Labelling of the tsetse fly Glossina palpalis palpalis by activable elements

Tsetse flies of the species Glossina palpalis palpalis Rob. Desv. were subjected to various treatments with an aim of achieving labelling with the activable stable elements dysprosium, europium or lanthanum. The substances were injected as chlorides or nitrates, they were added to the food of the flies or applied externally to pupae or adults by dipping, or by spraying with the solutions. Feeding with the labelling substance was in principle the easiest method to handle a large number of flies. Only lanthanum salts have been tested so far and it was found that they were excreted relatively fast. They gave detectable labelling for 4 days after application only. The spraying of adults with lanthanum-containing aerosols was a technique which could be used on a mass-production scale. A fairly homogeneous degree of labelling was achieved, which was so high that during mating a clearly measurable amount of lanthanum was transferred from the labelled male to the female. (Auth.)