THE STENOBASIPTERON WIEDEMANNI (DIPTERA, NEMESTRINIDAE) POLLINATION GUILD IN EASTERN SOUTHERN AFRICA

摘要

Stenobasipteron wiedemanni, a long-proboscid nemestrinid fly, services a Guild of flowers distinct from the Prosoeca ganglbaueri pollination Guild in which it has previously been placed. The former fly is the recorded pollinator of 19 plant species in six families: the Acanthaceae, Balsaminaceae, Gesneriaceae, Iridaceae, Lamiaceae, and Orchidaceae. Stenobasipteron wiedemanni is a mainly forest-dwelling fly with a proboscis length of 19—30 mm. The plant species that are pollinated by this fly are also restricted to forest (or woodland) habitat along the eastern parts of southern Africa. The flowers of plants in this pollination Guild tend to have long, narrow nectaries and corollas in shades of purple, pink, mauve, pale blue, and white. Nectar is present in all species, pollination is diurnal, and most species have zygomorphic flowers with nectar guides. This pollination Guild is separated on the basis of the limitation of the fly, S. wiedemanni—and hence the plant species—to forest or closed-canopy habitat. Biogeographically, the S. wiedemanni Guild also occurs at lower altitudes in subtropical regions of southern Africa.