission rates. His team designed and developed a unique all-glass apparatus that was calibrated by measuring the emission of radio-labeled sex pheromone (Z-7-dodecenyl acetate, ZDA) of Trichoplusia ni (Hubner) (T. ni). This device thus enabled us to measure responses of individual antennal receptor cells to pheromonal stimuli at measured airborne concentrations. With two colleagues at the Worcester Research Foundation, we found two types of sensillar neurons on T. ni antenna that responded to ZDA and other similar compounds found in the female emission. These neurons responded to several other compounds found in the female emission but the cells were responsive to these other components at higher airborne concentrations than ZDA. During this time the physical principles of pheromonedeposition on the antenna were described. Further studies by captures in field traps showed that admixture with ZDA with any and all of these pheromone components reduced captures confirming that only ZDA was the active agent. Verification and validation of all of these prior measures and precautions were validated at natural airborne concentrations in a ZDA – inundated cotton field where mating of tethered female moths was totally prevented. The measured airborne ZDA concentrations in the field were near or at the detection level by individual antennal receptor cells. This ultimate combination of our singular methodology and data has a significant bearing on all studies of insect pheromone-activated behaviors, field trapping and peripheral/central nervous systems that are based on paper-dosed methodology up to 2000 when she retired. (Dr. Mayer wants to recognize the following people who contributed significantly to all the pheromone studies: His friends, Drs. Robert O’Connell, Alan Grant, Richard Mankin and his valued technical assistant, Mrs. Jane Sharp.)
During the span of his career, he notably authored a book chapter on behalf of one of his colleagues, “Insect Pheromones and Sex Attractants” in 1990. As a testament to his success, Dr. Mayer received an Albert Nelson Marquis Lifetime Achievement Award in 2020. He is also listed in the 24th and 25th editions of Who’s Who in the South and Southwest.
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