Transmission of Herpetomonas in Laboratory Populations of Drosophila melanogaster

Methods of transmission and the effects of temperature and mites on ageledeme development of Herpetomonas were examined in populations of Drosophila melanogaster maintained in the laboratory. Herpetomonas was observed in feces of infected adults taken from population cages and in the vomitus of clean flies shortly after feeding on a saline suspension of flagellates. Free-swimming flagellates were found in the moist areas of food cups. Adult D. melanogaster became infected when they fed on flagellates taken from the endoperitrophic space, the ectoperitrophic space or the Malpighian tubules. At 25°C the flagellates infected approximately 90% of the host population within 20 days. The high transmission rate was prematurely disrupted if host populations were subjected to changes in temperature. Free-swimming flagellates did not appear to be affected at these temperature changes. Food mites (Tyrophagus) established in the growth media of the fly nearly eliminated the Herpetomonas from Drosophila populations.