Predation of Acacia seeds by bruchid beetles and its relationto altitudinal gradient in south-western Saudi Arabia

A study of the distribution of Acacia trees and bruchid seed beetles in south-western Saudi Arabia revealed that different host-insect pairs occupied a specific range along an altitudinal gradient. Between sea level and 1750 m.a.s.l., the following host-insect pairs were recorded: A. tortilis B. aurivilli; A. tortilis—B. sahelicus; A. ehrenbergiana-B. saudicus; A. asak, A. hamulosa, A. oerfota, and A. seyal are all attacked by different species of Bruchidius. Between 1750 and 2500m, the following host-insect pairs were recorded: A. negrii-B. arabius; A. gerrardii-B. arabius. The rate of seed predation varied among Acacia spp, but the highest were recorded in A. tortilis and A. ehrenbergiana