Major Dry Season Research Articles

Assessment of body linear measurements of semi-intensively managed Bunaji calves raised during major dry season in the derived savanna zone of Nigeria

Survival of semi-intensively managed cattle during dry season is critical towards their successful development. Cattle are of large size that obviously require high volume of feeds, for sustenance and productive purposes. A completely randomized design study over a period of three months during the major dry season (January to March) was carried out. The mean body measurements [chest girth (CG), body length (BL), body circumference (BC), tail length (TL), height at withers (HW) and body weights (BW)] were monitored fortnightly. The calves were allowed to graze in the morning, between 7.00 - 11.00 h and concentrate feed of 2 kg/day was offered in the afternoon on daily basis. Results from the study showed that the all the body measurements for the males increased till 6th week of the study, decreased till 9th week and thereafter increased till the 12th week. The estimated body weight for the males were 113.27 kg and 118.16 kg for the females at the end of the study. The mean CG was 122.89± 3.54 cm, BC was 132.41± 4.45 cm, TL was 81.74 ±2.01 cm, BL 89.54 ± 2.01 cm, HW 102.24 ± 3.22 cm and BW was 125.04 ± 2.89 kg. The correlation coefficient values were generally positive and significant. Highest positive correlations with significant differences were observed in all the parameters except for CG and BL (r= -0.07); and BL and HW (r= -0.57) which were negatively correlated. It was concluded that Bunaji calves would survive remarkably, with improved body measurements and weight gain if managed semi-intensively with available forage and concentrate during the dry season.

NATURAL DIET OF AMNIRANA ALBOLABRIS (HALLOWELL, 1856), A FROG SPECIE FROM BANCO NATIONAL PARK (COTE DIVOIRE)

We have established the natural diet of Amnirana albolabris from the Banco National Park (Cote dIvoire), through this study. Firstly, a general analysis of prey composition in the stomach of 238 specimens (obtained by the force-feeding technique) has been done, and secondly, according to the age, sex of specimens, climatic seasons, and sampling sites. Nine categories of prey (Insects, Arachnids, Annelids, Molluscs, Myriapods, Crustaceans, animal debris, macrophytes, and undetermined prey) have been identified in the diet of this species of frog. Adults diet is statistically different from juvenile one. However, males and females consume the same foods. In terms of the climatic seasons, the foods consumed during the long rainy season differ from those during the short dry season. Similarly, the foods eaten during the major dry season differ from those consumed by this frog during the minor dry season. At the spatial level, the diet of this species does not differ significantly from one habitat to another. The diet composition of Amnirana albolabris revealed that this frog species has an omnivorous diet with an insectivorous tendency in Banco National Park.

Rapid dung removal by beetles suggests higher duiker densities in Central African rainforests

AbstractFor many mammal species, converting dung density into population density requires accurate estimates of defaecation rate and dung survival time. The latter parameter probably varies seasonally. In Nki National Park, south-east Cameroon, we monitored 216 dung piles of the blue duiker Philantomba monticola and 373 of the red duiker group (Cephalophus spp.), major game animals in Central Africa, and estimated dung survival time across seasons. Mean survival time was 6.83 days in the major dry season and 1.21–1.81 in other seasons for the blue duiker, and 7.37 and 1.53–4.05 for red duikers, lower than the values conventionally used for density estimations in Central Africa (i.e. 18 days for the blue duiker and 21 days for red duikers). Overall, beetles removed half of the dung within 1 day of deposition. However, the proportion of dung piles that beetles removed was significantly lower in the major dry season, and other dung piles remained longer until they disappeared as a result of other factors. As shorter dung survival time results in higher estimates of population density, our findings imply that in forests with intense beetle activity, duiker densities are higher than those based on the conventional values of dung survival time. Duiker densities and dung survival time should be estimated simultaneously. To minimize the bias introduced by rapid removal of fresh dung by beetles, only fresh dung (< 3 hours old) should be monitored when estimating mean dung survival time.

Risk factors for the incursion, spread and persistence of the foot and mouth disease virus in Eastern Rwanda

BackgroundIdentification of risk factors is crucial in Foot-and-mouth disease (FMD) control especially in endemic countries. In Rwanda, almost all outbreaks of Foot-and-Mouth Disease Virus (FMDV) have started in Eastern Rwanda. Identifying the risk factors in this area will support government control efforts. This study was carried out to identify and map different risk factors for the incursion, spread and persistence of FMDV in Eastern Rwanda. Questionnaires were administered during farm visits to establish risk factors for FMD outbreaks. Descriptive statistical measures were determined and odds ratios were calculated to determine the effects of risk factors on the occurrence of FMD. Quantum Geographic Information System (QGIS) was used to produce thematic maps on the proportion of putative risk factors for FMD per village.ResultsBased on farmers’ perceptions, 85.31% (with p < 0.01) experienced more outbreaks during the major dry season, a finding consistent with other reports in other parts of the world. Univariate analysis revealed that mixed farming (OR = 1.501, p = 0.163, CI = 95%), and natural breeding method (OR = 1.626; p = 0.21, CI = 95%) were associated with the occurrence of FMD indicating that the two risk factors could be responsible for FMD outbreaks in the farms. The occurrence of FMD in the farms was found to be significantly associated with lack of vaccination of calves younger than 12 months in herds (OR = 0.707; p = 0.046, CI = 95%).ConclusionsThis is the first study to describe risk factors for persistence of FMDV in livestock systems in Rwanda. However, further studies are required to understand the role of transboundary animal movements and genotypic profiles of circulating FMDV in farming systems in Rwanda.

Chimpanzee feeding ecology and fallback food use in the montane forest of Nyungwe National Park, Rwanda.

Almost all primates experience seasonal fluctuations in the availability of key food sources. However, the degree to which this fluctuation impacts foraging behavior varies considerably. Eastern chimpanzees (Pan troglodytes schweinfurthii) in Nyungwe National Park, Rwanda, live in a montane forest environment characterized by lower primary productivity and resource diversity than low-elevation forests. Little is known about chimpanzee feeding ecology in montane forests, and research to date predominantly relies on indirect methods such as fecal analyses. This study is the first to use mostly observational data to examine how seasonal food availability impacts the feeding ecology of montane forest chimpanzees. We examine seasonal changes in chimpanzee diet and fallback foods (FBFs) using instantaneous scan samples and fecal analyses, supported by inspection of feeding remains. Chimpanzee fruit abundance peaked during the major dry season, with a consequent change in chimpanzee diet reflecting the abundance and diversity of key fruit species. Terrestrial herbaceous vegetation was consumed throughout the year and is defined as a "filler" FBF. In contrast to studies conducted in lower-elevation chimpanzee sites, figs (especially Ficus lutea) were preferred resources, flowers were consumed at seasonally high rates and the proportion of non-fig fruits in the diet were relatively low in the current study. These divergences likely result from the comparatively low environmental diversity and productivity in higher-elevation environments.

Possible Seasonal Pattern of Ebola Virus Disease in the Democratic Republic of the Congo

The Democratic Republic of the Congo has two seasons (dry and rain). However this allocation across the country is totally different in terms of length. First, in the north of Equator, the rainy seasons start from April until the end of June then from September to the end of October. The dry seasons start from the beginning of November until the end of March (called the major dry season) and the beginning of July until the end of August (the minor dry season). Second, in the south of Equator, the rhythm of seasons is exactly inversed. The rainy season starts from October to May and the dry season (mid-May until the end of September). Rains are almost constant along the year.

Study of aerosol optical properties at Kunming in southwest China and long-range transport of biomass burning aerosols from North Burma

Seasonal variation of aerosol optical properties and dominant aerosol types at Kunming (KM), an urban site in southwest China, is characterized. Substantial influences of the hygroscopic growth and long-range transport of biomass burning (BB) aerosols on aerosol optical properties at KM are revealed. These results are derived from a detailed analysis of (a) aerosol optical properties (e.g. aerosol optical depth (AOD), columnar water vapor (CWV), single scattering albedo (SSA) and size distribution) retrieved from sunphotometer measurements during March 2012–August 2013, (b) satellite AOD and active fire products, (c) the attenuated backscatter profiles from the space-born lidar, and (d) the back-trajectories. The mean AOD440nm and extinction Angstrom exponent (EAE440−870) at KM are 0.42±0.32 and 1.25±0.35, respectively. Seasonally, high AOD440nm (0.51±0.34), low EAE440−870 (1.06±0.34) and high CWV (4.25±0.97cm) during the wet season (May – October) contrast with their counterparts 0.17±0.11, 1.40±0.31 and 1.91±0.37cm during the major dry season (November–February) and 0.53±0.29, 1.39±0.19, and 2.66±0.44cm in the late dry season (March–April). These contrasts between wet and major dry season, together with the finding that the fine mode radius increases significantly with AOD during the wet season, suggest the importance of the aerosol hygroscopic growth in regulating the seasonal variation of aerosol properties. BB and Urban/Industrial (UI) aerosols are two major aerosol types. Back trajectory analysis shows that airflows on clean days during the major dry season are often from west of KM where the AOD is low. In contrast, air masses on polluted days are from west (in late dry season) and east (in wet season) of KM where the AOD is often large. BB air mass is found mostly originated from North Burma where BB aerosols are lifted upward to 5km and then subsequently transported to southwest China via prevailing westerly winds.

Genetic variation and relationship of traits related to drought tolerance in cocoa (Theobroma cacao L.) under shade and no-shade conditions in Ghana

Drought is the major abiotic stress limiting cocoa seedling survival during establishment. The level of genetic variation and relationship among traits related to drought tolerance were examined in a 6 × 6 incomplete diallel and 8 × 3 incomplete factorial mating designs for parents of diverse genetic groups. Thirty-eight families, 23 from the diallel and 15 from the factorial mating were evaluated in 2012/13 major dry season under shade and no-shade locations. Six-month old seedlings were planted in a randomized complete block design with two replications consisting of 24 plants per plot. Traits related to drought tolerance including stem growth, percentage survival, leaf chlorophyll content and plant vigour were monitored. Analysis of the 38 families showed highly significant (P ≤ 0.01) variation for families, replications, locations and location × family interaction for most of the traits. Preponderance of additive effects was manifested in terms of significant GCA when genetic analysis of the diallel was performed. Heritability was moderate to high (h 2b = 0.43–0.63) for broad sense and low to moderate (h 2n = 0.25–0.57) for narrow sense. Clones PA 13 and AMAZ 15/15 had positive GCA effects, whereas PA 150 and T60/887 had negative GCA effects for most traits. The highest genotypic correlations were between survival and vigour. Results from the study indicate that there is considerable genetic variation for traits related to drought tolerance in the available germplasm, and the families of some specific clones are able to survive droughts under typical field conditions in Ghana.

Effects of diking on the biological performance of the black mangrove (Avicennia germinans L.) in an Atlantic mangrove forest

The effects of diking on the photosynthetic rate, gross glucose production, biomass, and nutrient levels of the black mangrove Avicennia germinans L., were investigated during the major dry, the major wet and the intermediate season in completely diked mangrove areas, and compared to partially diked and non-diked biotopes. In the major dry and major wet seasons, the photosynthetic rate and gross glucose production were two to five times lower in the completely diked sites compared to the partially diked and non-diked habitats. The average dry weights of branches, flowers and leaves did not differ significantly between sites. The same held true for propagules from the major dry and major wet season. However, propagules from the transition period collected in the non-diked and partially diked biotopes yielded appreciable amounts of dry matter, while plants in the completely diked forests did not carry any propagules. No statistically significant differences were found among nutrient content in the leaves of plants from the different habitats. Our results suggest black mangrove growing in diked habitats may suffer a certain degree of environmental stress, which may affect important biological processes, such as photosynthesis, gross glucose production, and propagule formation.

Research on yam production, marketing and consumption of Nupe farmers of Niger State, central Nigeria

Questionnaire survey was conducted to obtain information from lowland rice cultivation based Nupe farmers in Niger State, central Nigeria regarding the current practices of yam production, marketing and consumption. In order to intensify yam production in Africa, scientists have developed various technologies to control growth cycle of yams for dry season production on wetlands. With appropriate natural environment and tradition of wetland utilization, the Nupe farmers in Niger State are targeted for introducing the new technologies to initiate dry season yam cultivation. Farmers can harvest ware yams during months when market prices of yam tubers are high, which would improve their incomes. Cassava as the current major dry season crop in the region may be replaced by yams which have far higher market and nutrition values. This research thus attempts to obtain basic information for future project planning. The findings suggest that, although in small scale, yams have been incorporated into the cropping system of Nupe farmers. Yams were mainly cultivated for self-consumption, so it was not market-oriented and resources inputs were limited. There were discrepancies between complex villages and upland villages in terms of production scale, variety, cultivating calendar and time pattern for sale and consumption. Key words: Yams, Nupe, farming system, inland valley utilization, off-season production.

Temporal dynamics of &lt;i&gt;Chaoborus larvae&lt;/i&gt; (Diptera : Chaoboridae) in the tropical ecosystem (lake Ayamé I ; Côte d’Ivoire).

Chaoborus larvae are voracious predators of zooplankton able to change their specific composition and size structure. Thus they appear as competitors of fish. They also represent food for planktophage fish. The temporal dynamics of Chaoborus larvae was studied (from january to october 1997) in the fishery of Bakro (5°33’N and 3°15’W) situated in lake Ayamé I (Côte d’Ivoire). Two peaks of density were observed : the most pronouced in March (end of the major dry season) with 747 ind./m2, and another, less pronouced in June (end of the major rainy season), with 280 ind./m2. Differences between densities may well be explained by the advent of the rainy season which leads to a decline in trophic resources (zooplankton) and exposes Chaoborus larvae to predation by fish.Key-words : Chaoborus larvae, Dynamics, lake Ayamé I, Côte d’Ivoire,West Africa.

INVESTIGATION OF STABLE ISOTOPE OF &lt;sup&gt;18&lt;/sup&gt;O AND &lt;sup&gt;2&lt;/sup&gt;H IN SHALLOW GROUNDWATER FROM KARAWANG AREA

Karawang area is well known as an agriculture area and 2% area is utilized for industries. Clean water demands increase due to developing industry development and population increasement. The origin of groundwater is necessary to keep the sustainability of water resources in this area. Stable isotopes such as 18O and 2H can be used as a parameter to trace the ground water origin. The methods used were Epstein-Mayeda and Zinc reduction for analysis 18O and 2H, respectively. Sampling period was conducted in major dry season in year 2002. The result showed that evaporation effect had influenced to the content of both isotopes in its shallow groundwater that caused a slope shift from its local meteoric line. The origin of its shallow groundwater was from rainwater infiltrating directly in less than 10 m altitude. Citarum River showed more depleted values in both isotopes compared to shallow groundwater and it indicated that its water might originate from spring at the altitude of 600 m. Keywords: oxygene-18, deuterium, groundwater, isotope

Factors Influemcing Commercial Charcoal Production in the West Mamprusi District of Ghana

Charcoal production is increasingly becoming an important trade in the northern regions of Ghana in spite of its implication for deforestation and natural resources depletion. In the West Mamprusi District of northern Ghana, charcoal production is a major dry season activity in many communities. This paper examines factors influencing the increasing rate of charcoal production in the district from 1980 to 2005. Research instruments employed were: purposive and simple random sampling, direct observation; transect walks, stump count, focus group discussion, key informant and structured interviews. The study reveals that local and national organizational structures exist that monitor the natural environment in the District; community members are aware of the environmental impact of their activities, and that charcoal production is a livelihood activity of the people in the District. Findings from the research revealed that charcoal production was a full time occupation for many females (i.e., 65%); major buyers were from urban towns in Northern and Upper East Regions; charcoal production was a major source of income and livelihood activities in the district and the work of the Forestry Commission's monitoring was effective in the forest-reserved areas. It concludes therefore that existing institutional structures have failed to implement regulations to control the effects. Ghana Journal of Development Studies Vol. 4 (21) 2007: pp. 33-48

Croissance en diamètre et caractérisation de la limite entre bois juvénile et bois adulte chez l’okoumé des plantations au Gabon

The fast-growing hardwood, okoume (Aucoumea klaineana Pierre), is a major forest species in Gabon and is used principally for making plywood, but research into the growth and quality of this wood is scanty. Trees from natural forests are favoured for production, yet little information exists on wood characteristics from plantation trees. Therefore, we carried out a dendrochronological study along with measurements of wood lon- gitudinal modulus of elasticity (EL), density (Dw), dimensional stability parameters (longitudinal, radial and tangential shrinkage and fibre saturation point) and fibre cell morphology to determine if these properties were related to age in trees from two plantations. We then used segmented regression analysis to define the limit (breakpoint) between juvenile (JW) and adult wood (AW). Using monthly precipitation data, we were able to determine that one growth ring is formed per year, composed of a large light coloured ring formed during the long rainy season and a thick, dark band formed during the major dry season. However, thinner bands, analogous to false rings, may also form during the short dry and short rainy seasons. Ring width decreases from the pith to the bark, and the breakpoint between JW and AW was at 19 years old when trees from both plantations were pooled together. No differences in Dw or radial and tangential shrinkage occurred with cambial age. EL increased significantly up to the cambial age of 12-14 years, after which the increase with age was only slight and no breakpoint between JW and AW was found. With regard to mean longitudinal shrinkage, AW was found to form after the age of 13 years but fibre cell length was significantly longer after the age of 14.5 and 20 years, depending on the plantation of origin. Therefore, the boundary between JW and AW in plantation grown okoume occurs between the ages of 13 and 20 years, depending on the characteristic examined.

Effect of nitrogen fertiliser applied to tef on the yield and N response of succeeding tef and durum wheat on a highland vertisol

A trial was conducted on an Ethiopian Vertisol from 1990 to 1995 to determine the residual effect of fertiliser N applied to tef (Eragrostis tef) following chickpea (Cicer arietinum) on the grain and straw yield, N content, and N uptake of succeeding crops of durum wheat (Triticum turgidum var. durum) and tef. Measures of N use efficiency across the interval 0 to 60 kg ha -1 of applied N contrasted between the two consecutive tef crops: tef following chickpea exhibited lower mean values for agronomic efficiency (AE), namely 11.7 vs 16.8 kg grain per kg applied N, and apparent recovery (AR), 37.8 vs. 66.4%, of N compared to the second consecutive tef crop. The magnitude and consistency of the beneficial carryover effect of N applied to tef on the succeeding tef and durum wheat crops was dramatic. The mean AE of 60 kg ha -1 of N applied to tef and wheat in the current season (using 0 N as the base) was 16.8 and 13.0 kg grain per kg fertiliser N, respectively; the mean AE of 60 kg N applied to tef in the previous season was 6.1 for both crop species. The results demonstrated a residual fertiliser N benefit equivalent to 36.3 and 46.9% of the response to current season N application for tef and durum wheat, respectively (i.e., across the interval from 0 to 60 kg fertiliser N ha -1 ). Across the same interval, the mean rates of apparent recovery of fertiliser N in tef and wheat were 66.4 and 65.4% for current season N application, and 25.7 and 36.1% for previous season N application. The carryover effects of applied fertiliser N on succeeding cereal crops on Vertisols in the Ethiopian highlands have several beneficial implications. Tef and wheat grain comprise the principal dietary components of the Ethiopian highland populace, while tef and wheat straw represent the major dry season feed source for Ethiopia=s livestock population. The current study demonstrates that the carryover benefit of applied fertiliser N enhanced the yields and N contents of the grain and straw of both wheat and tef, resulting in significant increases in total N uptake. Thus, both human and livestock populations in the Ethiopian highland Vertisol zones would benefit from an increase in dietary protein intake as well as an increase in the quantity of dietary staples. Any analysis of the profitability of fertiliser N response should reflect the multi-year benefit period.

Tree Phenology in a Tropical Montane Forest in Rwanda

The phenology of 568 trees of 49 species producing fleshy fruits was studied in a montane forest in Rwanda between January 1991 and January 1993. Fruiting peaked during the major wet season in March-May, but remained high during the major dry season in July-August. A period of reduced fruiting occurred in the beginning of each calendar year during the minor dry period. Leaf flushing peaked during the major dry season in July-August, whereas flowering peaked in the beginning of each calendar year. These observations were inconsistent with the general pattern predicted by an insolation-limitation hypothesis that community-wide flowering and leaf flushing in tropical forests should be closely related in time and that both phenophases reach their peaks during the period of the most intense insolation. When species were grouped by seed size, the large-seeded group displayed a greater temporal variation in fruit abundance (greater fruiting seasonality) than the small-seeded group. When species were examined individually, however, seed size was not related to either fruiting duration or within-species fruiting synchrony, two attributes determining the degree of fruiting seasonality of a species. Fruiting patterns manifested by a group thus could not be explained by attributes from species constituting the group. Different degrees of fruiting seasonality displayed by different seed-sized groups may be due to different degrees of within-group interspecific fruiting synchrony.

Patterns of fruit-fall phenology in the Lopé Reserve, Gabon

ABSTRACTPatterns of fruit production were monitored over a 1-year period, from June 1990–May 1991, by counting the numbers of freshly fallen ripe and unripe fruits on five 5-km line transects located within 35 km of one another, in lowland tropical rainforest in the Lopé Reserve, central Gabon. A total of 195 species of fruit were found, representing at least 45 taxonomic families. The majority of fruits came from trees. Fruits were assigned to one of six categories which reflected their dispersal syndrome: succulent, arillate, dehiscent, fleshy pods, wind-dispersed, others. About three-quarters of all species had fruits characteristic of those dispersed by animals. There was a marked seasonal pattern to fruit production, with both the diversity and number of ripe fruits available peaking in January, and lowest immediately before and during the major dry season. The only climatic variable that showed a significant statistical correlation with fruit production was insolation. Candidates for the role of keystone fruit species were identified from species which fruited during the major dry season, and patterns of fruit production compared with other areas.

Inter- and Intra-Specific Diet Overlap during Lean Times between Quelea erythrops and Bill Morphs of Pyrenestes ostrinus

Patterns of inter- and intra-specific resource use were examined between bill morphs of the African finch Pyrenestes ostrinus and Quelea erythrops. On my study area in south-central Cameroon diet overlap and breadth were examined after the major dry season when food was most limiting. Overlap values between P. ostrinus and O. erythrops declined with food supply, suggesting that interspecific competition occurred. Changes in the diets of small morphs which had bills more similar in size to Q. erythrops were primarily responsible for this decline. In contrast, diet overlap between morphs increased as food supply declined. Diet breath of small morphs also increased while crop size declined. Diet breadth and crop size in large morphs remained low throughout the study. These results, examined within the context of bill morphology, finch abundance, food supply and crop fullness are consistent with intraspecific competition occurring between morphs. Additionally, small morph and Q. erythrops exploitation of scarce supplies of soft seeds may be responsible for large morphs specializing on hard seeds during the non-breeding season

Resource Use by Bill Morphs of An African Finch: Evidence for Intraspecific Competition

The African estrildid finch Pyrenestes ostrinus exhibits a polymorphism in bill size that is not related to sex. This paper examines the feeding ecology, sessonal changes in abundance, and diet overlap of the two bill morphs on a study are in south—central Cameroon. The morphs fed on two major sedge species, hard and soft. The diets of the small— and large—billed morphs were influenced by their feeding efficiencies on the sedges and seed abundance. When both major sedges were abundant, diet overlap between morphs was high, but overlap declined during the major dry season when overall food abundance was low. During the dry season, large—billed morphs specialized on the hard—seeded sedge species while small—billed morphs broadened their diet to include other foods. This pattern of resource use is consistent with increased intraspecific compeition for food and similar to patterns of resource use between distinct species during food—lean times. A model for the evolution of the polymorphism is presented.

Coadaptation entre rythmes de fructification et frugivorie en forêt tropicale humide du Gabon : mythe ou réalité ?

Fruiting patterns were studied for a year in lowland evergreen forest at Makokou, Gabon. Temporal patterns of fruiting were analysed according to vegetative life-form of the parent, morphological fruit type, seed dispersal mode and seed weight. In addition, fruiting cycles of 109 individuals of 13 species were monitored for two years. The results are summarized as follows : 1. Fruiting at Makokou is seasonal : fruiting peaks occur during the major rainy season and minor dry season, while the major dry season and minor rainy season are periods of fruit scarcity. A comparison with data from earlier years shows that there can be large inter-year variations in fruiting patterns. 2. There are some differences in the amplitude of fruiting seasonality depending on the parental life-form : as a group, medium-sized trees are the most strongly seasonal, emergent trees are less so. The monthly patterns of numbers individuals fruiting also differ between life-forms, as does the timing of fruiting peaks. 3. There is no clear seasonal difference in the amplitude of fruiting seasonality for different morphological types of fruits, or seed dispersal modes. Moreover, the yearly maxima in numbers of fruiting species are the same for anemochores, zoochores and autochores ; however, seasonal patterns differ depending on the fruit type (dehiscent vs indehiscent ; dull-colored fleshy fruit vs brightly-colored fleshy fruit). 4. There is no clear difference in amplitude of seasonality for fruits with different seed weights. 5. Analysis by species shows that regardless of dispersal mode, there is a complete gradient from species with strong seasonality, either annually uni-modal, or bi-modal, to those with weak seasonality and fruit production throughout most of the year. 6. Monitoring individual trees showed that among zoochorous species there can be annual, biennal or multiannual cycles, with regular, irregular or without obvious periodicity, and with fruiting synchrony or asynchrony among individuals of the same species. These results are compared to those reported for other tropical rainforests. Although we showed in a simultaneous study that there are broad suites of morphological fruit characters associated with broad categories of consumers (Gautier-Hion and al., 1985), the results presented here do not suggest an evo¬ lutionary influence of consumers on the timing of fruiting. While it is possible by selecting appropriate species subsets to suggest correlations demonstrating the influence of dispersal agents on phenology, it is likewise possible by choo¬ sing different subsets to formulate hypotheses about fruiting phenology in which coadaptation with dispersers does not play any role.