Ants remove virtually all western myall (Acacia papyrocarpa Benth.)
seeds at Middleback, South Australia.
Ireland, C. and Andrew, M. H.
Botany Department, University of Adelaide, Adelaide, SA 5005, Australia.
Australian Journal of Ecology. 1995. 20: 565-570
CAB Abstract 960601108
Ants can have a profound effect on the number of seeds present in the seed-bank. The removal of seeds of an important arid zone tree species, the western myall (Acacia papyrocarpa), was investigated at a site in South Australia. The species has seed characteristics typical of other Acacia species: a hard seed-coat and a small, white aril or elaiosome; the latter is reported to be attractive to ants. An experiment was conducted to see how rapidly and completely the seeds would be removed under various caging treatments. Observations were also made to discover the major seed removers and the fate of the seeds. Seed removal was rapid (<12 h) and was almost entirely by ants, and while the results were not conclusive, it is suggested that much of the seed supply is effectively destroyed by seed harvester ants which thus act as true granivores, not seed dispersers. Whether this matters for western myall in the long term is uncertain because the species is long-lived; rare but successful recruitment events may well be sufficient for its long-term survival.