Insects' Sex Scents Can Save Lives

This is shown by Björn Bohman at Kalmar University in Sweden in his dissertation “Identification, Synthesis, and Structure-activity Studies of Semiochemicals.” Under the supervision of Associate Professor Rikard Unelius, Björn Bohman, a chemist, has collaborated with biologists to find the compounds secreted by three different insects.

In South America there are the two blood-sucking triatomines Rhodnius prolixus and Triatoma brasliensis, which carry parasites that spread the deadly Chagas disease that affects millions of people in South America each year. By trying to identify the substances that the insects send out either to attract others of the same species or to alarm others about danger, it will be possible to control these insects.

Biologists have singled out the relevant glands in the insects. In his work Björn Bohman managed to identify several compounds that are found in these glands and then to prepare them synthetically in the laboratory. The objective is to be able to produce an inexpensive monitoring trap (such as a matchbox with a sticky strip and a scent) that people in exposed areas can have in their homes.

For the last five years he has been busy with three projects, one of which involves these triatomines in South America. Moreover he has worked with the lucerne weevil Sitona discoideus, which attacks alfalfa, and developed ways to stop damage from the gnawing of the pine weevil Hylobius abietis, which can be a major problem when clear-cut forests are replanted.

All of the isomers of a potential sex pheromone for the lucerne weevil, 5-hydroxy-4-methyl-3-heptanone, were synthesized using a method developed by Björn Bohman, who used vegetables or mushrooms to produce the desired compounds. This proved to be a both better and considerably simpler method than previously known methods.

Knowledge of insect pheromones and how they can be produced synthetically is important when it comes to finding effective ways to reduce the use of pesticides in agriculture, for example. With this knowledge it is possible, for one thing, to spread tiny amounts of the substance that the insect pests communicate with so that they can't find each other for mating or, the opposite way, to lure them into traps where they can be eliminated.