Simulating tick distributions over sub-Saharan Africa: the use of observed and simulated climate surfaces

Aim A broad suit of climate data sets is becoming available for use in predictive species modelling. We compare the efficacy of using interpolated climate surfaces [Center for Resource and Environmental Studies (CRES) and Climate Research Unit (CRU)] or high‐resolution model‐derived climate data [Division of Atmospheric Research limited‐area model (DARLAM)] for predictive species modelling, using tick distributions from sub‐Saharan Africa. Location The analysis is restricted to sub‐Saharan Africa. The study area was subdivided into 3000 grids cells with a resolution of 60 × 60 km. Methods Species distributions were predicted using an established multivariate climate envelope modelling approach and three very different climate data sets. The recorded variance in the climate data sets was quantified by employing omnidirectional variograms. To further compare the interpolated tick distributions that flowed from using three climate data sets, we calculated true positive (TP) predictions, false negative (FN) predictions as well as the proportional overlaps between observed and modelled tick distributions. In addition, the effect of tick data set size on the performance of the climate data sets was evaluated by performing random draws of known tick distribution records without replacement. Results The predicted distributions were consistently wider ranging than the known records when using any of the three climate data sets. However, the proportional overlap between predicted and known distributions varied as follows: for Rhipicephalus appendiculatus Neumann (Acari: Ixodidae), these were 60%, 60% and 70%; for Rhipicephalus longus Neumann (Acari: Ixodidae) 60%, 57% and 75%; for Rhipicephalus zambeziensis Walker, Norval & Corwin (Acari: Ixodidae) 57%, 51% and 62%, and for Rhipicephalus capensis Koch (Acari: Ixodidae) 70%, 60% and 60% using the CRES, CRU and DARLAM climate data sets, respectively. All data sets were sensitive to data size but DARLAM performed better when using smaller species data sets. At a 20% data subsample level, DARLAM was able to capture more than 50% of the known records and captured more than 60% of known records at higher subsample levels. Main conclusions The use of data derived from high‐resolution nested climate models (e.g. DARLAM) provided equal or even better species distribution modelling performance. As the model is dynamic and process based, the output data are available at the modelled resolution, and are not hamstrung by the sampling intensity of observed climate data sets (c. one sample per 30,000 km² for Africa). In addition, when exploring the biodiversity consequences of climate change, these modelled outputs form a more useful basis for comparison with modelled future climate scenarios.     

New genera,species and records of Phaneropterinae (Orthoptera,Phaneropteridae) from sub-Saharan Africa

The results of the study of many specimens preserved in different European museums are reported. The tribe Terpnistrini Brunner von Wattenwyl, 1878 is resurrected. The distribution of the following species is enhanced: Pardalota asymmetrica Karsch, 1896, Diogena denticulata Chopard, 1954, Diogena fausta (Burmeister, 1838), Plangiopsis adeps Karsch, 1896, Poreuomena sanghensis Massa, 2013 and Tylopsis continua (Walker, 1869). Further, for their peculiar characteristics, two African representatives of the American genus Symmetropleura Brunner von Wattenwyl, 1878 are included in two new genera: Symmetrokarschia africana (Brunner von Wattenwyl, 1878), comb. n. and Symmetroraggea dirempta (Karsch, 1889), comb. n. A new genus and species from the Democratic Republic of Congo, Angustithorax spiniger gen. n., sp. n., and a new genus and species from Tanzania, Arostratum oblitum gen. n., sp. n. are described. Finally Melidia claudiae sp. n. and Atlasacris brevipennis sp. n. are described and compared with related species.     

Population homeostasis in sub-Saharan Africa

Global population growth remains one of the major challenges of the twenty-first century. This is particularly true for African countries which have been undergoing their demographic transitions. To investigate whether predicted increasing population density and urbanization can help to stabilize African population, we construct a database for 84 georeferenced Demographic and Health Survey (DHS) samples including 947,191 individuals in sub-Saharan Africa and match each location with gridded population density from NASA. We apply a proportional hazard model to evaluate the quantitative impact of local population density on the transitions from childlessness to motherhood, and from celibacy to marriage. Moving from the 5th to the 95th percentile of population density increases the median age at first birth by 2.2 years. This roughly decreases completed fertility by half a child. The same increase in population density increases the median age at first marriage by 3.3 years. These findings contribute to the understanding of why fertility has not dropped in Africa as fast as expected. One part of the answer is that population density remains low. Yet the total effect of increased density on fertility remains limited and counting on it to stabilize the population would be unrealistic.     

Pollen–pollen interactions in Betula pendula in vitro

Direct pollen interactions, as well as interactions mediated by a recipient, can have a remarkable influence on pollen fertilization ability. Under conditions of pollen competition it could be advantageous if pollen grains interfered with the germination of other pollen. The aim of this study was to find out if there are direct negative or positive pollen–pollen interactions between pollen grains from genetically slightly different donors. The in vitro germinability of the pollen from several Betula pendula Roth clones was investigated. The pollen interactions between the clones were examined pairwise by using equal pollen mixtures. In three of the eight cases the germination percentage of the pollen mixture was significantly higher than the average germination percentage of the separate clones that formed the mixture, which indicates some type of interaction between the pollen populations. We found only positive interactions between the pollen of clones. This study also documented density-dependent germination of pollen grains in vitro (=pollen population effect). Adding an aqueous pollen extract to the incubation medium increased the germination percentages of poorly germinating pollen and small pollen populations. Germination-stimulating effects were found to exist both with fresh and dead pollen. Such direct pollen–pollen interactions could be explained by specific water-soluble substances diffusing from pollen grains.     

The Enchytraeid fauna of North Africa

As part of a survey of the Mediterranean enchytraeids, large numbers of samples were collected from a wide range of habitats at 38 localities of Tunisia and Algeria in 1989. Twenty species were identified belonging to six genera. Five species are new records for Tunisia and 17 are new for Algeria. Most of the recorded species are widely distributed throughout Europe, or even cosmopolitan, but some have a more restricted range. Fridericia caprensis has a circummediterranean distribution, Fridericia sardorum seems to be endemic to the western Mediterranean and Fridericia berninii is known only from the Balearic Islands and Algeria. Enchytraeus minutus bisetosus n. ssp. is described. A critical revision of some species is also provided.     

Melanin and HIV in sub-Saharan Africa

HIV is common in sub-Saharan Africa. Sexually transmitted bacterial and fungal infections increase the chance of HIV infection. Melanin can prevent the penetration of skin and mucus membranes by microorganisms, and soluble melanin can inhibit HIV replication. We suggest that melanin may reduce the incidence of HIV infection through venereally acquired skin lesions, thus reducing the risk of sero-conversion and slow the progress to AIDS. Indigenous sub-Saharan peoples are highly melanized, but there is pigment variation between populations. We show that skin reflectance, a negative correlate of melanin, is positively associated with adult rate of HIV in sub-Saharan countries. There is no such relationship in populations outside sub-Saharan Africa. We suggest that melanin concentration in black people may correlate with resistance to HIV infection.     

Taxonomy and distribution of some katydids (Orthoptera Tettigoniidae) from tropical Africa

Results of the study of specimens collected in tropical Africa and preserved in different European collections and museums are reported and extensively illustrated. The following three new species are described: Horatosphaga aethiopica sp. n., Dapanera occulta sp. n. and Cestromoecha laeglae sp. n. In addition, new diagnostic characters or distributional data for Ruspolia differens (Serville, 1838), Thyridorhoptrum senegalense Krauss, 1877, Horatosphaga leggei (Kirby, 1909), Horatosphaga linearis (Rehn, 1910), Preussia lobatipes Karsch, 1890 and Dapanera eidmanni Ebner, 1943 are reported. Finally, Symmetropleura plana (Walker, 1869) is proposed to be transferred to the genus Symmetrokarschia Massa, 2015, Conocephalus carbonarius (Redtenbacher, 1891) to the genus Thyridorhoptrum Rehn & Hebard, 1915; the genus Gonatoxia Karsch, 1889 is proposed to be synonymized with Dapanera Karsch, 1889.     

Climate–growth relationships of tropical tree species in West Africa and their potential for climate reconstruction

Most tropical regions are facing historical difficulties of generating biologically reconstructed long‐term climate records. Dendrochronology (tree‐ring studies) is a powerful tool to develop high‐resolution and exactly dated proxies for climate reconstruction. Owing to the seasonal variation in rainfall we expected the formation of annual tree rings in the wood of tropical West African tree species. In the central‐western part of Benin (upper Ouémé catchment, UOC) and in northeastern Ivory Coast (Comoé National Park, CNP) we investigated the relationship between climate (precipitation, sea surface temperature (SST)) and tree rings and show their potential for climate reconstruction. Wood samples of almost 200 trees belonging to six species in the UOC and CNP served to develop climate‐sensitive ring‐width chronologies using standard dendrochronological techniques. The relationship between local precipitation, monthly SST anomalies in the Gulf of Guinea, El Niño‐ Southern Oscillation (ENSO) and ring‐width indices was performed by simple regression analyses, two sample tests and cross‐spectral analysis. A low‐pass filter was used to highlight the decadal variability in rainfall of the UOC site. All tree species showed significant relationships with annual precipitation proving the existence of annual tree rings. ENSO signals could not be detected in the ring‐width patterns. For legume tree species at the UOC site significant relationships could be found between SST anomalies in the Gulf of Guinea indicating correlations at periods of 5.1–4.1 and 2.3 years. Our findings accurately show the relationship between tree growth, local precipitation and SST anomalies in the Gulf of Guinea possibly associated with worldwide SST patterns. A master chronology enabled the reconstruction of the annual precipitation in the UOC to the year 1840. Time series analysis suggest increasing arid conditions during the last 160 years which may have large impacts on the hydrological cycles and consequently on the ecosystem dynamics and the development of socio‐economic cultures and sectors in the Guinea‐Congolian/Sudanian region.     

Biotechnology and sustainable development in sub-Saharan Africa

Whether development is defined by the long-standing economic parameter of per capita gross national product (GNP) or by the newly introduced Human Development Index (HDI), which is not based exclusively on per capita GNP, the countries of sub-Saharan Africa rank at or near the bottom of the developing world. Agriculture and agro-based processing are the mainstays of the economies of the majority of these countries. Because of this, and also because many of the diseases endemic in these countries are communicable, the application of modern biotechnology (including genetic engineering, tissue culture and monoclonal antibody technology) and related biotechnologies could play an important part in creating sustainable development in the region. There is, therefore, an urgent need to train more of the region's indigenous citizens, and to equip more laboratories, in modern biotechnology. It is suggested that, in order to accelerate the harnessing of the fruits of biotechnology, more countries in the region should affiliate with the International Centre for Genetic Engineering and Biotechnology (ICGEB). It is further suggested that a regional equivalent of the ICGEB be built and the services of non-governmental biotechnology organizations used.The author is with Nnamdi Azikiwe University, P. M. B. 5025, Awka, Nigeria. Address correspondence to P. M. B. 1457, Enugu, Nigeria     

The national determinants of deforestation in sub-Saharan Africa

For decades, the dynamics of tropical deforestation in sub-Saharan Africa (SSA) have defied easy explanation. The rates of deforestation have been lower than elsewhere in the tropics, and the driving forces evident in other places, government new land settlement schemes and industrialized agriculture, have largely been absent in SSA. The context and causes for African deforestation become clearer through an analysis of new, national-level data on forest cover change for SSA countries for the 2000–2005 period. The recent dynamic in SSA varies from dry to wet biomes. Deforestation occurred at faster rates in nations with predominantly dry forests. The wetter Congo basin countries had lower rates of deforestation, in part because tax receipts from oil and mineral industries in this region spurred rural to urban migration, declines in agriculture and increased imports of cereals from abroad. In this respect, the Congo basin countries may be experiencing an oil and mineral fuelled forest transition. Small farmers play a more important role in African deforestation than they do in southeast Asia and Latin America, in part because small-scale agriculture remains one of the few livelihoods open to rural peoples.     

The species of the genus Micrambe Thomson 1863, from South Africa (Coleoptera: Cryptophagidae)

The 22 species of the genus Micrambe Thomson known from South Africa are analyzed and revised. Micrambe danielssoni sp. nov is described. Following a detailed study of the type material in different entomological collections, the status of two taxa is revised and two new synonymies are proposed: Micrambe kolbei Grouvelle 1908, syn. nov. for Micrambe minuta Grouvelle 1908, and Micrambe similis Bruce 1957, syn. nov. for Micrambe peringueyi Grouvelle 1908. A lectotypus is designated for one taxon: Micrambe capensis (Redtenbacher 1867). A key to all the species occurring in South Africa is presented.     

Whole-genome single nucleotide polymorphism and mating compatibility studies reveal the presence of distinct species in sub-Saharan Africa Bemisia tabaci whiteflies

In sub-Saharan Africa cassava growing areas, two members of the Bemisia tabaci species complex termed sub-Saharan Africa 1 (SSA1) and SSA2 have been reported as the prevalent whiteflies associated with the spread of viruses that cause cassava mosaic disease (CMD) and cassava brown streak disease (CBSD) pandemics. At the peak of CMD pandemic in the late 1990s, SSA2 was the prevalent whitefly, although its numbers have diminished over the last two decades with the resurgence of SSA1 whiteflies. Three SSA1 subgroups (SG1 to SG3) are the predominant whiteflies in East Africa and vary in distribution and biological properties. Mating compatibility between SSA1 subgroups and SSA2 whiteflies was reported as the possible driver for the resurgence of SSA1 whiteflies. In this study, a combination of both phylogenomic methods and reciprocal crossing experiments were applied to determine species status of SSA1 subgroups and SSA2 whitefly populations. Phylogenomic analyses conducted with 26 548 205 bp whole genome single nucleotide polymorphisms (SNPs) and the full mitogenomes clustered SSA1 subgroups together and separate from SSA2 species. Mating incompatibility between SSA1 subgroups and SSA2 further demonstrated their distinctiveness from each other. Phylogenomic analyses conducted with SNPs and mitogenomes also revealed different genetic relationships among SSA1 subgroups. The former clustered SSA1-SG1 and SSA1-SG2 together but separate from SSA1-SG3, while the latter clustered SSA1-SG2 and SSA1-SG3 together but separate from SSA1-SG1. Mating compatibility was observed between SSA1-SG1 and SSA1-SG2, while incompatibility occurred between SSA1-SG1 and SSA1-SG3, and SSA1-SG2 and SSA1-SG3. Mating results among SSA1 subgroups were coherent with phylogenomics results based on SNPs but not the full mitogenomes. Furthermore, this study revealed that the secondary endosymbiont—Wolbachia—did not mediate reproductive success in the crossing assays carried out. Overall, using genome wide SNPs together with reciprocal crossings assays, this study established accurate genetic relationships among cassava-colonizing populations, illustrating that SSA1 and SSA2 are distinct species while at least two species occur within SSA1 species.     

Reflections on clinical research in sub-Saharan Africa

The urgent need for new, safe and sustainable interventions against diseases that disproportionally affect the poor is finally receiving global attention and the funding landscape for development projects has significantly improved during the past decade. For the development of new drug and vaccine candidates, clinical trials have become the most important tool to assess their safety and efficacy. Recently, there has been a seismic shift in the number of clinical trials conducted in resource-limited settings. We discuss the current framework of clinical research in sub-Saharan Africa, from building product pipelines to the capacities needed for the conduct of trials according the harmonised Good Clinical Practice (GCP) ICH E6 guideline. We place emphasis on clinical research in neglected tropical diseases which still frequently has to be conducted with limited financial, logistical and human resources. Given those short-comings we recommend minimum standards needed at the local, national and sponsor levels to provide GCP-compliant clinical research.     

A new species, Gazza squamiventralis, from the East Coast of Africa (Perciformes: Leiognathidae)

Gazza squamiventralis sp. nov. is described as the fifth species of the genus, based on the holotype and eight paratypes, 42–96 mm in standard length, collected along the east coast of Africa, from Kenya to Mozambique. The species is similar to other congeners in general appearance, differing clearly from them in having the ventrolateral surface of the body scaled anterior to a line from the pectoral fin base to the pelvic fin origin (vs naked) and a smooth supraorbital ridge (vs finely serrated). Additionally, the species differs from G. dentex, G. rhombea, and G. achlamys in having the dorsolateral surface of the body scaled anterior to a vertical through the tip of the posterior branch of the supratemporal canal (vs corresponding region naked), and from G. minuta in having the first dorsal fin pterygiophore narrowly expanded anteriorly, with a concave margin (vs broadly expanded, with a convex or linear margin), and a short antrorse extension of the first anal fin pterygiophore (vs long). A key to the five species of the genus Gazza is provided. Received: May 30, 2000 / Revised: September 16, 2000 / Accepted: January 16, 2001     

Diversity patterns of the terrestrial snail fauna of Nyungwe Forest National Park (Rwanda), a Pleistocene refugium in the heart of Africa

We investigated the land snail fauna of Nyungwe Forest National Park in south‐western Rwanda. Fifty plots at altitudes between 1718 and 2573 m were studied. In total, 3461 specimens were collected and were assigned to 102 land snail species. With respect to land snail species, Nyungwe Forest is the richest forest known in Africa. A comparison with other forests in the northern Albertine Rift indicates that land snail species richness in this region is significantly correlated with distance from Pleistocene forest refugia. The high beta diversity in Nyungwe is the result of a high species turnover between sites, which has biogeographical and ecological origins. Nyungwe Forest is situated on the Congo–Nile divide where species of different geographical origin may meet. Moreover, Nyungwe Forest offers a high diversity of habitats because it extends across a wide range of altitudinal zones. Species richness decreased with increasing altitude. It was also correlated with the presence of bare rocks that offer additional microhabitats and shelter. Although the occurrences of different land snail species in Nyungwe Forest were significantly clustered, only a minority of the species could be assigned to a group of species with similar occurrences. The majority of the species respond individualistically to environmental variables. The significant nestedness of the occurrences of the land snail species in Nyungwe was mainly correlated with altitude. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 114 , 363–375.     

黄美乳菇(红菇目,红菇科),中国首个乳菇属变红乳菇亚属中乳汁变黄的物种

红菇属变红乳菇亚属的乳汁常变为红色,变黄的乳汁较为少见.在中国中南部亚热带壳斗科林下发现了一个乳汁迅速变黄色的物种.这是首次在中国发现的变红乳菇亚属中乳汁变黄的物种,其独特的乳汁、褐色的菌盖、稀疏的菌褶和大的具极高翼状纹饰的孢子能将其与其他已知种区分开来,在此将其描述为新种,黄美乳菇L.mirus.本研究提供了该新种的...     

A new species of Exostyles (Leguminosae, Papilionoideae, Swartzieae s.l.), from Paraná State, Brazil

A new species Exostyles godoyensis Soares-Silva & Mansano (Leguminosae, Papilionoideae, Swartzieae), endemic to Paraná state in southern Brazil, is described and illustrated. The new species is distinct from all the other species of Exostyles in having a leaf with up to five leaflets, while the other species have at least seven leaflets per leaf. The new species is distinct from Exostyles amazonica Yakovlev in its longer stamen filaments and ovary stipe and from E. glabra Vogel and E. venusta Schott by its shorter anthers. In addition to these morphological characters E. godoyensis has a disjunct geographical distribution.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 146 , 103–106.     

Breast cancer in sub-Saharan Africa: The current state and uncertain future

Breast cancer is the commonest cause of global cancer-related deaths in women and a public health burden in sub-Saharan Africa (SSA). Although the disease incidence in SSA seems lower, mortality rates are disproportionately high in comparison to high-income countries. The global disease burden is growing, with SSA reporting the majority of cases; however, the dearth of information results in insufficient data which is barely representative of the actual disease burden in this population. Future incidence predictions assign the subregion with a majority of the cases and associated deaths. Breast cancer presents with racial and ethnic variations, and available evidence suggests geographical diversity and persistent risk factors that have barely been explored in SSA. Breast cancer is a complex genetic disease, but the genetic risk factors in the extant African population, which is the most genetically diverse population, is scant and of low quality. This review focuses on the burden, prevalence, detection, treatment, survival, biology, as well as risk factors, and reinforces the need for breast cancer-associated risk factor investigation and population-specific studies in SSA.