Forests Of Cameroon Research Articles

Cercocebus torquatus: Adaptive feeding and ranging behaviors related to seasonal fluctuations of food resources in the tropical rain forest of south-western Cameroon

The feeding and ranging behaviors of mangabeys,Cercocebus torquatus torquatusKerr (1792), were studied over two periods for a total of 15 months in south-western Cameroon between 1983 and 1986. The mangabeys showed stable food acquisition, mainly of fruits produced by canopy trees. Their ranging area, especially the core area, shifted seasonally. The fruiting trees revealed a clumped distribution in space, and provided a fluctuating food resource for frugivores, including the mangabeys. The core area of the mangabeys possibly shifted due to the spatial distribution of fruiting trees, their highest ranking food items. Mangabeys are well adapted to such a fluctuating food distribution, regulating their ranging behaviors to ensure stable food acquisition.

3-Hydroxyuridine, an allelopathic factor of an African tree, Baillonella toxisperma

A plant growth inhibitor was isolated from Baillonella toxisperma, a plant which may cause an allelopathic effect in the tropical rain forest of Cameroon. From spectral and chemical evidence, the inhibitor was identified as 3-hydroxyuridine. It inhibited both hypocotyl and root growth of cucumber and radish seedlings, and also inhibited root growth of rice seedlings, but not sheath growth. The foliar treatment of 3-hydroxyuridine exhibited inhibitory effects on the growth of a wide variety of weeds; however, it was quite ineffective against the growth of the crop plant, Zea mays. The strong plant growth inhibitory activity, together with the occurrence in most parts of the tree at high levels, indicated that 3-hydroxyuridine may be involved in the allelopathy of the tree.

Utilization of fruiting trees by monkeys as analyzed from feeding traces under fruiting trees in the tropical rain forest of Cameroon

Individual trees of the food species of monkeys were identified by placing plastic tapes with an identification number on them in the tropical rain forest of Cameroon, West Africa. In order to determine the use of the feeding trees by monkeys, the ground under each of the trees was checked at least once a week to see if there were any fallen fruits or traces of feeding on fruits. Some fruit species were not fed on by either monkeys or large arboreal squirrels. Among the food species common to both the monkeys and large squirrels, a larger proportion in terms of quantity in each species was mainly eaten by the monkeys except in the case of super-abundantly fruit producing species. The monkeys and large arboreal squirrels were well segregated in their diets. Larger proportions (more than 85% for most of the monkeys' major foods) of fruits of larger sizes were made to fall on the ground by the monkeys and squirrels. The monkeys displayed a tendency to visit fruiting trees rather evenly (even rate of visit = even frequency of visit/duration of fruiting) not ignoring any area of the home range, although a small difference in this tendency was observed between the two study periods, one an abundant season and the other a poor fruiting season. On average, one associated polyspecific group of monkeys encountered only 14 fruiting trees per day. On the other hand, fruits were available all around the year, as the fruiting periods of different tree species were widely distributed around the year, or the fruiting periods of some species were very long. Although the monkeys are able to depend heavily on fruits, the quantity of fruits is not so great. The population size of monkeys is well balanced with the available food supply in the tropical rain forest of West Africa.

カメルーン熱帯多雨林に生物活性植物を求めて

カメルーン熱帯多雨林に生物活性植物を求めて

The contributions of different age groups to the transmission of onchocerciasis in a cameroon forest village

The population of 3 rain-forest villages, heavily infected with O. volvulus, were divided into age and sex groups. Samples from each group were studied with regard to total numbers of nodules; concentrations of mf. per mg. in calf skin snips; intake of microfilariae by, and numbers of infective larvae developing in, groups of S. damnosum fed on their lower legs. The theoretical contribution of each age and sex group to the over-all transmission of O. volvulus in the village is calculated, and the value predicted by experiment for the whole village is compared with the value recorded under natural conditions from dissections of wild flies.