Food, Feeding Ecology and Morphological Features Associated With Feeding of Four Co-Occurring Cyprinids (Pisces: Cyprinidae)

Abstract

1. The food, feeding ecology and morphological features associated with feeding of four co-occurring cyprinid fishes, namely Rasbora daniconius, Danio aequipinnatus, Puntius amphibius and Puntius dorsalis were investigated. 2. The diets of R. daniconius, D. aequipinnatus, P. amphibius and P. dorsalis consist of 33, 27, 23 and 27 identifiable plant species respectively, of higher plant leaves and animal matter. The composition of the diet of different size groups of the same species were also found to be different from each other. 3. The relative importance of the major taxonomic groups in the diet, computed by taking into consideration the size of the dietary material, indicate that in the two Puntius species the major contribution comes from the plant material in contrast to the other two cyprinids. 4. In R. daniconius and D. aequipinnatus the major component of the diet is insects accounting for 92.5% and 94.9% respectively while in the two Puntius species crustaceans constitute the major animal material of the diet. 5. Morphological features such as the shape and position of the mouth, the nature, number, the size and spacing of gill rakers, teeth and the mean relative gut length of the four cyprinids are shown to be correlated to their feeding habits and ecology. 6. The differences in the diets are shown to be related to their feeding ecology and the importance of such dietary separation as well as overlap are discussed in the light of the Gausian Principle of Ecological Exclusion. 7. On the basis of the present and earlier published data it is hypothesized that endemic species tend to show more clear and well defined niche segregation and ecological adaptations as compared to indigenous species, which have come from the mainland.