Relative distribution of ant species in cocoa plantations in Papua New Guinea
(1) In Papua New Guinea the most important cocoa pest, Pantorhytes szentivanyi, is controlled by the ant Anoplolepis longipes, while in Ghana Oecophylla longinoda controls cocoa capsids. The paper describes organization of the ant fauna of Papua New Guinea cocoa and compares it with that found in Ghanaian cocoa. (2) Two methods of sampling canopy ants were used: pyrethrum knockdowns and hand-catching. Both methods gave essentially the same results. Hand-catching in a 1-m2 quadrat was used to sample ants on the ground. (3) 200 knockdowns, 135 hand-caught and sixty quadrat samples took a total of 121 species. These species and their frequencies of occurrence in each set of samples are listed. (4) Ant species richness was greater on the ground than in the canopy. A greater range of microhabitats on the ground, and the ease with which indigenous ants could invade the new cocoa ground habitat are suggested as explanations. (5) The mosaic distribution pattern of dominant ants found elsewhere was confirmed in the cocoa. The dominant species Anoplolepis longipes and Technomyrmex albipes were abundant, Oecophylla smaragdina moderately so, and Crematogaster sp. R114 was scarce in the canopy. On the ground, dominants Brachyponera croceicornis, Pheidole megacephala, Odontomachus simillimus and Rhytidoponera araneoides were moderately abundant in addition to the common canopy dominants. (6) Specific communities of non-dominant ants appeared to be associated with each dominant in the canopy. The number of species in each community seemed to be related to the degree of specialization of the dominant with which it was associated. Technomyrmex albipes had fewest species in its community, and it was the only dominant to nest in a potentially limiting resource, dead wood. (7) T. albipes and Oecophylla smaragdina were not mutually exclusive, and it is suggested that competition between them was slight partly because of the difference in size of their foragers. (8) Ant species diversity in the canopy of cocoa was greater in Ghana than in Papua New Guinea, probably because cocoa in the former is grown in thinned forest. (9) Dominant ants in Ghana were all indigenous, while the two commonest dominants in Papua New Guinea were tramp species. (10) In both countries the dominant ant species most positively associated with pest situations in the one which nests in dead wood
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| Format: | biblioteca |
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1975
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| Subjects: | THEOBROMA CACAO, FORMICIDAE, DISTRIBUCION NATURAL, MUESTREO, METODOS, PAPUA NUEVA GUINEA, |
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