Deficit irrigation (DI) has been implemented in arid regions to improve water productivity while maintaining or increasing crop yield. In this study, we carried out a global scale meta-analysis to (1) quantify the response ratios of grain yield (GY), actual crop evapotranspiration (ETc act) and water productivity (WP) under DI stress. Then, we (2) examined the effects of nitrogen (N), phosphorus (P) and potassium (K) fertilizer rates, climate, soil texture, DI application mode, and maize growing cycle on GY, ETc act and WP. A total of 1192 observations retrieved from 167 studies were used to estimate the effect size and generate forest plots for each factor at three different growth stages. The response ratio (RR) of maize GY was higher for short-cycle varieties (RR, −0.14), in semi-arid climates (RR, −0.25) and under irrigation amount reduction (RR, −0.21). Maize ETc act was higher for long and medium cycle varieties (RR, −0.22), for medium-textured soils (RR, −0.14) and drier climates. The WP improved by 9% on heavy soils compared to both light and medium soils, indicating that heavy soils are more suitable for growing maize under DI. This study highlights that high DI stress was often applied with low nitrogen rates to limit reciprocal effect on yield loss. The application of DI stress before the reproductive stage induced an adaptation strategy that limits maize yield loss and improves WP. Thus, the application of DI stress should start earlier at the vegetative stage to be more beneficial to maize. Furthermore, DI stress should target early-maturing maize varieties to achieve higher crop WP. The findings imply that DI stress could be a promising strategy for water management in maize cropping systems while considering appropriate soil, growing stages, varieties and climate.
Background: Type 2 diabetes mellitus (T2DM) is becoming one of the leading causes of morbidity and mortality worldwide, including among Africans. Knowledge of the association between traditional risk factors and both diabetes and pre-diabetes, and whether these differ by age and sex, is important for designing targeted interventions. However, little is known about these associations for African populations. Methods: The study used data from WHO STEPS surveys, comprising 15,520 participants (6,774 men and 8,746 women) aged 25-64 years, from 5 different West African countries, namely Burkina Faso (4,711), Benin (3,816), Mali (1,772), Liberia (2,594), and Ghana (2,662). T-test and chi-square tests were used to compare differences in the prevalence of traditional risk factors for both sexes. Multinomial logistic regression was conducted to ascertain the relative risks (RR) and 95% confidence intervals (CI) for both T2DM and impaired fasting glucose (IFG) relating to each risk factor, including obesity [defined by BMI, waist circumference (WC), waist-to-hip ratio (WHR), and waist-to-height ratio (WHtR)], high blood pressure (HBP), fruit and vegetable consumption, physical inactivity, alcohol consumption, and smoking. Models for each of these traditional risk factors and interactions with age and sex were fitted. Results: Factors associated with T2DM and IFG were age, obesity [defined by BMI, WC, WHtR, and WHR], HBP, smoking, physical inactivity, and fruit and vegetable consumption (p < 0.05). Analysis of interaction effects showed few significant differences in associations between risk factors and T2DM according to age or sex. Significant interaction with age was observed for HBP*age and T2DM [RR; 1.20, 95% CI: (1.01, 1.42)) (p = 0.04)], WHtR*age and T2DM [RR; 1.23, 95% CI: (1.06, 1.44) (p = 0.007)] and WHR*age and IFG [RR: 0.79, 95% CI: (0.67, 0.94) (p = 0.006)]. Some interactions with age and sex were observed for the association of alcohol consumption and both IFG and T2DM, but no clear patterns were observed. Conclusion: The study found that with very few exceptions, associations between traditional risk factors examined and both IFG and T2DM did not vary by age or sex among the West African population. Policies and public health intervention strategies for the prevention of T2DM and IFG should target adults of any age or sex in West Africa.
Background: Occupational stress is a psychosocial risk in the workplace. Working conditions in industrial settings may lead to occupational stress. In Benin, however, there is little epidemiological data on occupational stress in industrial settings. We aimed to determine the prevalence and factors associated with occupational stress in industrial settings in Benin in 2019. Methods: This was a prospective, cross-sectional study conducted from January 31 to April 11, 2019, among 15 cotton ginning plants. Sampling was exhaustive for permanent workers and stratified in clusters by shift for occasional cotton gin workers. Data were collected through Karasek and Siegrist questionnaires. Data analysis was performed using R software. Binary multivariable logistic regression was performed. The significance level was p < 0.05. Results: Of 1883 workers included, 90.8% were male. The median age was 38 years (IQR: 28 years to 49 years). The prevalence of occupational stress was 77.7% (95% CI: 75.8-79.6). Psychological demand was high in 93.0% of workers and 83.9% had low decision latitude. Among the workers, 16.3% had low social support and 89.9% had a low recognition score at work. Factors associated with occupational stress were: being an occasional vs. permanent worker (aOR 6.43, 95% CI 4.18 to 9.88); age less than 38 years (aOR 0.55, 95% CI 0.41 to 0.76); high intensity physical activity at work (aOR 1.33, 95% CI 1.03 to 1.73); working in production vs. administration (aOR 1.59, 95% CI 1.03 to 2.45); spending fewer than 4 years at the current work location (aOR 1.60, 95% CI 1.05 to 2.44); and scoring low for recognition at work (aOR 1.53, 95% CI 1.04 to 2.23). Noise exposure and being a shift worker were significant in univariable analysis, but not multivariable analysis. Conclusion: Occupational stress is very common among workers in industrial settings. The implementation and evaluation of preventive measures against these risk factors is necessary.
Despite the ubiquity of nonlinear functional relationships in nature we tend to characterize mechanisms in science using more tractable linear functions. In demographic modeling, transfer function analysis is used to calculate the nonlinear response of population growth rate to a theoretical perturbation of one or more matrix elements. This elegant approach is not yet popular in ecology. Inconveniently, using transfer function without care can produce erroneous results without warning. We used a large matrix projection model database to explore the potential pitfalls to be avoided in using transfer function analysis. We asked a fundamental population control question, what matrix element perturbation would be needed to reach a minimum goal of replacement population growth? We then tracked instances in which transfer function yields erroneous output and explored these cases in detail to measure how frequently it occurs. We developed a phylogenetically‐corrected mixed effects logistic regression model in a Bayesian framework to test the effect of species traits and the identity of matrix elements on the probability that transfer function yields errors. We found in 16% of cases the transfer function yielded erroneous outcomes. These errors were more likely when perturbing demographic stasis and also for shrubs more than any other life form. Errors in transfer function analysis were often due to perturbing matrix elements beyond their biological limits, even when this is still mathematically correct. To use transfer function analysis properly in demographic modeling and avoid erroneous results, input must be carefully selected to include only a biologically admissible set of perturbations. In a size‐ age‐ or stage‐structured population, how the population growth rate (λ) responds to a change (δ) in a single demographic rate is often nonlinear. Due to biological and/or mathematical boundaries inherent in a species' biology and its projection matrix, reaching a target growth rate may sometimes be out of reach. The mathematical behavior of a perturbed matrix may be unexpected for many biologists. In this brief article, we map the underlying relationships between all matrix eigenvalues (λ) and changes (δ) to matrix entries to reveal potential pitfalls when using the transfer function to calculate future population growth with hypothetical changes in demographic rates.
An in-situ study combined with an integrated biomarker response was used to evaluate the impact of agricultural effluents in the physiological responses of Nile tilapia reared in cages and enclosures of water reservoirs in North Benin. Fish were distributed in fish farming systems at two sites: Songhai located outside the cotton basin and Batran located in the most productive commune. They were sampled for blood and organs before (BST), during (DST) and after (AST) pesticide treatment. Pesticide residues were analysed in water, sediments and fish muscles. Several biomarkers were investigated related to the immune (peroxidase, lysozyme and complement activities, superoxide anion production) and reproductive (sex steroids and vitellogenin levels) responses as well as neurotoxicity (cholinesterase activity) and tissue alterations. Biomarkers were assessed and analysed via the integrated biomarker response (IBR). The results showed that Batran water reservoir was a more harmful ecosystem for fish than Songhai one, especially by depressing some immune and reproductive functions in relation to a higher-level of pesticide contamination. They also demonstrated that the contact of fish to sediments in enclosures aggravated the pesticide burden on fish. Therefore, using males as bioindicators would improve the sensitivity of the used biomarkers since males seemed more affected than females especially due to pesticide estrogenic induction impacting their reproductive system.
In this paper, we proposed an analytical framework based on the institutional theory to analyze the effect of institutional context on the impact of entrepreneurship education (EE). The influence of institutional environment was captured through three variables, namely perceived government support, perceived cultural norms, and social legitimacy of entrepreneurship. Based on a sample of 788 respondents from two African countries, our results show that beyond EE, institutional context is equally a determining factor of students’ entrepreneurial intention. Thus, a favorable institutional environment increases the students’ entrepreneurial intention. Our results also reveal that the positive effect of EE is higher when government policies are conducive to entrepreneurship development while it is lower when socio-cultural context (cultural norms, social legitimacy) is conducive to entrepreneurship. Thus, this study shows that informal institutions have a contingency effect while formal institutions play a complementary role in the impact of EE on students’ entrepreneurial intention.
Background: Polycystic ovary syndrome (PCOS) is a complex, chronic condition characterized by anovulation, polycystic ovarian morphology and hyperandrogenism that requires lifelong management. To reduce the risk of comorbidity and to manage symptoms, lifestyle management and pharmaceuticals such as oral contraceptives are the most common forms of treatment and should be tailored to the individual patient. The literature to date has shown PCOS patients to experience widespread dissatisfaction with the amount and quality of information they receive from providers, along with lower levels of trust in physicians. Little is known about the lived experiences of women managing PCOS in Canada, across age groups. Methods: In-depth remote interviews explored women's lived experiences managing PCOS and the barriers and facilitators they encountered in their management journeys. Data were analyzed using thematic analysis and interpretive description methodology. Results: Twenty-five in-depth, telephone interviews conducted with participants (aged 18-63 y) across Canada revealed participants lacking sufficient information and guidance from physicians, especially in primary care. Areas in need of more guidance included lifestyle management and mental health. Lack of empathy and weight bias among physicians were also perceived by participants. Older participants received little guidance on treatment options postmenopause. Loss of trust and withdrawal from seeking medical care were prominent themes, along with greater self-reliance on self-management, including self-educating and self-experimenting with treatments. Conclusions: Most women in this study were frustrated with the level of involvement and information provision from their doctors. Key recommendations are identified for the provision of care to younger and older patients with PCOS. Improved education for physicians may be needed to improve the quality of healthcare provision for PCOS.
The Alibori River, which flows through Benin’s cotton crop regions, receives surface water from much of the cultivated land that is situated along its banks. Chemical pollution in surface runoff from this land use threatens the ecological quality of the river. This study aimed to characterise the ecological status of the Alibori River under such agricultural pressures using biological indices and macroinvertebrate metrics. Water and macroinvertebrate samples were taken monthly from fifteen sites along the river between June 2015 and May 2016. The measured physico-chemical parameters and biological indices were subjected to descriptive statistics, bivariate correlations and partial least squares regression (PLSR). Taxonomic richness decreased from the upstream to the downstream reaches of the river. Sampling sites with high mineral content and organic load were home to more pollutiontolerant taxa, such as Chironomidae and Oligochaeta, with a high abundance of Thiaridae. Diversity indices reveal an unbalanced community and macroinvertebrate distribution characterised by the development of opportunistic taxa such as the gastropod Melanoides tuberculata. Decreases in taxonomic composition and community organisation between the upstream and downstream reaches of the river appear to be linked to less stable environmental conditions at the downstream sampling sites, and were compounded with a gradual increase in stress for organisms from the upper to lower reaches of the river. The composition, distribution and diversity characteristics of taxa collected is an indication that the ecological status of the Alibori River is under pressure, as a result of the agricultural activities along its banks. Keywords: biomonitoring, disturbances, freshwater, physico-chemical parameters
The management of pastoral mobility is a stakeholder-centered approach for the integration of resource conservation and agricultural development. This management of space and its resources is the responsibility of a group of actors who are responsible for resolving conflicts of interest. This study aimed at analyzing the influence of transhumance stakeholders in the municipality of Djidja in southern Benin thanks to semi-structured interviews, which were conducted with 300 transhumance actors. The Likert scale (1 to 5) was used to assess the levels of influence and focus groups were conducted. The results obtained showed that several stakeholders were involved in transhumance with diverse interests, backgrounds, knowledge and power (p < 0.05). The majority of farmers (72%) blame transhumant herders whose practices are source of multiple conflicts. The analysis indicated a strong influence with highly significant differences (p < 0.001) in the management of transhumance by four stakeholders including the communal transhumance committee, the association of herders, the Garso (Scout and intermediary for transhumant herders) and the transhumant herder. This research demonstrates how the systematic analysis of the activities carried out by the actors, the interconnected activities between them and their relationships can offer insights for a better coordination of transhumance. For management to become reality, it is important building partnership between the various stakeholders linked by transhumance in southern Benin.
This research focuses on Kigelia africana in Benin where it is widely used in traditional medicine but receives little attention from researchers. In addition, this species has recently been recorded as threatened in the country. The aim was to gather ethnobotanical knowledge using a printed semi-structured questionnaire to collect data from herbal medicine traders, randomly selected, through a face-to-face discussion. The survey was carried out from January to March 2020. Among 36 questioned herbal traders, 36% of respondents obtained parts of K. africana by purchase in their own markets and by travelling far (3–10 km covered). The same proportion travel very far before buying parts (more than 10 km covered). None mentioned harvesting parts from wild populations. A high proportion of informants (63%) sold fruits and stem bark whereas a relatively low proportion of them (37%) sold fruits, stem bark, and leaves. The stem bark was recorded as most in demand followed by fruits. Respondents mostly confirmed the species scarcity. This species was used to treat 13 diseases and disorders. The stem bark was the most cited in the management of stomach infections and gynecological disorders. Fruits were mainly used in magic rituals and the treatment of stomach infections. Five preparations were recorded whither 54% of traders mentioned bark decoctions and 27% highlighted infusion of fruits in water. Overall, Kigelia africana is an important plant in Beninese ethnomedicine and the harvest and trade of its different parts represent major threats. Therefore, urgent conservation tools and actions are needed. Keywords: Kigelia africana; ethnobotanical knowledge; Benin; herbal medicine traders; infections
Studying body development in animals is an essential component for improving their production. The objective of this study was to study body measurements with regard to sex and age in Borgou cattle breed reared at the Okpara Breeding Farm. Data were collected on 244 animals (including 114 males and 120 females) distributed in 0-6, 6-12, 12-24, 24-36, 36-48 and >48 months classes. Data were compared using Student t-test in R software. The results showed that age had a very significant effect (p<0.001) on all measurements. For age groups 0-6, 6-12, 12-24 and >48 months, males presented higher values for body measurements than females on the measurements (p<0.05). However, for 24-36 months, the values of measurements such as Height at the withers, Height at the sacrum, Distance from the Head until the Ischium, Body length, Head length, Pelvic width, Head width, and Chest Perimeter were higher in females (p<0.05). Over 48 months, only the values obtained for Pelvic width were significantly higher in females (p<0.001). The results of this study can be used in selection and genetic improvement processes of Borgou cattle to improve the contribution of cattle farming to agricultural GDP in Benin.
Background Data on the prevalence of sleep-disordered breathing (SDB) in the African general population are scarce, and a better understanding is urgently needed. Our study aimed to objectively determine the prevalence of, and factors associated with, SDB in a large sample in Benin, west Africa. Methods In the Benin Society and Sleep (BeSAS) cross-sectional study, participants aged 25 years and older were recruited from both urban and rural areas. Rural participants were recruited from Tanve, a village located 200 km north of Cotonou, and urban participants were recruited from Cotonou. The participants underwent respiratory polygraphy at home using a type-3 device that measures airflow through a nasal pressure sensor, respiratory effort (thoracic movement), and pulse oximetry. Clinical and morphometric data were also collected. SDB severity categories were defined according to the apnoea–hypopnoea index (AHI), with mild-to-severe SDB (AHI ≥5/h), moderate-to-severe SDB (AHI ≥15/h), and severe SDB (AHI ≥30/h). Findings The study was completed from April 4, 2018 to Jan 15, 2021. Of 2909 participants recruited in the BeSAS study, 2168 (74·5%) underwent respiratory polygraphy. For the 1810 participants with complete polygraphic data (mean age 46 years, SD 15; 1163 [64·2%] women), the prevalence of mild-to-severe SDB (AHI ≥5/h) was 43·2% (95% CI 40·9–45·5), of moderate-to-severe SDB (AHI ≥15/h) was 11·6% (10·2–13·1), and of severe SDB (AHI ≥30/h) was 2·7% (2·0–3·5). Factors independently associated with SDB were advanced age, male sex, large neck circumference, abdominal obesity, overweight or obesity, and snoring. After multivariable adjustment, severe SDB was independently associated with hypertension in women (odds ratio 3·99, 95% CI 1·04–15·33; ptrend=0·044), but not in men (odds ratio 0·67, 0·22–2·05; Ptrend=0·63). Interpretation The BeSAS study provides the first large-scale objective evaluation of SDB prevalence and associated factors in Africa. The high prevalence of SDB identified should stimulate the development of public health policies to prevent and treat this condition in African countries. Funding Ligue Pulmonaire Vaudoise, Switzerland.
Objectives There is a dearth of evidence on inequalities in vitamin A supplementation in Ethiopia. The goal of this study was to assess the magnitude and overtime changes of inequalities in vitamin A supplementation among children aged 6–59 months in Ethiopia. Methods We extracted data from four waves of the Ethiopia Demographic and Health Surveys (2000, 2005, 2011, and 2016). The analysis was carried out using the 2019 updated World Health Organization’s Health Equity Assessment Toolkit software that facilitates the use of stored data from World Health Organization’s Health Equity Monitor Database. We conducted analysis of inequality in vitamin A supplementation by five equity stratifiers: household economic status, educational status, place of residence, child’s sex, and subnational region. Four summary measures—population attributable fraction, ratio, difference, and population attributable risk—were assessed. We computed 95% uncertainty intervals for each point estimate to ascertain statistical significance of the observed vitamin A supplementation inequalities and overtime disparities. Results The findings suggest marked absolute and relative pro-rich (population attributable fraction = 29.51, 95% uncertainty interval; 25.49–33.53, population attributable risk = 13.18, 95% uncertainty intervals; 11.38–14.98) and pro-urban (difference = 16.55, 95% uncertainty intervals; 11.23–21.87, population attributable fraction = 32.95, 95% uncertainty intervals; 32.12–33.78) inequalities. In addition, we found education-related (population attributable risk = 18.95, 95% uncertainty intervals; 18.22–19.67, ratio = 1.54, 95% uncertainty intervals; 1.37–1.71), and subnational regional (difference = 38.56, 95% uncertainty intervals; 29.57–47.54, ratio = 2.10, 95% uncertainty intervals; 1.66–2.54) inequalities that favored children from educated subgroups and those living in some regions such as Tigray. However, no sex-based inequalities were observed. While constant pattern was observed in subnational regional disparities, mixed but increasing patterns of socioeconomic and urban–rural inequalities were observed in the most recent surveys (2011–2016). Conclusion In this study, we found extensive socioeconomic and geographic-based disparities that favored children from advantaged subgroups such as those whose mothers were educated, lived in the richest/richer households, resided in urban areas, and from regions like Tigray. Government policies and programs should prioritize underprivileged subpopulations and empower women as a means to increase national coverage and achieve universal accessibility of vitamin A supplementation.
Pyrethroid resistance is widespread in sub-Saharan Africa. The objective of this study was to assess the insecticide resistance intensity in Anopheles gambiae s.l. (Diptera: Culicidae) in four districts of Benin in order to better understand how pyrethroid-only nets are likely to be effective. Thus, adult females of An. gambiae s.l., reared from field-collected larvae were used for assessing resistance intensity to permethrin and deltamethrin. They were tested at 1×, 5×, and 10× the diagnostic dose, using both WHO susceptibility tube testing and CDC bottle bioassays. Identification of molecular species, as well as of L1014F Kdr and Ace-1R mutations was performed using the PCR. The level of expression of biochemical enzymes was also evaluated. Overall, moderate to high resistance intensity to permethrin and deltamethrin was observed, irrespective of the testing method. While the L1014F Kdr frequency was high (>75%), Ace-1R was low (≤6%) in An. gambiaes.s. and Anopheles coluzzii, the two predominant species [52% (95% CI: 44.8–59.1) and 45% (95% CI: 38.0–52.2), respectively]. Anopheles arabiensis was found at very low frequency (3%, 95%CI: 1.1–6.4). For Biochemical analyses, α and β-esterases were over-expressed in all four districts, while mixed-function oxidases (MFOs) were over-expressed in only one. Overall, the two testing methods led to comparable conclusions, though there were a few inconsistencies between them. The moderate-high resistance intensity observed in the study area suggests that dual active-ingredient (AI) long-lasting insecticidal nets (LLINs) may provide better control of insecticide-resistant mosquitoes.
An assessment of hydropower potential at the watershed scale was conducted at the White Bandama Watershed (WBW) in Côte d'Ivoire (West Africa). The method used involves the application of a hydrological model [Soil and Water Assessment Tool (SWAT)] coupled with a Quantum Geographic Information System (QGIS), denoted as QSWAT, to assess the water resource availability and hydropower potential of streams and determine potential hydropower sites for future hydropower development in the watershed. Geospatial data about the topography, soil types, land use/land cover, weather, and discharge were considered in hydrological and hydro-geomorphological characterization of the watershed. Streamflow and climate data-enabled model operation and simulation of the hydrology of the watershed. The model performance and robustness were confirmed with the p-factor, r-factor , coefficient of determination R ² , and Nash–Sutcliffe (NS) efficiency coefficient. The hydropower potential of streams was evaluated by considering the simulated streamflow and water head. A total of 22 future hydropower sites was identified, geolocated, and classified with an estimated total production capacity of 538.56 MW.
Achievement of sustainable agricultural development and national food security in Africa is dependent on several factors, including productivity in the livestock production sub-sector. This study surveyed farmers’ perceptions on provision of extension services relating to livestock production in Burkina Faso, Mali, and Benin. A structured questionnaire comprising dichotomous, multiple-choice, and open-ended questions was used to survey a total of 1560 farmers in Burkina Faso, 345 in Mali, and 480 in Benin. Most farmers surveyed pursued integrated crop and livestock production, but more frequently in Burkina Faso (91%) than in Mali and Benin (66%). Around one-third (36%) of the respondents in Burkina Faso had access to livestock extension services, while the corresponding figure in Mali and Benin was 54% and 69%, respectively (p < 0.01). Moreover, 71% of respondents in Mali, 73% in Burkina Faso, and 84% in Benin reported significantly (p < 0.05) fewer extension activities for livestock compared with crop production. Thus, livestock production seems to be given low priority in agricultural extension interventions. We recommend that future diffusion of technological packages should be more holistic, considering the major concerns of the specific environment and the socio-cultural traditions of both livestock and crop producers.
The center-periphery hypothesis predicts that species are most abundant at the center of their distribution range. Differential herbivory rates between center and periphery populations can explain this variation in species abundance. However, if the geographic center of a species distribution coincides with its ecological optimum, the resource availability hypothesis predicts higher herbivory rates and tolerances at the center compared to the periphery. Biogeographical studies on herbivory have treated these two mechanisms separately, limiting our mechanistic understanding of the role of herbivory in shaping species range limits. We analyzed the role of resource avail- ability on herbivory variation from center to periphery using data collected across the distribution of Thunberbia atacorensis, a range-limited species of West Africa. We used two types of distances: geographic distance (the distance from each plot to the geographic center of all populations) and climatic distance (the distance from each plot to the preferendum of the species). We found no increase in herbivory toward the periphery of the climatic and geographic ranges. However, herbivory rates increased with soil nitrogen. Soil nitrogen decreased from the center to the periphery of the cli- matic range. Phylogenetic diversity and competition from surrounding plants did not affect herbivory rates. Our study provides insights into how nutrient limitation can shape species center-periphery distribution by altering spatial variation in herbivory rates.
Improving agricultural production in response to the increasing food demand remains a major challenge in agroecology. The world has made significant efforts to meet this issue by developing several cultivation techniques, such as the use of chemical fertilizers and arable land conversion into agricultural land. However, most of these techniques have caused a significant loss of biodiversity and ecosystems services. Recent data suggest that biological conservation within and around agroforestry systems are potential solutions that can both reduce biodiversity loss and guarantee crop production. This logic is based on the hypothesis that increasing plant diversity in and around agricultural systems can limit the pest attack rate and increase crop yield. We tested this hypothesis using structural equation modeling on empirical data collected in agroforestry systems around the Pendjari biosphere reserve in West Africa. We measured crop diversity, crop yield, arthropod pest diversity, abundance, the rate of crop herbivory, and the diversity of plants in surrounding natural vegetation in 32 permanent plots. We estimated arthropod diversity and abundance using pitfall traps. We found a direct positive effect for plant diversity and a direct negative effect of arthropod herbivory on crop yield. The diversity of plants in surrounding natural vegetation had a direct positive effect on arthropod pest diversity but a marginal negative direct effect on the rate of crop herbivory. We found no significant direct or indirect effect for crop diversity. Our findings underline the important role of biodiversity conservation in agricultural production improvement. We suggest that the conservation of plant diversity around agroforestry systems may be an effective option to control herbivory damage. Its combination with other pest control techniques may further limit crop depredation and ensure the long-term conservation of wildlife.
Un inventaire des parasites digestifs de la grenouille comestible Hoplobatrachus occipitalis a été réalisé au Bénin. Au total, 135 spécimens ont été pêchés dans les bassins hydrographiques des fleuves Mono, Ouémé et Niger, et examinés au laboratoire. Les résultats montrent que 78,52% des sujets ont au moins un œuf par gramme de fèces. Les pourcentages d’individus infestés sont de 91,11%, 77,77% et 66,67%, respectivement pour le Mono, l’Ouémé et le Niger (P?0,05). Les nématodes (Oxyuris sp., Œsophagostomum sp. et Heterakis sp.) et les coccidies (Eimeria sp.) sont identifiés. Les fréquences d’infestations singulières ou croisées des sujets sont les suivantes : Eimeria sp. (25,93%), Eimeria sp. et Oxyuris sp. (25,19%), Oxyuris sp. (20,00%), Eimeria sp. et Heterakis sp. (2,96%), Eimeria sp. et Œsophagostomum sp. (2,22%), Œsophagostomum sp. (1,48%) puis Heterakis sp. et Oxyuris sp. (0,74%). Un taux d’infestation de 20,74% de grenouilles moyennement infestés contre 54,81% fortement infestés est obtenu avec un niveau d’infestation variant de façon significative d’un bassin à un autre (P?0,001). Les taux d’infestation sont respectivement de 80,43%, 68,89% et 86,36% dans le côlon, l’intestin grêle et ces deux organes pris simultanément. La proportion des sujets adultes infestés (87,50%) est significativement supérieure à celle des juvéniles (61,70%) (P?0,05). Mots clés: Grenouille, Hoplobatrachus occipitalis, comestible, parasites
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