Abstract
A population of Slmulium rugglesi was labelled with P32 by allowing individuals to feed on domestic ducks previously injected with this isotope. Flies that fed on these ducks from June 9-15 were recovered as late as July 12, 28 days after their last possible feeding on labelled ducks. Many rugglesi returned for another blood meal 5-7 days following the previous one; the volume of blood ingested at a meal averaged 1.9 (0.50-3.6) mm3. Some individuals were recovered at a site 2 miles from the marking site in a direct line but approximately 6 miles by water, this distance was covered in 5-12 days; marked flies moved with and against the prevailing winds and water currents. The large proportion of labelled to unlabelled flies (503/3747) collected in samples suggested that a small population of rugglesi was involved.