Reminiscence of the Early Days

WENDELL L. ROELOFS

BECOMING AN ENTOMOLOGIST

CHALLENGES TO PHEROMONE IDENTIFICATIONS

Oak leafroller, Archips semiferanus (Tortricidae) European corn borer, Ostrinia nubilalis (Crambidae) Codling moth, Laspeyresia pomonella (Tortricidae) Sex attractants used as a taxonomic tool

CHALLENGES TO BEHAVIORAL STUDIES

Is a sex attractant really an attractant? Are all emitted compounds really pheromone components? Blend versus individual component roles

THE NEXT PHASE

REFERENCES CITED

Becoming an Entomologist

One of the hottest topics at Entomological Society of America meetings (ESA) in the mid-1960s was anything to do with insect pheromones. The recent decoding of the silkworm moth, Bombyx mori (Bombycidae), pheromone by German scientists (Butenandt et al. 1959) after three decades of research showed that it was possible to unravel the mysteries of these mating messages. The term "pheromone" had recently been coined (Karlson and Luscher 1959) to describe these chemical signals, and much discussion was centered on the exact meaning of this new term. A plea in Rachel Carson's book Silent Spring to develop insecticide alternatives also helped to generate funds for research on pheromones and their use in pest monitoring and management programs. The idea for the practical use of pheromones was proposed in 1882 by J. A. Lintner, the first New York state entomologist (Lintner 1882). He had observed the great attraction that female Promethea moths had for conspecific males from long distances and wrote: "Can not chemistry come to the aid of the economic entomologist, in furnishing at moderate cost, the odorous substances needed? Is the imitation of some of the more powerful animal secretions impracticable?" Paper sessions and night discussions at the ESA were packed as the few scientists involved in the pheromone field debated questions regarding pheromones and their practical use. It was my great fortune to come into this scene in 1965 as part of a new thrust by the Entomology Department of Cornell University at the New York State Agricultural Experiment Station in Geneva to develop a research program on pheromones of moth pest species.

Paul Chapman, the Chair of the department, felt that the fastest route into the pheromone field was to hire a chemist. He was a wise man and elicited the help of the renowned chemist at Cornell, Jerry Meinwald, to send out the position statement to his colleagues. My postdoctoral advisor at MIT got the statement and showed it to me. Although I had no training in entomology, I was intrigued by the possibility of conducting research on pheromones and applied for the position and got it. The search committee must have been impressed with my PhD thesis on "Cyclization of ylidenemalononitriles" in Organic Chemistry from Indiana University.

The entomologists at Geneva were eager to collaborate with me and I quickly set up a project on an apple pest, the red-banded leafroller moth, Argyrotaenia velutinana (Tortricidae), which had become resistant to the current pesticides and had become a major pest. Another project, which was funded by the NSF, was on the giant cecropia moth, Hyalophora cecropia (Saturniidae). This species was being mass reared by a fellow faculty member, Frederick Taschenberg, at the Fredonia Research Laboratory and was included in the research since it was a very large insect and thought to be an easy subject for pheromone identification. It turned out that the cecropia moth has very little stored pheromone, and the chemical structure apparently so complex that so far it has eluded all efforts on its identity.

To guide our research there was little information on pheromone structures or how to identify them. After the publication of the silkworm moth pheromone in 1959, Milt Silverstein and Dave Wood reported (Silverstein et al. 1966) on a chemical blend of three compounds for a bark beetle, and then Bob Berger (1966) published the pheromone of the cabbage looper moth, Trichoplusia ni (Noctuidae) as (Z)-7-dodecenyl acetate (Z7-12Ac). With little information available on how to identify pheromones, I decided to take a trip to the USDA labs in Washington, DC, to get up-to-date on methodology since the scientists there had been involved for years with the pheromones of a number of moth...