Acacia seed predation by bruchids in an African savanna ecosystem.
Abstract
In field studies conducted in Africa between July 1991 and November 1992, Acacia tortilis, A. nilotica and A. mellifera seeds on the ground suffered greater bruchid infestation than seeds within canopy-held pods. Seeds of indehiscent and dehiscent Acacia species showed no difference in the rate of bruchid infestation. More bruchid species attacked seeds of indehiscent (A. nilotica, A. tortilis, A. hebeclada and A. robusta) than dehiscent (A. karroo, A. mellifera and A. caffra) species. Bruchid infestation differed between A. tortilis trees, and for A. tortilis and A. hebeclada, differed between years. There was no difference in bruchid attack on A. nilotica between years. Stored Acacia seeds were infested more than fresh seeds. These results have important implications for re-afforestation programmes with Acacia trees in Africa. Pods should be collected from the canopies of Acacia exhibiting low bruchid infestation, the length of seed storage should be minimized and seeds susceptible to the same bruchid species should not be stored together.