Abstract
On Mahé in the Seychelles, Anoplolepis longipes (Jerd.) is a pest, mainly because of the nuisance it causes to man and domestic animals but also because it increases the numbers of sap-feeding insects and the occurrence of sooty mould on plants. The most important sap insect associated with sooty mould on citrus and cinnamon was Ceroplastes rubens Mask., the numbers of which sometimes increased a hundredfold in the presence of A. longipes, and up to 90% of leaves were infected with sooty mould. The rapid population expansion of the ant on Mahé prior to 1973 has since slowed down, and infestations in some areas have diminished, possibly because of a decreasing source of protein. Movement of ant-infested material has initiated secondary infestations, which are difficult to eradicate once established. The ant is not considered a threat to conservation as differences between the fauna in infested and uninfested areas tend to be quantitative rather than qualitative. Attempts to eradicate the ant on Mahé would be costly and inappropriate. The use of toxic baits and sprays is recommended only where ants become a domestic nuisance, threaten productivity or reach Other islands in the Seychelles group.