Annotated records of blackfly (Diptera: Simuliidae) distribution in southern Africa

Regional and catchment distributions of blackflies (Diptera: Simuliidae) in southern Africa are presented and discussed relative to the biology and environmental preferences of the aquatic stages. Distribution data are based on all known records, both published and unpublished. Thirty nine blackfly species are recorded: 13 are widespread with no particular geographical affinities, 18 are restricted in distribution and eight are rare. Distributions are closely related to downstream changes in rivers, although eight species are endemic to parts of the southern and southwestern Cape, while eight are absent from the southern and southwestern Cape. The most common and widespread species are Simulium nigritarse s.l. Coquillett, S. medusaeforme Pomeroy, S. damnosum s.l, Theobald and S, adersi Pomeroy, all of which are associated with medium-sized rivers, and all of which are likely to be species complexes. Seven specles occur in large rivers, three of which are restricted to large rivers, A further six species were recorded in temporary streams, Some species, such as S, medusae forme, inhabit a wide range of water-quality conditions, but at least five species are restricted to excellent-quality water, and three species were typically found in polluted water: Temporal changes in blackfly distribution and abundance are related to long term drought/flood cycles, as well as increased river regulation and catchment development. The mammalophillc S, damnosum s.l. is recorded for the first time from the southwestern Cape, and S, lumbwanum de Meillon, a specles whose larvae and pupae are phoretic on certain mayfly nymphs, is recorded for the first time from South Africa and Swaziland,