Ant mosaic in oil palm plantations of the southwest province of Cameroon: Impact on leaf miner beetle (Coleoptera: Chrysomelidae)

A study was conducted to determine the distribution of ants in the crowns of oil palms on 2 plantations (Mpundu and Mondoni) in southwest Cameroon (a total of 615 oil palms). Six dominant species [Crematogaster gabonensis (Emery), Tetramorium aculeatum (Mayr), Oecophylla longinoda (Latreille), Monomorium sp., Pheidole megacephala (F.), and Paratrechina sp.] were distributed in a mosaic pattern. C. gabonensis was the most frequent ant species in Mpundu (86% of the oil palms), whereas in Mondoni it was in competition with T. aculeatum (45.8% of the oil palms of the 6 parcels of land) and was recorded at a lower rate (51.1%). On 3 parcels in Mondoni, T. aculeatum was the most frequent; whereas on 2 others, C. gabonensis was the most frequent, and in the last parcel these 2 species were evenly distributed. Therefore, oil palm plantations shelter dominant ant mosaics as do plantations of other trees of economic interest and tropical forests. The percentages of oil palms occupied by one or the other of the 2 most frequent dominant ants recorded in 12 parcels were compared with the rate of attack by Coelaemenodera minuta Uhmann. Low rates of attack by the hispine beetle were recorded for parcels where the percentages of oil palms occupied by C. gabonensis were high; the opposite was true for parcels where the percentages of oil palms occupied by T. aculeatum were high.