Predation of Seeds of Acacia Tortilis by Insects

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Abstract
Seed predation in the seed crop of individual trees of Acacia tortilis subsp. heteracantha in a tree savanna in Botswana was examined for three successive years. The degree of seed parasitism varied strongly between trees and years in a range from 10 to 82%. The bruchid beetles, Bruchidius albosparsus, B. aurivillii and B. rubicundus were the most significant seed predators, followed by a herbivorous hymenopteran Oedaule sp. The less frequent bruchids were B. petechialis, B. spadiceus and Caryedon sp. Only a small part of the bruchids, varying from 0% to 4.7% were infested by hymenopterans, the most common being Metriocharis nr. silvestri. Due to the high degree of cotyledons and radicula damage by these insects, attacked seeds had no advantage in germination compared with healthy seeds.