Influence of Cocoa Agro-Ecosystem on Fruit-Feeding Nymphalid Butterflies

Abstract

Bia Biosphere Reserve was surveyed, with fruit-baited traps and line transects running from the forest to an adjacent cocoa farm, to assess how habitat change affects fruit-feeding butterfly species composition. Species richness, diversity and similarity indices were all computed using the EstimateS software. Differences in species abundance were tested using the Mann-Whitney U test. A total of 1,356 individuals belonging to 88 species were trapped during the entire study period. All the individual butterflies were fruit feeders (nymphalids) belonging to six (6) subfamilies of Nymphalidae except one (Gamia bulchozi) and so was not included in the subsequent data analysis. The species richness and diversity of the forest were higher (75.11±1.3 and 17.98±1.25) than that of the
cocoa farm (69.55±1.28 and 15.61±1.17 respectively) and the similarity between the forest and the cocoa farm was very low (0.315). There were significant differences (P<0.05) between species recorded in the forest and the cocoa farm. A function of anthropogenic disturbances which caused differences in light penetration and habitat disturbance and fruit-feeding butterfly species habitat preference were some of the factors that were discussed. There were significant differences between fruit-feeding butterfly fauna composition in the forest and the cocoa farm and species composition was dependent on habitat type.

Journal of the Ghana Science Association Vol. 10 (2) 2008: pp. 145-158