Jacques François Mavoungou

Spatio-temporal variation of biting flies, Stomoxys spp. (Diptera: Muscidae), along a man-made disturbance gradient, from primary forest to the city of Makokou (North-East, Gabon)

Understanding the pattern of abundance of vector populations is important to control the potential of transmission of associated pathogens. The pattern of abundance of Stomoxys Geoffroy, an ubiquitous blood‐sucking fly, is poorly known in tropical Africa. In this study, we investigated the spatio‐temporal pattern of abundance of the Stomoxys genus along a gradient of man‐made disturbance in north‐eastern Gabon. Three sites (one in primary forest, one in secondary forest and one in a man‐made environment) were monitored during 13 months using Vavoua traps. Seven species and subspecies were found to live in sympatry, but with distinct patterns of abundance with respect to space and time. The most abundant species was Stomoxys transvittatus Villeneuve, whereas the rarest species was S. xanthomelas Roubaud. Stomoxys calcitrans Linné was preferentially found in man‐made environments, whereas S. xanthomelas was preferentially found in primary forest. Stomoxys abundance was the greatest in secondary forest, then in man‐made environments and finally in primary forest. A seasonal variation in Stomoxys abundance was also found. In conclusion, forest degradation and deforestation are likely both to favour the concentration of populations of Stomoxys, and to change the specific composition of the Stomoxys community.

Distribution and abundance of hematophagous flies (Glossinidae, Stomoxys, and Tabanidae) in two national parks of Gabon

In order to minimize risks of pathogen transmission with the development of ecotourism in Gabon, a seasonal inventory has been performed in five contrasted biotopes in Ivindo (INP) and Moukalaba-Doudou (MDNP) National Parks. A total of 10,033 hematophagous flies were captured. The Glossinidae, with six different species identified, was the most abundant group and constitutes about 60% of the captured flies compared to the Stomoxys (6 species also identified) and Tabanidae with 28% and 12%, respectively. The Glossinidae showed a higher rate of capture in primary forest and in research camps. In INP, the Stomoxys showed a higher rate of capture in secondary forest and at village borders, whereas in MDNP the Stomoxys were captured more in the savannah area. Thus, each fly group seemed to reach maximum abundance in different habitats. The Glossinidae were more abundant in primary forest and near research camps while Stomoxys were more abundant in secondary forest and savannah. The Tabanidae did not show a clear habitat preference.

Inventaire des mouches hématophages dans les élevages bovins, ovins et porcins à Oyem (Nord Gabon)

La Communaute Electrique du Benin (CEB) est la seule structure commune au Benin et au Togo qui fournit aux deux pays de l’energie electrique. L’optimisation de son reseau de transport d’energie electrique est d’une importance capitale. Ainsi, la synchronisation de ses importants sous reseaux, a savoir la Volta River Authority (VRA) et la Transmission Company of Nigeria (TCN), vise non seulement a faciliter l’exploitation du reseau mais aussi a l’optimiser afin de reduire les desagrements causes aux populations Beninoise et Togolaise. Cette synchronisation depend ainsi des parametres electriques des reseaux TCN et VRA. Nous avons etudie la faisabilite de cette synchronisation en proposant un systeme High Voltage Direct Curent (HVDC) que nous avons simule sous le logiciel Matlab/SimPowerSystems. Mots-cles : energie electrique, synchronisation, optimisation, HVDC, reseau electrique.

Breeding Sites of Stomoxys spp (Diptera: Muscidae), a Preliminary Study in the Makokou Region (North-East-Gabon)

In order to circumscribe the breeding sites of stomoxes in the Makokou region, eight potentially favorable environments were sampled from January to June 2007 in three habitats: primary and secondary forest (natural environments) and the anthropic environment (artificial or disturbed areas). In the primary forest, three types of substrates were collected: litter, elephant dung and Cephalophus droppings. In the secondary forest, two types of substrates: litter and monkey droppings. In villages or cities, three substrates constituting of: decaying plant material, organic waste from garbage in villages and cow dung were also collected. These materials were placed in emergence cages while awaiting the emergence of adult arthropods. In total, 14517 arthropods emerged, including 11726 stomoxes and 2791 other arthropod specimens. Seven Stomoxys spp were observed and included: S. transvittatus with 8221 (70%) emerged individuals, S. niger niger with 1679 (14%) observed individuals. However, S. omega (8%); S. inornatus (4%); S. calcitrans (2%); S. niger bilineatus (1.9%); and finally S. xanthomelas (0.1%) emerged in minor proportions. The results obtained in this study indicate that stomoxes can lay their eggs on several types of substrates hence colonizing many areas

Vegetarian diet in Guenon and Mangabey monkeys of Moukalaba-Doudou National Park, Gabon: similarities and differences

To order to know any differences and similarities between Mangabeys and Guenons study of their vegetarian diet was conducted for 10 months between 2013 and 2014 in Moukalaba-Doudou National Park, Gabon. By using the direct observation method, we identified 84 plant species integral to the vegetarian diet of these two groups of monkeys. Thus, we have recorded similarities and differences. Guenons (69 species) consume the same plant species as the Mangabeys (49 species; V = 1594 p-value = 0.1796). They are considered frugivores at large because they consume an average of 84.77% fruit for guenons and 63.37% for the mangabeys, with a difference in the consummation of seeds 18.93% and 3.31% respectively. These results suggest that Mangabey have a seed-eating regime while the guenons tend to consume even when they are unavailable fruits. Our analyzes also showed that these two groups have preference different family of the species that they consume. This is due to the nature of the fruit produced by each family. Furthermore the mangabey (chi-squared = 5.6989, df = 5, p-value = 0.3366) interested in several of plants while monkeys (chisquared = 15.817, df = 5, p-value = 0.007387) remain more attached to fruit consumption.

Etude de la Relation entre l’abondance des grands mammifères frugivores et celle des fruits dans le Parc National de Moukalaba-Doudou, Gabon

Au Gabon, les travaux portant sur les relations plantes animaux demeurent encore tres lacunaires. Pourtant, cette connaissance est indispensable dans la comprehension des fonctionnements des ecosystemes forestiers, mais aussi sur le comportement alimentaire des mammiferes. C’est dans ce cadre qu’une etude sur l’abondance des mammiferes frugivores et celles des fruits a ete conduite dans le Parc National de Moukalaba Doudou. Les donnees sur l’abondance des mammiferes ont ete recueillies a l’aide des cameras pieges, le long de 11 transects de janvier 2012 a janvier 2014. Quant aux fruits, ils ont ete recoltes le long de ces transects sur une bande de 1 m de large de part et d’autre du transect. Au total, 2492 fruits repartis en 100 especes ont ete recenses au cours de cette etude. Le nombre de fruits recenses a varie en fonction des biotopes prospectes et des mois. Les cameras pieges ont permis d’identifier dix especes de mammiferes frugivores presents dans cette zone. Le test de correlation P de Pearson (R= 0,2 ; df= 10, P= 0,5) a montre que la variation entre l’abondance des mammiferes et celle des fruits reste independante. Mots cles : Abondance, fruits, mammiferes, Parc National Moukalaba-Doudou, camera piege, Gabon.

High Frequency of (Kinetoplastida: Trypanosomatidae) Type Among (Diptera: Glossinidae) in a Historic Trypanosoma Foci in North-Eastern Gabon: Preliminary Study

Abstract Human African trypanosomiasis became a neglected disease after the 1960s, when case numbers dropped dramatically. It again became a public health problem in sub-Saharan Africa at the end of the 1990s, when new cases were reported, notably in Central Africa, and specifically in Gabon, where historic foci existed and new cases have been reported. Therefore, the present study reports on an entomological survey conducted in May 2012 to determine the pathogenic trypanosome infection rate in tsetse flies and characterize the diversity of Trypanosoma species in the Ivindo National Park (INP) in northeastern Gabon. Nine Vavoua traps were used to catch tsetse over a 7-days period. All tsetse flies captured were identified to species, dissected, and trypanosome species identified using polymerase chain reaction (PCR). In total, 160 tsetse flies were analyzed, including Glossina palpalis palpalis, Glossina fusca congolense, and Glossina tachinoïdes. The trypanosome infection rate of the flies was 6.3 and 31.9% using microscopy and PCR, respectively. The species identified were Trypanosoma congolense savannah type, Trypanosoma brucei brucei, Trypanosoma brucei gambiense, Trypanosoma vivax, and Trypanosoma congolense forest type. Trypanosoma risk index was 0.75 and 7.05 for humans and for animals, respectively. This study illustrates the diversity of Trypanosoma species infecting the tsetse flies in the INP. The simultaneous occurrence of Trypanosoma and tsetse from the palpalis group may suggest that the reservoirs of African animal trypanosomiasis should be carefully monitored in this area.

Identification et caractérisation de la dynamique de la grande faune dans le baï de Momba (nord-est Gabon)

Les bais sont des clairieres marecageuses localisees generalement au coeur des forets du Bassin du Congo. Ce sont des ecosystemes particulierement riches en especes animales et vegetales. Si les connaissances portant sur l’origine de ces milieux sont bien documentees, les especes de la faune sauvage (elephants, buffles, sitatungas, etc.) colonisant ces ecosystemes demeurent encore mal connues. Par ailleurs, les informations qui existent sur ces especes fauniques restent fragmentaires. C’est pour ces raisons qu’une etude basee sur les methodes d’observation de la faune (scan sampling et animal focal) a ete conduite dans le bai de Momba durant 33 jours. Ce travail visait l’identification de la macrofaune presente dans ce type de milieux et l’analyse de la dynamique de cette faune. Au total, 969 animaux ont ete observes. Ces animaux ont ete representes majoritairement par les sitatungas (Tragelaphus spekei), les elephants (Loxodonta africana cyclotis), les buffles (Syncerus caffer nanus) et les colobes (Colobus guereza). En termes de frequence d’observation, les sitatungas (27%) ont ete le groupe le plus abondant, suivis par les elephants (8%) et les buffles (7%). Les autres animaux ont ete faiblement observes avec une frequence de moins de 2%. La frequentation du bai de Momba par ces especes temoigne du role crucial que pourrait jouer les zones humides dans la gestion durable de la biodiversite dans le Bassin du Congo. Aussi, il apparait necessaire que des mesures de protection et de suivi de la dynamique de ces peuplements soient rapidement entreprises afin de proteger la biodiversite faunique de ce milieu. Mots cles : Loxodonta africana cyclotis, Syncerus caffer nanus, Tragelaphus spekei,Colobus guereza , bai de Momba, Gabon.