CHEMICAL SIGNALS FOR MANAGING INSECTS
Title: Obituary for Jan van der Pers
| Minks, Albert - ZETTEN, THE NETHERLANDS |
| Visser, Hans - BENNEKOM, THE NETHERLANDS |
Submitted to: Entomologia Experimentalis et Applicata
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 20, 2006
Publication Date: December 1, 2006
Citation: Minks, A., Visser, H., Dickens, J.C. 2006. Obituary for Jan van der Pers. Entomologia Experimentalis et Applicata, 121:189-190.
After a short but valiant struggle against cancer, Jan van der Pers died on 29 April, 2006 in the hospital in Hilversum, The Netherlands, close to his home. Our conversations with Jan during the last months of his life showed the remarkable strength and positive attitude typical of him. Discussions about science, the classics, and the nature of life, as well as shared memories, made these conversations as pleasant and stimulating as always.
Jan started his career in insect chemoreception with his PhD research at the University of Groningen in the group of Cees den Otter, receiving his PhD in 1980. As part of a national research programme on the speciation of Yponomeuta moth species initiated by the late Wim Herrebout, Jan investigated the olfactory receptors of a range of closely related Yponomeuta moth species by their morphology and electrophysiological responses to sex pheromones and plant odour components. Jan combined an inventive mind with extensive technical skills. He made glass knives for cutting off the tip of tiny single olfactory sensilla in order to record responses of neurons housed within them. In order to photograph the whole circumference of an antennal segment using a scanning electron microscope, he constructed a special specimen holder. Devices such as these were products from his mechanical workshop at home, a private business registered in 1970 and playfully called Murphy Developments in recognition of Murphy’s Law. In these early years, equipment for the electrophysiological recording of neuron responses in insects was very expensive and of poor quality. Jan surmounted these difficulties by developing his own amplifiers and recording devices. For example, he constructed a real-time electronic spike discriminator that preceded the software tools currently available.
In 1981, Jan moved to Sweden for a postdoctoral position in the pheromone group at Lund University. Here, he built an electrophysiological set-up for recording of moth responses to sex pheromones. Most essential components of this unit were made by Jan himself: micromanipulators, amplifier, and odour delivery equipment. He cooperated in Lund with pheromone chemists such as Christer Löfstedt and Bill Hansson. The latter was his first and only student. We all know that Jan was very straightforward and that he preferred the practical aspects of science to the paperwork and bureaucracy that are an inevitable part of large institutions such as universities. He returned to the Netherlands in 1983 to devote himself entirely (thanks to the help of his wife, Bonnie King) to the work he enjoyed in his own independent company. The name of the company was changed from Murphy Developments to SYNTECH several years later. SYNTECH has since specialized in the development and production of biophysical instrumentation, particularly for the study of insect chemoreception.
Jan ran his company with two major goals: to produce instruments that were easy to use (for everybody, ‘ . . . even entomologists!’) and to develop high-tech Instruments (for the specialists). He was less interested in the most obvious business goal of making money. Jan liked to say, ‘I don’t sell, people buy’. If a scientist could not afford to buy his instruments, Jan came up with a solution that allowed the research to progress nonetheless. In this way, Jan has probably been the largest private sponsor for the science of insect chemoreception. The number and variety of instruments he developed are incredible, considering he did everything by himself until a few years ago. The list of instruments contains among others: micromanipulators, electrode holders, amplifiers for electroantennogram (EAG/EAD) and single sensillum recordings (SSR), odour delivery devices, radar actometer systems, special taste probes, coupled GC-EAD and GC-SSR solutions (gas chromatograph connected to insect ‘detectors’ through a special transfer line), portable EAG recording units, and, recently, data acquisition systems (up to 16-channel) and servospheres. Nowadays, several instruments have been combined with finely tuned software such as for GC-EAD, spike recordings, and servosphere tracking. His last instrument, the servosphere (Trackspere LC-100), received the Mechatronics Trophy 2003. Jan was especially proud of this achievement, as he received recognition from other engineers.
Besides producing dedicated instruments, Jan gave invaluable advice to numerous scientists all over the world. In over 60 countries on every continent except Antarctica, one can find SYNTECH instruments being used by local researchers. The impact of his activities on the science of insect chemoreception is difficult to estimate but must be vast, considering the number of scientists who profit from his inventions. The following personal experience is given to illustrate Jan’s varied input.
In the early 90s Jan told one of us (AKM) that he had constructed a portable single sensillum recording (SSR)module that was suitable for use in the field. ‘An old dream has come true’, was Jan’s comment. ‘Direct measurements of the dynamics of pheromone plumes are now possible.’ As an electrophysiologist, Jan had spent most of his working time indoors, in the laboratory. He showed me the device, and although I did not understand all the details of his enthusiastic explanation, I was impressed by its simple and compact design (20 ''20 ''20 cm). Unique to this construction was the way in which the concurrent recording of both the activity from pheromone receptor cells and the air velocity in close proximity of the recording site were arranged, allowing a proper analysis of the pheromone plume structure and the pheromone perception by moths. After some try-outs in his garden in Hilversum, Jan modestly asked me if I would be interested in helping him with field testing. I readily accepted. During the following two summers, we made quite a number of field trips to the experimental orchard ‘De Schuilenburg’, not far from Wageningen, where many of the Dutch pheromone experiments have been conducted throughout the years. Jan thoroughly enjoyed working outside. For classical field workers, it must have been a funny sight to see Jan walking up and down from pheromone sources while carrying the module. During these exercises, the connected audio equipment produced grunting noises when recording the firing responses of the receptor cell activity from the pheromone plumes. We became really excited when the module appeared to function well and we were able to collect a nice set of data. In a relatively short time we had published some good papers.
Despite this success, Jan decided to abandon the project, concluding that the practical use of the SSR technique was still far from realization. Further study would require a major effort. As a researcher, Jan was challenged and would have liked to proceed, but he realized that he did not have enough time to make that effort: he had a steady stream of clients waiting for equipment! Yet he wanted to contribute to a better understanding of the mechanism of mating disruption. Soon he proudly came up with a compact (26 ''15 ''8 cm) lightweight (ca. 4 kg) EAG apparatus. This sensor was portable in the true sense. The signal processing electronics and all necessary components for conditioning of the antennal preparation were contained in this single unit: it was a marvel in its simplicity! We tested the performance of the EAG sensor in a series of recordings carried out in greenhouses fitted with pheromone dispensers for mating disruption purposes as well as in control greenhouses. Jan showed that he could move the sensor quickly from the pheromone-treated areas to the controls and back. Relative differences in pheromone concentration and changes in pheromone concentration were clearly demonstrated. The simple handling procedures of the sensor made routine measurements by field entomologists possible. Jan was really pleased with these po