ZEPHIRIN TADU · UY1 Research Hub

BPA

ZEPHIRIN TADU

Chargé de Cours

33Publ.

BPADép.

FSFaculté

Institution: Université de Yaoundé I
Faculté
Département
Email professionnel: zephirin.tadu@facsciences-uy1.cm

Activité scientifique

Synthèse des publications

Période: 2009–2025
Accès ouvert: 9
Types: 3
Publ.: 33

Journal Article · 28
Other · 4
Book · 1

Mots-clés récurrents

biology
ecology
insect and arachnid ecology and behavior

Profil chercheur

Biographie

Enseignant-chercheur à l’Université de Yaoundé I. Grade : Chargé de Cours.

Publications scientifiques

Publications

2025

2025Article de revue
characterization of termite assemblages on Yaoundé's urban and peri-urban natural forest remains
Pierre Akama, Zéphirin Tadu, Not Yede, Michelle Mbida, Paul Serge Mbenoun Massé, Sáenz David
Journal of Biological Research and Reviews.
Among the many human activities that cause diversity loss, urban development produces some of the greatest local extinction rates and frequently eliminates the large majority of species. The aim of this study is to evaluate termite’s diversity in some natural relict forests of the city of Yaoundé. These relict forests persist in mountainous areas where anthropogenic activities are limited due to a very steep slope. Because of this, the study was conducted in four mountains of these areas: Messa, Akok Ndoé, Mbokdoum, and Nkolondom. The experimental design at each site consists of a block of 10,000 m2, in which twenty elementary non-contiguous sections of 5 m x 2 m were delimited. Forty-eight termite’s species, distributed in soil-feeding, wood-feeding and fungus-growing termites, have been identified. The statistical analysis revealed that abundance and species richness of termites were similar between the four sampling sites. This may be due to a convergent response of termite assemblages to the same regime of disturbances; but diversity was higher in the Messa site than in the other sites. The urban-rural diversity gradient regularly observed in previous researches has not been detected in this study. This result demonstrates that the disturbance gradient is the main driver regulating diversity in this part of the Congo Basin. Moreover, the Spearman test showed a significant correlation between pHwater and abundance of wood-feeding termites.
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2024

2024Article de revueAccès ouvert
Diversity and functional structure in ant community in a forest savannah transitional zone in Obala (Centre Region of Cameroon)
Zéphirin Tadu, Kwuidja Ngajeu Marey-Marvell, Yédé, Edoa Stephanie, Guibaï Jean-Pierre, Lekeufack Nguefack Gustave et 3 autre(s)
BIODIVERSITY JOURNAL
We study ant community in Obala (Cameroon), a forest-savannah ecotone to determine diversity and functional structure. Ants were sampled using pitfall, bait and hand-collecting in four habitats. Ant community was characterized using genera and species richness per subfamily, species richness and Pielou index for diversity, Venn diagrams for the distribution of species richness, multinomial model and Individual value to determine habitat specialization, and Multiple Correspondence Analysis to identify functional structure. We identified 104 ant species belonging to 34 genera and six subfamilies; 90, 31, 35 and 17 ant species were collected respectively in cocoa farms, food crops plantations, teak forests and savannahs. Myrmicinae, Ponerinae and Formicinae were the richest subfamilies at genera and species levels. Cocoa farms were richer and more diverse (S = 90; E = 0.68) than other habitats. Eight species were shared amongst the four habitats and the high number of generalist species occurred between cocoa farms and teak forests. Indicator species were mainly ground-dwelling ant species, confirming the high level of environmental threat in Obala. Four functional structures were identified: non-dominant ground foraging species with low ability for space control; tree foraging species with low ability for food control found in cocoa farm; subdominant species that exert medium level of food and space control; and ubiquist numerically dominant ant species with high aptitude for food and space control. In a functional structure involving ant species that plays the same or complementary roles in the ecosystem functioning and determine network of species assemblages.
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2023

2023Article de revueAccès ouvert
Biological diversity of arthropods associated with two varieties of pepper (Capsicum annuum L., 1753) at Nkolmelen (Yaoundé, Cameroon)
Audrey Valtery Voula, Désirée Chantal Aléné, Zéphirin Tadu, E. F. Manga, G. Zang-Affa’a, Champlain Djiéto-Lordon
International Journal of Biological and Chemical Sciences
Pepper is a vegetable which plays an important role in the human diet and health. Many insects attack this plant and decrease its production in the absence of appropriate phytosanitary treatment. Thus, the objective of the present study was to record the arthropods associated with the yellow and red pepper varieties. For this purpose, weekly observations were conducted during two cropping cycles on 192 plants, using a completely randomized device. As results, the fauna of the pepper was very diverse and stable (specific richness 47 and Equitability index 0.86). The yellow pepper was the most sensitive with an average of nine insect species per plant versus eight on the red pepper. These insects belonged to seven orders (Arachnida, Coleoptera, Diptera, Hemiptera, Hymenoptera, Lepidoptera and the Orthoptera), 28 families and 47 species. The densest orders were Diptera represented by Ceratitis capitata, Silba capsicarum, followed by Hymenoptera were represented by Camponotus floridanus, Camponotus acvapimensis and Crematogaster sp. and Hemiptera represented by Aphis gossypii, Macrosiphum euphorbiae, Pseudococcus sp. The present study provided a database on arthropodofauna of the pepper plant. This is of paramount importance for the development of healthy and sustainable protection strategies among pepper producers in order to improve national production.
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2022

2022Article de revue
Relation between ground‐dwelling and arboreal ant diversity in three vegetation types in the humid forest zone of southern Cameroon
Zéphirin Tadu, Guibai Jean Pierre, Messop‐Youbi Edith Blandine, Edoa Stephanie, Fomekong‐Lontchi Judicaël, Aléné Desirée Chantal et 1 autre(s)
African Journal of Ecology
Abstract Though ant diversity was well documented, relations between ground‐dwelling and arboreal ants were poorly known. It was in this mind that we compared species diversity and composition between ground‐dwelling and arboreal ant in three type of habitats at Mfou, a suburban agglomeration of Yaoundé city in Cameroon. Ants were collected in secondary forests, cocoa farms, and palm groves using pitfall, baits and visual catch. Ant communities were characterised using species richness and Shannon diversity index. Nonmetric Multidimensional Scaling (NMDS) and Venn diagrams were used to determine respectively species composition and the number of exclusive and shared species between types of habitats. We recorded 144 ant species belonging to 39 genera and 6 subfamilies. Ground‐dwelling ants were richest and diversified in secondary forests, while arboreal ant fauna was in cocoa farms. Arboreal ant community in palm groves was closed to that found on the ground in all type of habitats. Suggesting that, when a deep modifications occurred in a natural habitat, arboreal ant fauna could not establish permanent colonies. Therefore, trees canopies were colonised by some ground‐dwelling ant species who progressively substituted arboreal ant on the trees. Consequently, arboreal ant became progressively rare with intensification of anthropogenic disturbance and habitat loss.
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2021

2021Article de revue
A comparative assessment on ant communities in three vegetation types located at Mfou Suburban locality of Yaoundé (Cameroon)
Zéphirin Tadu, Edoa Stephanie, MESSOP YOUBI EDITH-BLANDINE, Guibaï Jean-Pierre, Judicael Fomekong‐Lontchi, Désirée Chantal Aléné et 1 autre(s)
Journal of Insect Biodiversity
Urban expansion in Cameroon and many other Congo basin countries, involves the destruction of natural habitat previously colonized by a rich and diversified invertebrate and vertebrate fauna. In order to understand the dynamic of transformation of natural landscape into urban area on ant communities, a study was conducted at Mfou, a suburban agglomeration of Yaoundé. We aimed to evaluate the variation in ant diversity and ant community structure in relation to the type of habitat. Ants were collected on the ground and trees in cocoa farms, secondary forests, and palm groves using visual catch, pitfall traps, quadrat, and baits. We recorded 144 species belonging to 39 genera and 6 subfamilies. Cocoa farms (S= 102; H’= 3.83; E=0.83) were richer and more diversified than secondary forests (S= 100; H’= 3.83; E=0.83) and palm groves (S= 70; H’= 3.61; E=0.85). Myrmicinae, Formicinae and Ponerinae were the richest subfamilies both at genus and species levels. Based on their frequency of occurrence, Myrmicaria opaciventris (18.6%), Crematogaster striatula (17.1%), Crematogaster gabonensis (14.9%) and Camponotus crawleyi Emery, 1920 (14.2%) species were numerically dominant. Strumigenys sp.1, Strumigenys sp.2, Strumigenys sp.3, and Strumigenys sp.4 species were found only in secondary forests, suggesting the relatively stability of this habitat despite anthropogenic disturbance. Camponotus brevicollis, Technomyrmex sp.2 and Tetramorium guineensis were the indicator species in cocoa farms. In the secondary forests, Camponotus wellmani, Hypoponera punctatissima and Pheidole pulchella were found as indicator species while in palm groves H. punctatissima was the only indicator species.
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2020

2020Article de revueAccès ouvert
BIOLOGICAL DIVERSITY OF INVERTEBRATE FAUNA CIRCULATING IN SOME CUCURBIT-BASED MARKET GARDENING AGROSYSTEMS AT MINKO'O (SOUTH REGION, CAMEROON)
Stéphanie Kakam, Gaelle Didi Mokam, Desiree-Chantal Alene, Zéphirin Tadu, Judicaël Fomekong Lontchi, Gertrude-Loveline Tchoudjin et 2 autre(s)
International Journal of Agriculture Environment and Bioresearch
Market gardening, one of the predominant activities in developing countries in general and in Cameroon in particular, is nowadays threatened by pests of several animal taxa. These pests cause important yield losses and impose frequent and anarchical applications of large spectrum pesticides that alter product and environment quality. In the perspective of designing a study program on the ecology of major pests of cultivated cucurbit-based agrosystems, the present study aimed at assessing the biological diversity of the invertebrate circulating in these agrosystem. Data were collected at Minko'o, South Region of Cameroon by visual observations in experimental trap gardens from 2015 to 2017. A total of 412 species of 117 families and orders of Invertebrates were identified from a set of 40,741 individuals. This sample comprise Insecta (13 orders), Diplopoda (two orders) and Arachnida (3 orders) and two orders of Gastropoda. The numerically most important orders were Hymenopterans, Hemipterans, Coleopterans, Orthopterans, and Lepidopterans representing 88.67% of the total abundance. The numerically dominant species belonged mainly to these orders. In relation with host plant preferences, all these orders, families and species showed variable level of selectivity as comparisons of their distribution among studied plants appeared different from one taxon to another.
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2019

2019Article de revue
Ant assemblage structure on cocoa trees in smallholder farms in the Centre Region of Cameroon
Zéphirin Tadu, Régis Babin, Aléné Desirée Chantal, Yédé, Messop‐Youbi Edith Blandine, Wouter Dekoninck et 1 autre(s)
African Journal of Ecology
Abstract We investigated the ant community structure in cocoa farms in the Centre Region of Cameroon. Ants were collected on the cocoa trees during the years 2006 and 2007 using chemical knock‐down. We tested the hypothesis of the existence of deterministic factor in the structuration of ant mosaic using C‐Score; we assessed the relationship between the numerical dominant and subdominant ant species using Spearman correlation test and discussed on the influence of vegetation structure and farm management on the ant community structure. A total of 53 ant species belonging to 20 genera and five subfamilies were identified from a set of 51,525 workers collected. C‐score analysis supported the hypothesis that ant community were structured by competition. Negative relationships were found between dominant ant species. Farming practices which were mainly pruning, chemical treatment and habitat structure appeared to influence the ecological status and distribution of dominant ant species.
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2018

2018Article de revue
Identifying Ant-Mirid Spatial Interactions to Improve Biological Control in Cacao-Based Agroforestry System
Leïla Bagny Beilhe, Cyril Piou, Zéphirin Tadu, Régis Babin
Environmental Entomology
The use of ants for biological control of insect pests was the first reported case of conservation biological control. Direct and indirect community interactions between ants and pests lead to differential spatial pattern. We investigated spatial interactions between mirids, the major cocoa pest in West Africa and numerically dominant ant species, using bivariate point pattern analysis to identify potential biological control agents. We assume that potential biological control agents should display negative spatial interactions with mirids considering their niche overlap. The mirid/ant data were collected in complex cacao-based agroforestry systems sampled in three agroecological areas over a forest-savannah gradient in Cameroon. Three species, Crematogaster striatula Emery (Hymenoptera: Formicidae), Crematogaster clariventris Mayr (Hymenoptera: Formicidae), and Oecophylla longinoda Latreille (Hymenoptera: Formicidae) with high predator and aggressive behaviors were identified as dominant and showed negative spatial relationships with mirids. The weaver ant, O. longinoda was identified as the only potential biological control agent, considering its ubiquity in the plots, the similarity in niche requirements, and the spatial segregation with mirids resulting probably from exclusion mechanisms. Combining bivariate point pattern analysis to good knowledge of insect ecology was an effective method to identify a potentially good biological control agent.
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2017

2017Article de revue
Impact of the invasive ant Wasmannia auropunctata (Formicidae: Myrmicinae) on local ant diversity in southern Cameroon
Paul Serge Mbenoun Massé, Maurice Tindo, Martin Kenné, Zéphirin Tadu, Ruth Mony, Champlain Djiéto‐Lordon
African Journal of Ecology
Abstract The little fire ant, Wasmannia auropunctata Roger, is one of the world's most destructive invasive ants. It has been present in Cameroon for more than four decades, but its impact on local ant diversity is not known. We studied impact of W. auropunctata in three disturbed habitats located in rural and urban areas. We monitored ant diversity in both invaded and noninvaded zones in each area using a combination of three sampling methods: bait, pitfall traps and visual catch in quadrat. We collected 28 species in urban area and 64 in rural area. In invaded zone, W. auropunctata made up 97.72% and 99.96% of all ant fauna and ant species richness decreased to 7 and 2 in urban and rural area, respectively. In accordance with others findings in introduced environments, the presence of W. auropunctata has severely reduced abundance and richness of local ant species in both urban and rural environments in Cameroon. Measures should therefore be put in place to prevent its introduction in natural environment as forest reserves and natural parks.
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2015

2015Article de revue
Diversity and agronomic impact of rice stem borer at Nkolbisson, Yaoundé-Cameroon (Central Africa)
Karine Moche, Champlain Djieto Lordon, Zéphirin Tadu, Didi Gaëlle Mokam, Paul Alain Nana, Zéphyrin Fokam et 1 autre(s)
Today, rice has become one of the most consumed cereals in Africa in general and Cameroon in particular. The low domestic production imposes a strong import that accentuates the country&apos;s trade imbalance. To reduce this issue of external dependency, the national government is encouraging domestic production. However, producer’s efforts are inhibited by various constraints among which the pest attacks in general and in particular the stem borers. Data collection was based on sampling and incubation of white rice panicles in an experimental plots set up at Nkolbisson, Yaoundé. The susceptibility of rice varieties to different pest species was evaluated by comparing the frequency of pest species on their infested panicles. Among the NERICA rice lines, NERICA 3 had the greatest percentage of attacks panicles that was 41.96 % while NERICA 9 and 13 had the less percentage of attacks panicles that was 14.29 % for both of them. A total of three pest species were identified from the panicles incubated, Orseolia oryzivora, Chilo zacconius and Diopsis apicalis, O. oryzivora being the most frequent. NERICA 3 with 41.96 % of incubated panicles appears to be the most susceptible variety, while the Japanese’s Akitakomachi and
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2014

2014Article de revue
AGRO-MORPHOLOGICAL CHARACTERIZATION OF TWO RICE VARIETIES FROM JAPAN; ORYSA SATIVA L. AND FOUR NERICAS VARIETIES IN AN AGRO-ECOLOGICAL ZONE OF THE TOWN OF YAOUNDE (CAMEROON); COMPARATIVE STUDY OF THEIR PERFORMANCES
Karine Moche, Champlain Djieto Lordon, Marie Noel Melie Feyem, Zéphirin Tadu, Paul Alain Nana, Zéphyrin Fokam et 2 autre(s)
HAL (Le Centre pour la Communication Scientifique Directe)
International audience
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2014Article de revue
Ant Diversity in Different Cocoa Agroforest Habitats in the Centre Region of Cameroon
Zéphirin Tadu, Champlain Djiéto‐Lordon, Yédé, E.B. Messop Youbi, Abraham Fomena, Régis Babin
African Entomology
Agroforestry systems may represent refugia for native fauna in highly disturbed environments. In the context of ongoing intensive destruction of tropical rainforest by agricultural activities, there is a wealth of information on the influence of agricultural practices on arthropod diversity on southern Cameroon cocoa farms. The present study examined the diversity and the composition of ant communities on traditional cocoa farms in relation to agricultural practices along a south—north latitudinal gradient in the Centre Region of Cameroon. Ants were sampled in 21 plots using the chemical knock-down technique, along a latitudinal gradient from Ngomedzap (forest) in the south through Obala (forest-savanna) to Bokito (savanna) in the north. Species richness, Shannon diversity index and Bray-Curtis distance were used to characterize diversity of ant communities and their dissimilarity between habitats. A total of 66 ant species, belonging to 24 genera and seven subfamilies were identified from a sample of 114 843 workers. The ant diversity of Obala is higher than that of Ngomedzap and Bokito. Estimation of Bray-Curtis distances demonstrated that the ant communities of Ngomedzap and Obala were similar to each other, but very different from that of Bokito. The ant communities of Centre Cameroonian cocoa farms appeared relatively diversified. These communities varied in species composition and diversity in relation to agricultural practices along south—north latitudinal gradients.
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2013

2013Article de revue
Influence of insecticide treatment on ant diversity in tropical agroforestry system: Some aspect of the recolonization process
Zéphirin Tadu, Champlain Djiéto‐Lordon, Régis Babin, Edith Blandine Messop-Youbi, Abraham Fomena
Agritrop (Cirad)
In order to assess the influence of insecticides treatment on ant diversity and recolonization processes in cocoa based agroforestry systems, sampling was performed using chemical knock-down technique during two consecutive cocoa campaigns (2006 and 2007) in six smallholding cocoa farms located in tree localities of the Centre Region of Cameroon. These localities are located along the South-North agroecological benchmark ranging from Ngomedzap in the humid tropical rainforest in the south through Obala in mixed degraded forest / savannah in the transitional zone to Bokito in savannah landscape. From sampled ants, community diversity was measured using Shannon index and similarities between communities calculated using the Bray Curtis distance. After one-year recolonization following insecticide treatment, species richness increased in all the study sites, from 23 to 48 species at Ngomedzap, from 39 to 46 at Obala, and from 37 to 40 at Bokito. The diversity index increased from 2.15 to 2.29 at Obala while decreasing respectively from 2.12 to 2.04 at Ngomedzap and from 2.0 to 0.89 at Bokito. After one year recolonization following treatment, a total of 35 newly establish ant species were observed. Among them 11 were arboreal and two ground-nesting species. Comparison of the community composition and population size between the two sample periods suggested that certain arboreal nesting species such as Oecophylla longinoda, Tetramorium aculeatum and some species of the genus Crematogaster may survive insecticide treatment, thanks to their nesting behaviour. Also, recolonization process may be strongly influenced by border effects.
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2012

2012Autre
Distribution spatiale des fourmis arboricoles Hymenoptera : Formycidae dans les systèmes agroforestiers traditionnels du cacao
Zéphirin Tadu, Régis Babin, Désirée Chantal Aléné, Yédé, Edith Blandine Messop-Youbi, Abraham Fomena
Agritrop (Cirad)
À partir de méthodes d'analyse spatiale, les caractéristiques de distribution des fourmis ont été étudiées dans trois exploitations cacaoyères traditionnelles dans la Région Centre du Cameroun. L'étude a été menée dans le but d'évaluer (1) l'influence du système d'ombrage sur la distribution des fourmis et (2) la dynamique spatiale et temporelle des populations de fourmis sous l'effet d'un traitement insecticide. Pour la réaliser, des parcelles de 100 cacaoyers adjacents ont été délimitées et cartographiées y compris les arbres voisins, qui ont été identifiés à des espèces. Des points de coordonnées cartésiennes ont été attribués et enregistrés pour chaque arbre. De plus, la surface horizontale de la couronne a été estimée pour chaque arbre en mesurant la projection de la couronne au niveau du sol. L'ouverture de la canopée et le pourcentage de lumière transmis à travers la canopée ont été estimés en analysant des photographies hémisphériques. Les fourmis ont été collectées pendant deux cycles de culture consécutifs par une technique de Chemical Knock Down. La loi binomiale négative et des semivariogrammes ont été utilisés pour définir la distnbution des populations de fourmis. Ensuite, une Pondération inverse à la distance a été utilisée pour des cartes d'interpolation destinées à localiser des colonies éparses. Les résultats montrent que les populations des espèces dominantes comme Oecophyllalonginoda, Tetramoriumaculeatum, Crematogastergabonensis, C. clariventriset C. striatula étaient généralement regroupées et présentaient une forte dépendance spatiale. Camponotus acvapimensis qui est une espèces sous-dominante commune dans la plupart des agrosystèmes à base de cacaoyers était répartie de façon aléatoire et suivait un effet de pépite pur et simple d'un point de vue spatial. Les cartes d'interpolation spatiale ont montré de fortes corrélations entre des densités élevées de populations de O. longinoda et de Caacvapimensis et des zones de luminosité élevée dans les exploitations. À l'opposé, T. aculeatum, C. gabonensis, C. clariventris et C. striatula étaient très regroupées dans les zones ombragées. L'utilisation de certaines espèces comme O. longinoda and T. aculeatuin comme agents de lutte biologique pour la protection des cultures doit prendre en compte l'influence de ces facteurs pour favoriser l'expansion des colonies dans les exploitations cacaoyères.
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2009

2009Autre
Diversity and mosaic structure of ant (Hymenoptera: Formicidae) community in traditional cocoa agroforestry systems in southern Cameroon
Zéphirin Tadu, Champlain Djiéto‐Lordon, Abraham Fomena, Régis Babin, G. Mahiane, Yédé
Agritrop (Cirad)
In cocoa agrosforestry systems, ants are the major arthropod component of the canopy. Since dominant ant species are usually active predators of insects. Ant community may contribute to protect cocoa against insect pests, and especially from cocoa mirids. On the other hand, ant activities may be involved in disease epidemics, and then lead to significant crop losses. In Cameroon, little information is available on ant community in cocoa agroforests and on their contribution to cocoa health. Therefore, the main objective of this study was to characterize the ant mosaic in cocoa farms by assessing the diversity of ant species, the nature of ant associations and their ecological statute. For two consecutive years, we collected ants using a chemical knock-down sampling method, in 21 cocoa plantations, situated in three different agro ecological areas of the center region of Cameroon. The ant diversity was assessed using the species richness, Shannon`s index of diversity and the Sorensen`s similarity index. Kendall`s correlation coefficient was used to determine the association nature between ant species. The robustness of associations was appreciated using chi-square test with Yates corrected test. Fifty one ant species were collected the first year of experimentation and sixty five the second year. Ants of the subfamilies Formicinae and Myrmicinae were the most abundant and the most diverse in cocoa plantations. According to the Shannon`s index of diversity, ant community was less diversified in the plantations located in the savannah compared to those of the forest areas. Oecophylla longinoda, Crematogaster clariventris, Crematogaster striatula and Camponotus acvapimensis were the most abundant species for the first year, with 50.9%, 35.2%, 21.1% and 14.1% individual respectively. The second year, O. longinoda, Tetramorium aculeatum, the army ant Dorylus (Anoma) nigricans and C. striatula were the most abundant, with rates of 82.2%, 44.1%, 39.2% and 29.4% respectively. Among the dominant species, O. longinoda and T. aculeatum are known to be profitable for cocoa. On the other hand, Crematogaster spp. are usually positively associated with aphids, mealybugs and scale insects, and may be involved in epidemics of the black pod rot of cocoa. The use of our results for integrated crop management strategies is discussed. (Texte intégral)
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2024Article de revueAccès ouvert

Susceptibility of Mangifera indica (Sapindales: Anacardiaceae) cultivars to fruit flies (Diptera: Tephritidae) in 2 agroecological zones of Cameroon

Didi Gaëlle Mokam, Ndakabo Atougour, Zéphirin Tadu, Désirée Chantal Aléné, Ezéchiel Awono, Serge Lontsi Tapéo et 2 autre(s)

Journal of Insect Science

The Sudano-Sahelian and the high Guinea savannahs agroecological zones of Cameroon are suitable for the full development of tree crops, including mango. Unfortunately, fresh fruits exported to local and international markets are frequently rejected due to the presence of fruit fly larvae (Diptera: Tephritidae), resulting in drastic income losses and overuse of chemical control products. To promote sustainable management strategies, a 2-yr study (2020-2021) was conducted in 4 and 3 mixed orchards, respectively. Attacked mangoes showing signs of fruit fly damage were collected and taken to the laboratory to rear and identify fruit flies. Repeated grafting and agroclimatic differences were responsible for dissimilarities between the 2 zones, with 18 and 16 cultivars, respectively. From 2,857 attacked mangoes, 26,707 fruit flies belonging to 4 species were identified: Bactrocera dorsalis, Ceratitis cosyra, Ceratitis fasciventris, and Ceratitis anonae. Climate change was the factor determining the distribution of the 2 most important mango fruit flies: B. dorsalis was a wetland species (dominance/occurrence > 70%), while C. cosyra was a dry-land species (dominance/occurrence > 75%). Both species were responsible for high levels of infestations. Bactrocera dorsalis preferred 3 mango cultivars, namely Palmer and Smith in Zone 1, and Ifack 1 in Zone 2 (infestation > 20 individuals/100 g of mango). The host-plant spectrum of C. cosyra was modified by alternative host plants. Both C. fasciventris and C. anonae were rare. Findings from this study could guide researchers in the development of monitoring tools for fruit fly populations and, subsequently, in reducing the damage they cause to mangoes.

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2024Article de revueAccès ouvert

The Influence of Slope Gradient on Termite Assemblages and Soil Physico-Chemical Properties in Koudi Secondary Forest Patches of the Central Region of Cameroon

Akama Pierre Dieudonné, Yédé, Zéphirin Tadu, Elomo Assomo Parfait Thierry, Navodita Maurice

Asian Journal of Environment & Ecology

Soil is the Cameroon’s primary economic driver and an indispensable natural resource for agriculture. Various factors including physical, chemical and biological directly affect agricultural production by enhancing soil fertility. The influence of relief on termites’ diversity was extensively studied. However, the effect of the slope gradient on termite diversity and functional groups remains less studied. This study evaluated termite assemblages in relation to some edaphic parameters, with emphasis on gradual changes in soil slope. The study was conducted in Koudi, in the semi-deciduous forest zone of Southern Cameroon. The study aimed to evaluate the effect of slope gradient on termite diversity and some soil physico-chemical factors; the influence of some physico-chemical soil properties on termites. To achieve these, three slope gradients: gentle slope: A [0 - 15°]; moderate slope: B [15.1°- 31°]; and steeper slope: C [x > 31°[were chosen. The experimental design was composed of 66 rectangular quadrants of 5m x 2m in order to determine the presence or absence of termites. Two soil samples were taken per slope gradient for the determination of physico-chemical parameters. Termite community was characterized using species richness, Shannon diversity, Pielou Evenness and Simpson dominance indexes. Data obtained were subjected to Spearman correlation test and ANOVA followed by the Tukey HSD test at a threshold p = 0.05. Our findings suggested thirty-five(35) termite species belonging to eighteen (18) genders, six (6)subfamilies that were sampled and identified. Termites’ diversity and species richness decreased as slope gradient increased; slope gradient displayed a significant detrimental correlation with sand (%) and total organic (g/kg) content, with a positive significant correlation with clay (%) content, according to Spearman's test. It appeared that variations of slope at soil surface have been identified as one of the factors controlling nutrients and termite diversity.

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2021Article de revue

Prey Fragmentation and Transport in Six Tropical Arboreal Ant Species

Zéphirin Tadu, Messop‐Youbi Edith Blandine, Fomekong Lontchi Judicael, Aléné Desirée Chantal, Champlain Djiéto‐Lordon

Computational Biology and Bioinformatics

Prey fragmentation and transport modalities were studied in Myrmicaria opaciventris, Platythyrea conradti, Cremtogaster sp., Crematogaster clariventris, Tetramorium aculeatum and Oecophylla longinoda, six tropical ant species with varying levels of adaptation to foraging in the tree canopy. Termites and grasshoppers of different sizes were used as prey and deposited on a hunting arena. After prey capture, we investigated the strategy adopted by each ant species to fragment and transport their prey. The data were analyzed with classification tree, using Chi-squared Automatic Interaction Detection method to find the variation in prey fragmentation strategies and transportation modalities between arboreal ant species in relation with prey type and prey size. The results showed that prey fragmentation did not occur systematically after capture and varied between ant species with prey type and prey size. Studied ant species cut their prey either completely into tiny pieces or partially into two or three large pieces before cutting them totally into tiny pieces or not at all. Fragmentation strategy, induced variation in transport modalities including (a) transport of large pieces, each by a single worker; (b) transport of large pieces, each, by a group of workers; (c) transport of tiny pieces after total cutting, and (c) transport of entire prey in the nest without fragmentation. Prey fragmentation and transport modalities varied between ant species in relation with their level of adaptation to arboreal area.

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2020Article de revue

Influence of season on leaf litter ant (Hymenoptera: Formicidae) diversity in the locality of Minko'o (Southern, Cameroon)

Tchoudjin Gertrude Loveline, Zéphirin Tadu, Judicael Fomekong‐Lontchi, Stéphanie Kakam, Syntiche Roselle Aymélé‐Choungmo, Patrick Kenfack‐Fogang et 3 autre(s)

African Journal of Ecology

Abstract Seasonality is known to influence ant activity in many tropical rain forests in the world such as South America and Africa. We surveyed ant fauna in the leaf litter in the locality of Minko'o. The work aimed to evaluate the effect of seasonal variation on the diversity and composition of litter ants. Ants were sampled from November 2015 to June 2017, using four sampling methods: visual capture, bait, pitfall trap and extraction. Species richness, Shannon diversity index and analysis of similarities were used to characterise diversity of ant communities between seasons. We collected 306 ant species, shared out between 56 genera and 11 subfamilies. Subfamilies Myrmicinae, Ponerinae, Dolichoderinae, Formicinae, Dorylinae, Cerapachyinae and Pseudomyrmecinae occurred in all the seasons. Species richness was highest in major dry season with 243 species followed by minor rainy season with 188, major rainy season with 177 species and finally minor dry season that recorded the lowest with 155 species. Kruskal–Wallis test showed that ant species richness did not differ between seasons ( p > 0.05). Species diversity index indicated that diversity was the highest during minor dry season (H′ = 4.24), followed by the major dry season (H′ = 4.23), minor rainy season (H′ = 4.21) and lowest during major rainy season (H′ = 4.06). Eight most frequents ants have been recorded: Axinidris sp.1, Camponotus flavomarginatus , Monomorium guineense , Myrmicaria opaciventris , Odontomachus troglodytes , Carebara perpusilla , Paltothyreus tarsatus and Pheidole megacephala . Assessment of the seasonal effect on diversity reveals that dry season is richer and more diverse than rainy season and the season significantly influence the diversity of litter ants.

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2019Article de revueAccès ouvert

Ant-hemipteran associations in a market-gardening based agro-system in a Yaoundé suburb, Centre Region (Cameroon)

Désirée Chantal Aléné, Désirée Chantal Aléné, Yveline Matchinda Moukem, Zéphirin Tadu, Champlain Djiéto‐Lordon

International Journal of Biological and Chemical Sciences

Tritrophic plant-hemipteran-ant relationships are poorly documented in tropical African market-garden agro-systems despite its agronomic importance. The present study aimed at characterizing ant-hemipteran associations on five market crop species at Nkolondom (north-western suburb of Yaoundé): Abelmoschus esculentus, Capsicum annum, Solanum lycopersicum, Solanum melongena and Solanum scabrum. From July to October 2013, twice per week, feeding activities of ants were examined and the occurrence of each ant/hemipteran association recorded per plant species. As result, ants preferentially harvested honeydew excreted by hemipterans. However, Myrmicaria opaciventris and Camponotus flavomarginatus also collected plant sap from wounded organs. Among hemipterans, Aphis fabae, Aphis gossypii, Aulacorthum solani, Macrosiphum euphobiae, scale insects and mealybugs were the most recurrent. The most frequent associations were M. opaciventris-A. fabae and C. flavomarginatus-A. fabae on S. scabrum, C. flavomarginatus-M. euphorbiae on S. lycopersicum, C. flavomarginatus-A. solani on C. annuum, M. opaciventris-A. gossypii and Technomyrmex sp.-A. gossypii on S. lycopersicum. Some moderately frequent associations viz. C. flavomarginatus-M. euphorbiae and M. opaciventris-M. euphorbiae were recorded on S. melongena. For these associations, highly significant and positive correlations was raised between ants’ and aphids’ populations, suggesting potential mutualistic interactions between the two taxa. Keywords: Aphids, bugs, feeding behavior, Formicidae, interactions, market crops.

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2019Article de revueAccès ouvert

Diversity of hemipterans and ants in a market-gardening based agro-system in a suburb of Yaoundé, Centre Region (Cameroon)

Désirée Chantal Aléné, Yveline Matchinda Moukem, Zéphirin Tadu, Champlain Djiéto-Lordon

International Journal of Biological and Chemical Sciences

Hemipterans are sap sucking insects that may seriously affect their host-plants’ fitness in case of population outbreaks. They are often associated with various ant species that feed on the honeydew they produce. These two insect taxa are highly diversified, but poorly documented in market crop environment of tropical Africa. In order to improve knowledge on these potential pests, they were sampled twice per week on five plant species including Abelmoschus esculentus, Capsicum annuum, Solanum lycopersicum, Solanum melongena and Solanum scabrum in a trap garden settled at Nkolondom, a north-western suburb of Yaoundé, from July to October 2013. As result, the hemipteran community was dominated by aphids (Aphididae), vz Aphis fabae, Aphis gossypii and Aulacorthum solani on S. scabrum, A. esculentus and C. annuum respectively, and Macrosiphum euphobiae on S. melongena and L. esculentum; scale insects and mealybugs (Coccoidea), the whitefly Bemisia tabacci (Aleyrodidae) on C. annuum. Leafhoppers (Cicadelidae) and treehoppers (Membracidae) occurred preferentially on S. melongena and A. esculentum. Some true bugs (Heteroptera), vz Miridae, Pentatomidae, Pyrrhocoridae and Reduviidae were recorded mainly on okra. The ant community was mostly represented by honeydew feeding species among which Myrmicaria opaciventris, Camponotus flavomarginatus, Pheidole megacephala and Technomyrmex sp. Keywords: Sap sucking insects, aphids, Formicidae, market crops, inventory. English Title: Diversité des hémiptères et des fourmis dans un agrosystème à base de cultures maraîchères dans une banlieue de Yaoundé, Région du Centre (Cameroun)Les hémiptères sont des insectes suceurs de sève capables d’affecter sérieusement le fitness de leurs plantes hôtes en cas de fortes pullulations. Ils sont souvent associés avec diverses espèces de fourmi qui se nourrissent du miellat qu’ils produisent. Ces taxa sont très diversifiés, mais faiblement étudiés en milieu maraîcher en Afrique tropicale. Dans le but d’améliorer les connaissances sur ces potentiels ravageurs, ils ont été échantillonnés deux fois par semaine sur cinq espèces de plantes dont Abelmoschus esculentus, Capsicum annuum, Solanum lycopersicum, Solanum melongena et Solanum scabrum dans un jardin expérimental à Nkolondom, périphérie nord-ouest de Yaoundé, entre Juillet et Octobre 2013. Comme résultat, la communauté des hémiptères était dominée par les pucerons (Aphididae), Aphis fabae, Aphis gossypii et Aulacorthum solani sur S. scabrum, A. esculentus et C. annuum respectivement, et Macrosiphum euphobiae sur S. melongena et S. lycopersicum ; des cochenilles (Coccidae et Pseudococcidae) et la mouche blanche Bemisia tabacci (Aleyrodidae) ont été trouvés sur C. annuum ; des Membracidae et des Cicadelidae ont préférentiellement été trouvés sur S. melongena et A. esculentum quelques hétéroptères (Miridae, Pentatomidae, Pyrrhocoridae et Reduviidae) ont principalement été observés sur le gombo. La communauté de fourmi comprenait surtout des espèces mielliphages telles Myrmicaria opaciventris, Camponotus flavomarginatus, Pheidole megacephala et Technomyrmex sp. Mots clés : Insectes suceurs de sèves, pucerons, Formicidae, cultures maraîchères, inventaire.

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2012Article de revue

Les possibles rôles d'Oecophylla Longinoda (Latreille) et Tetramorium Aculeatum (Mayr) dans la lutte biologique contre les mirides du cacaoyer au Cameroun

Yédé, Gerben Martijn Ten Hoopen, Régis Babin, Zéphirin Tadu, Raymond Joseph Mahob, Wilfrid Nana et 1 autre(s)

Etant donne l'incidence de la maladie du cacaoyer appelee la maladie des balais de sorcieres, a Bahia, au Bresil, des materiels resistants dotes d'une productivite elevee et de caracteristiques physiques superieures ont ete selectionnes par le programme de selection nationale et par les cacaoculteurs de la region. Afin de selectionner des varietes prometteuses egalement dotees d'une bonne qualite sensorielle, cet etude visait a evaluer le profil sensoriel de 23 varietes de cacaoyers par trois panels differents: (1) CIRAD (CIR), CEDEX, Montpellier, France (evaluation de liqueur de cacao); (2) Chocolat Valrhona (V AL) Tain-l'Hermitage-France (evaluation de chocolat); (3) Faculte de Genie alimentaire/UNICAMP (UNI), Campinas, Bresil (evaluation de chocolat). Les cabosses de chaque variete ont ete collectees pendant la meme periode de recolte (octobre 2010 a janvier 2011) et ont ete soumises aux memes processus, de la recolte a la fin de l'etape de sechage, par M. Libânio Agricola S.A (Gandu/Bahia/Bresil). Chaque groupe responsable du panel sensoriel a produit et realise l'evaluation sensorielle d'echantilons conformement a des protocoles internes, en utilisant exclusivement les memes termes descriptifs et une echelle de notation sur 9 points ancres non structures: 1 = tres faible ou absent(e) a 9 = fort(e), en evaluant les attnbuts suivants: arome, acidite, amertume, astringence, douceur, caramel/miel, chocolat, floral et fruits secs. Les resultats ont ete analyses statistiquement au travers d'essais ANOV A et MANOV A et avec la methode de correlation de Pearson. En general, on a observe une correlation entre les panels qui ont evalue le chocolat (VAL et UNI, les attnbuts d'acidite, d'amertume et de gout sucre) et aucune correlation entre ces panels et le panel du CIR, qui ont evalue la liqueur. L'evaluation de l'interaction entre les laboratoires (VAL et UNI) et les varietes etait significative pour tous les attributs des echantillons de chocolat L'evaluation des differences entre les varietes pour tous les attributs sensoriels analyses ensemble (Lambda de Wilks) a montre que les varietes: CCN10, EET397, PH129, VB515 et TSAN792 etaient differentes de toutes les autres (p <0.001%). Concernant les attributs de l'arome: caramel/miel, chocolat et fruits secs, on n'a observe aucune difference significative entre les echantilons (analyse unidimensionnelle). la variete EET397 a obtenu la note la plus elevee pour l'arome floral, eclipsant ainsi toutes les autres sauf la variete TSAN792. D'autre part, les varietes PH129, FA13 et CA1.4 ont obtenu les notes les plus elevees pour l'acidite, l'amertume et l'astringence. Il est donc possible de conclure qu'il existe une grande difference entre l'arome des differents echantillons, ce qui est confirme par le profil sensoriel de la liqueur et du chocolat obtenus par les trois panels sensoriels. Au cours des prochaines etapes de cette etude, on evaluera la composition chimique et l'influence de la periode de recolte sur les caracteristiques sensorielles, afin de definir le potentiel de qualite de chaque materiel teste. (Resume d'auteur)

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2009Autre

Influence of insecticide treatment on ant diversity in tropical agroforest system: The case of Cameroonian cocoa farms

Zéphirin Tadu, Champlain Djiéto‐Lordon, Abraham Fomena, Régis Babin, Yédé, G. Mahiane

Agritrop (Cirad)

In order to understand the influence of anthropogenic disturbance on ant communities in tropical region; we conducted a study in southern Cameroonian cocoa farm. The survey aim to assess the influence of phytosanitary treatment on ant diversity and recolonization process of cocoa farm by ant species. During two consecutive years 2006-2007 and 2007-2008 ants sampling was performed using Chemical Knock-down technique in six traditional cocoa farms located in tree localities under different agro ecological environmental condition. Ant diversity was assessing using Shannon index of diversity and Sorensen index of similarity. After treatment: (1) the most abundant and most diverse sub-families were Formicinae and Myrmicinae; (2) at a local scale, with a small exception, specific richness of ant increase in plantations whereas diversity decrease; (3) at a regional scale, the specific richness increase and remain high both in forest (S= 46) and transitional (S= 46) areas compare to savannah (S= 42); diversity increase in transitional area whereas in forest and savannah diversities slide; (4) we have collected 10, 13 and 26 news ant species respectively in Bokito, Obala and Ngomedzap. Among the news establish species, Dorylus (Anoma) nigricans (Illiger) workers collected at Ngomedzap were the most abundant (36,36 %) and most frequent (53 %) on the tree; whereas among formerly establish species Oecophylla longinoda (Latreille) and Crematogaster gabonensis (Mary) were the most abundant respectively in Bokito (55,63 %) and Obala (31,48 %). Our result suggests formally that Phytosanitary treatment may affect ant diversity and favorise the establishment of some species like army ant D. (Anoma) nigricans (I.). In spite of the treatment certain ant species like O. longinoda (L.) and some species belonged to Crematogaster genus according to their nesting behavior may resist against treatment. This Knowledge may help to develop an integrate pest management program combine benefic ant species and selective insecticide spraying to protect tropical crops against scale insect. (Texte intégral)

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2009Livre

Rapport scientifique et technique, juillet 2006-novembre 2007. REPARAC - Projet de recherche en partenariat N°5 (PRP Cacao) : Contribution à la diversification et à la gestion durable des systèmes de culture à base de cacaoyers

Patrick Jagoret, Régis Babin, Lucien Bidzanga Nomo, M. Mbenoun, Raymond Bourgoing, Crescence Virginie Mfegue et 2 autre(s)

Agritrop (Cirad)

L'objectif du PRP Cacao est de contribuer à la gestion durable des systèmes de cacaoculture du Centre Cameroun en proposant aux exploitants des alternatives techniques économiquement viables qui soient mises au point de façon participative et qui permettent une amélioration significative de la productivité et de la rentabilité des vergers de cacaoyers. Au cours de la période, les travaux de recherche du PRP Cacao, qui s'inscrivent dans l'axe 1 du projet REPARAC intitulé "Dynamique des exploitations et durabilité des systèmes de production", ont été réalisés sans difficultés particulières. Les activités ont principalement concerné (i) la consolidation du fonctionnement du collectif du PRP Cacao qui regroupe 21 personnes, (ii) le renforcement du partenariat déjà existant avec le monde rural et la construction d'un partenariat avec le monde scientifique, (iii) la mise en place d'un dispositif de recherche et de co-construction d'innovations répondant aux exigences des questions de recherche posées par le collectif, (iv) la caractérisation des systèmes de cacaoculture existants à travers l'étude des populations de cacaoyers et celle des bio-agresseurs et (v) le transfert de plusieurs innovations en milieu réel. Outre les différents rapports trimestriels et semestriels d'activités et autres documents demandés par la cellule de coordination du REPARAC, le collectif du PRP Cacao a rédigé une synthèse bibliographique non exhaustive de 181 références qui a permis de faire le point des connaissances disponibles sur la problématique étudiée. Le collectif a par ailleurs encadré quatre étudiants issus des universités de Dschang et de Yaoundé 1 et dans le même temps, plusieurs membres du collectif ont suivi diverses formations organisées notamment par la cellule de coordination du REPARAC. Sur le plan budgétaire, le taux de consommation du budget du PRP Cacao est de 85% au 1er novembre 2007, les principaux postes de dépenses étant le personnel temporaire, les indemnités de mission, le carburant et les consommables.

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ZEPHIRIN TADU

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