Farmer Choice of Sorghum Varieties in Southern Mali

In southern Mali and throughout the semiarid tropics, small-scale family farmers are faced with the challenge of producing adequate harvests in difficult biophysical and socioeconomic environments. Professional plant breeders have had much difficulty developing modern varieties that outperform farmers’ traditional varieties in these environments, in part because of an incomplete understanding of why farmers choose the varieties they grow. Improved understanding of farmers’ varietal choices can contribute to collaboration between farmers and formal plant breeders. Based on a 15-month field study in Dissan, Mali, we examine farmer's choices among their traditional sorghum varieties in terms of one or more than one variety, and short-cycle or long-cycle varieties, and the interaction between these two choices. Results support our general hypothesis that farmers choose varieties to optimize outputs in the face of variation in the growing environment and in human managed inputs such as labor and tools.     

Low infectivity of Plasmodium falciparum gametocytes to Anopheles gambiae following treatment with sulfadoxine-pyrimethamine in Mali

Sulfadoxine-pyrimethamine (SP) treatment increases the rate of gametocyte carriage and selects SP resistance-conferring mutations in Plasmodium falciparum dihydrofolate reductase (DHFR) and dihydropteroate synthase (DHPS), raising concerns of increased malaria transmission and spread of drug resistance. In a setting in Mali where SP was highly efficacious, we measured the prevalence of DHFR and DHPS mutations in P. falciparum infections with microscopy-detected gametocytes following SP treatment, and used direct feeding to assess infectivity to Anopheles gambiae sensu lato. Children and young adults presenting with uncomplicated malaria were treated with SP or chloroquine and followed for 28 days. Gametocyte carriage peaked at 67% 1 week after treatment with a single dose of SP. Those post-SP gametocytes carried significantly more DHFR and DHPS mutations than pre-treatment asexual parasites from the same population. Only 0.5% of 1728 mosquitoes fed on SP-treated gametocyte carriers developed oocysts, while 11% of 198 mosquitoes fed on chloroquine-treated gametocyte carriers were positive for oocysts. This study shows that in an area of high SP efficacy, although SP treatment sharply increased gametocyte carriage, the infectiousness of these gametocytes to the vector may be very low. Accurate and robust methods for measuring infectivity are needed to guide malaria control interventions that affect transmission.     

Natural Resource Management, Paradigm Shifts, and the Decentralization Reform in Mali

The mainstream view in natural resource management in African drylands has been that local people are responsible for natural resource degradation. Today, alternative views or new paradigms are emerging in several fields. These new paradigms, which support decentralization of natural resource management, are discussed in relation to the ongoing decentralization process in Mali. During the colonial period, heavily centralized governments were installed in all the French colonies. This structure was maintained by Malian governments after independence. However, following the recent transition to democracy, a decentralizing reform is being implemented. It is presently not clear whether these reforms will lead to mere deconcentration, involving the redistribution of administrative responsibilities within the central government, or whether Mali is heading toward real decentralization, devolving decision making powers to local communities. The gestion de terroir approach, which may be a useful tool in achieving decentralization in farming communities, would, in pastoral areas, cause more damage than benefit.     

Distribution spatio-temporelle de la faune de phlébotomes en zones urbaine et périurbaine de Bamako,Mali

Au Mali la leishmaniose cutanée (LC) est bien décrite en milieu rural, mais sa transmission n’est pas encore établie en milieu urbain. L’objectif de l’étude était de décrire la faune phlébotomienne à Bamako et dans ses environs. Les pièges CDC et adhésifs servaient à collecter les phlébotomes en 2011 et 2012 à Bamako. Les pièges étaient placés dans le district de Bamako répartis en 30 zones (200 m × 200 m) à l’aide des images de satellite SPOT-5. La délimitation des zones était basée sur les facteurs écologiques (relief, hydrographie, couverture végétale) et anthropologiques (nature des maisons, dépôts d’ordure). Les pièges étaient placés en 2011 à Sotuba, zone périurbaine, puis à Donéguébougou et Banambani, deux villages environnants de Bamako. Au total 122 phlébotomes étaient collectés 27 (22,13 %) à Banambani, 12 (9,83 %) à Donéguébougou, 2 (1,63 %) à Sotuba et 81 (66,39 %) à Bamako. La densité des phlébotomes en novembre était plus élevée, avec 48 spécimens capturés (39,3 %), que celle d’avril, mai et décembre (p ≥ 0,001). A Bamako, les zones 6 et 28 étaient associées aux densités les plus élevées de phlébotomes respectivement 32 (26,22 %) et 23 (18,85 %) (p ≤ 0,005). Les résultats suggèrent que le genre Phlebotomus n’était pas présent à Bamako, et que la densité des vecteurs variait en fonction des zones et des mois.     

Development of Orius vicinus (Ribaut) (Heteroptera: Anthocoridae) on Different Prey

The survival, development and adult size of Orius vicinus were studied on five prey species, the mites Aculus schlechtendali, Panonychus ulmi and Tetranychus urticae, and larvae of the insects Dasineura mali and Thrips obscuratus. Survival was high (74-100%) and O. vicinus was able to complete development on all prey species in an average of 22-26 days at 20 C. The most rapid development occurred on T. obscuratus, T. urticae and P. ulmi. Adult size was estimated from the length of the fifth instar cast skin, which averaged 2.18 to 2.48 mm on different prey. The largest bugs were obtained from feeding on T. obscuratus or D. mali. O. vicinus, which were fed A. schlechtendali, were the slowest to develop and produced the smallest adults. The results are discussed in relation to prey availability and observed predation in the field, and are compared with previous feeding studies.     

Garden Money Buys Grain: Food Procurement Patterns in a Malian Village

This study of a rural Malian community in West Africa investigates food procurement patterns that combine subsistence grain production with a variety of income generating activities. It finds dependence on food purchases widespread and revenue from the own-account activities of nonhousehold heads essential to food security. Gender and the wealth of households are found to influence some, but not all, income generating activities and expenditures. Three household food procurement profiles are identified: investment in cattle, market gardens and bush extraction, and remittances. The case study village has agroecological characteristics and market proximity, which set it and other urban hinterland villages apart from the more cotton- and cattle-based zones of southern Mali. Own-account income generating activities may be able to increase revenue for women and junior men through a reallocation of household resources without entirely undermining the basis for a larger subsistence-oriented household.     

No effects of fire,large herbivores and their interaction on regrowth of harvested trees in two West African savannahs

Theory and empirical evidence for the impacts of fire and herbivory in savannahs is well established – they are top‐down disturbances that maintain savannahs in disequilibrium states away from potential tree cover. In African savannahs, the demand for fuelwood is extremely high, so tree harvest likely also has an impact, both directly and indirectly, on tree cover, density and biomass. Many savannah trees resprout vigorously from the base after harvest. However, harvested trees regenerate as saplings susceptible to fire and browsing, so harvest may have important demographic consequences. Here, we report the effects of tree harvest, and its interaction with fire and herbivory, on savannah dynamics by analysing woody regrowth following a harvest in arid Sahelian and mesic Guinean savannahs in Mali, West Africa. Tree harvest resulted in an overall reduction in wood production per tree compared to growth in nonharvested trees. Regrowth, either biomass or height, did not differ among fire and herbivory treatments. Our results suggest that the resprouting abilities that savannah trees have evolved to cope with frequent fire are essential for surviving tree harvest and subsequent disturbance. In these savannahs, regrowth is rapid enough in the first growing season to escape the impact of dry season fires.     

High Genetic Variability of Schistosoma haematobium in Mali and Nigeria

Schistosoma haematobium is one of the most prevalent parasitic flatworms, infecting over 112 million people in Africa. However, little is known about the genetic diversity of natural S. haematobium populations from the human host because of the inaccessible location of adult worms in the host. We used 4 microsatellite loci to genotype individually pooled S. haematobium eggs directly from each patient sampled at 4 endemic locations in Africa. We found that the average allele number of individuals from Mali was significantly higher than that from Nigeria. In addition, no significant difference in allelic composition was detected among the populations within Nigeria; however, the allelic composition was significantly different between Mali and Nigeria populations. This study demonstrated a high level of genetic variability of S. haematobium in the populations from Mali and Nigeria, the 2 major African endemic countries, suggesting that geographical population differentiation may occur in the regions.     

One Leg or Two? Food Security and Pastoralism in the Northern Sahel

Should pastoralists in dryland Africa diversify or specialize in their productive activities? To investigate this question, we analyze data from a consumption survey and two surveys of the nutritional status of children in addition to qualitative interviews comparing nomadic and sedentary population groups in the Gourma area in northern Mali. We show how the children of pastoralists seem to be better nourished than children of sedentary farmers and that the children of the sedentarized nomads seem to be the worst off. Based on these findings, we first argue that sedentary farming appears to be a poorer adaptation than nomadic pastoralism in arid environments such as the northern Sahel. Secondly, we argue that the diversification argument (better to stand on two legs than one) is flawed for mobile pastoralists in the northern Sahel because the logistical and organizational costs of combining different modes of livelihood are large and easily become insurmountable for a single household.     

Blending Genetics and Sociocultural Historical Inquiry: Ethics, Culture,and Human Subjects Protection in International Cross Cultural Research

In this paper, we examine the implementation and difficulties when conducting genetics research in a rural, traditional West African culture within the frame of the United States’ grounded research ethics. Research challenges are highlighted by Western researchers following U.S. Institutional Review Board (IRB) guidelines and practices in a non-Western country. IRB concepts are culture bound in Western ideals that may not have synchronicity and compatibility with non-Western cultures. Differences in sociocultural norms, traditions, language, and geography were influencing factors that can affect application of IRB principles. Suggestions for change are offered, which will potentially aid researchers considering application of IRB requirements when conducting research in non-Westernized, non-industrialized countries.