Prévalence et abondance de Charletonia cameroonensis Haitlinger & Kekeunou 2014 (Acari : Erythraeidae) parasite de Zonocerus variegatus (Linnaeus 1758) (Orthoptera : Pyrgomorphidae) dans la zone côtière du Cameroun

Objectifs: La recherche d’une stratégie de protection des cultures vivrières contre le criquet ravageur Zonocerus variegatus (Linnaeus 1758) (Orthoptera : Pyrgomorphidae) a consisté à étudier chez cet hôte, la prévalence et l’abondance de Charletonia cameroonensis Haitlinger & Kekeunou 2014 (Acari : Erythraeidae) dans la zone côtière du Cameroun.Méthodologie et résultats: Les captures et observations ont été menées hebdomadairement d’avril 2013 à avril 2014 à Logbessou, un quartier de la banlieue Nord-est de la ville de Douala. Pendant une heure (8h30-9h30), les individus de Z. variegatus ont été capturés et C. cameroonensis a été énuméré sur tout le corps de chacun. Il apparait que C. cameroonensis est un ectoparasite permanent de Z. variegatus, puisqu’il a été rencontré durant toute la période d’étude et sur la quasi-totalité des stades postembryonnaires. Sa prévalence a atteint 21,40 %. Le pourcentage d’infestation a significativement augmenté du stade larvaire 1 (4,14%) au stade adulte (67,58%). Ce pourcentage d’infestation a été plus élevé en saison pluvieuse (31,02%) qu’en saison sèche (7,69%). L’abondance de C. cameroonensis a varié de 0 à 23 individus parasites par individu de Z. variegatus. Cette abondance s’est accrue du stade larvaire1 au stade adulte. C. cameroonensis a été présent sur les trois tagmes de Z. variegatus, avec une charge significativement plus élevée sur le thorax et principalement au niveau des ailes. Une corrélation significativement positive a été obtenue entre l’abondance du parasite et la taille des populations du ravageur.Conclusions et application des résultats: Ces résultats préliminaires apportent des connaissances qui pourraient être approfondies dans le cadre d’études ultérieures pour une exploitation de C. cameroonensis dans une optique de lutte biologique contre Z. variegatus.Mots clés: Abondance, prévalence, C. cameroonensis, Z. variegatus, Zone côtièreEnglish AbstractObjectives: The search for a strategy to protect food crops against Zonocerus variegatus (Linnaeus 1758) (Orthoptera : Pyrgomorphidae) was to investigate the prevalence and abundance of Charletonia cameroonensis Haitlinger & Kekeunou 2014 (Acari : Erythraeidae) in the coastal area of Cameroon.Methodology and results: Catches and observations were conducted weekly from April 2013 to April 2014 in Logbessou, a sub-urban North-East of Douala. For one hour (8:30 to 9:30), individuals of Z. variegatus (all stages combined) were captured and the distribution of C. cameroonensis on each insect was recorded. It appears that C. cameroonensis was a permanent parasite of Z. variegatus. Parasite prevalence reached 21.40 %; this prevalence increased significantly from the stage 1 larva population (4.14%) to adult stage (67.58%). Parasite prevalence was higher during the rainy season (31.02%) than during the dry season (7.69%). C. cameroonensis abundance varied from 0-23 (averagely 0.54±1.65 parasites per host). This abundance also increased significantly from stage 1 larva (0.05±0.24 parasites per host) to adult (2.36±3.4 parasites per individual host). C. cameroonensis was present on the three body regions of the host, with a significantly greater parasite load on the thorax and more precisely on the wings. A significantly and positive correlation has been established between the parasite abundance and the size of Z. variegatus population.Conclusion and application of results: These preliminaries results provides important information that could be explored in future studies in the context of biological control of Z. variegatus by C. cameroonensis.Keywords: Abundance, prevalence, C. cameroonensis, Z. variegatus, Coastal zon

Shrews (Mammalia, Eulipotyphla) from a biodiversity hotspot, Mount Nimba (West Africa), with a field identification key to species

In this study, we collected 226 shrew specimens originating from 16 localities on the Guinean and Liberian sides of Mount Nimba. We surveyed all major vegetation zones from 400 to 1600 m above sea level (asl), including forest and savannah habitats. We recorded 11 species, whose identifications were confirmed by genetic analyses and classical morphometrics. Furthermore, we provide cytogenetic data for five of these species. The shrew community at Mount Nimba is composed of a mix of both savannah- and forest-dependent species, which is related to the peculiar position of Mount Nimba situated at the transition between lowland rainforest to the south and Guinean woodlands to the north. We recorded 11 species of shrews in syntopy in lowland rainforest, seven in edaphic savannah and mountain forest, and five in high-altitude savannah at 1600 m asl. Based on morphometric analyses, we show that these syntopic species separate along a size axis, allowing species to occupy different ecological niches, which we speculate allows them to access different food resources. We also highlight that Crocidura theresae Heim de Balsac, 1968 from Mount Nimba has a different karyotype from that described in Côte d’Ivoire. Finally, we develop a novel identification key for shrews from Mount Nimba using external characters and standard body measurements, allowing it to be used in the field on live specimens. In total 12 shrew species are now known from Mount Nimba, which highlights its exceptional position as a tropical African biodiversity hotspot.https://sciencepress.mnhn.fr/en/periodiques/zoosystemadm2022Mammal Research InstituteZoology and Entomolog

Assessment of Three Mitochondrial Genes (16S, Cytb, CO1) for Identifying Species in the Praomyini Tribe (Rodentia: Muridae)

The Praomyini tribe is one of the most diverse and abundant groups of Old World rodents. Several species are known to be involved in crop damage and in the epidemiology of several human and cattle diseases. Due to the existence of sibling species their identification is often problematic. Thus an easy, fast and accurate species identification tool is needed for non-systematicians to correctly identify Praomyini species. In this study we compare the usefulness of three genes (16S, Cytb, CO1) for identifying species of this tribe. A total of 426 specimens representing 40 species (sampled across their geographical range) were sequenced for the three genes. Nearly all of the species included in our study are monophyletic in the neighbour joining trees. The degree of intra-specific variability tends to be lower than the divergence between species, but no barcoding gap is detected. The success rate of the statistical methods of species identification is excellent (up to 99% or 100% for statistical supervised classification methods as the k-Nearest Neighbour or Random Forest). The 16S gene is 2.5 less variable than the Cytb and CO1 genes. As a result its discriminatory power is smaller. To sum up, our results suggest that using DNA markers for identifying species in the Praomyini tribe is a largely valid approach, and that the CO1 and Cytb genes are better DNA markers than the 16S gene. Our results confirm the usefulness of statistical methods such as the Random Forest and the 1-NN methods to assign a sequence to a species, even when the number of species is relatively large. Based on our NJ trees and the distribution of all intraspecific and interspecific pairwise nucleotide distances, we highlight the presence of several potentially new species within the Praomyini tribe that should be subject to corroboration assessments

Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

The bii4africa dataset of faunal and floral population intactness estimates across Africa’s major land uses

Sub-Saharan Africa is under-represented in global biodiversity datasets, particularly regarding the impact of land use on species’ population abundances. Drawing on recent advances in expert elicitation to ensure data consistency, 200 experts were convened using a modified-Delphi process to estimate ‘intactness scores’: the remaining proportion of an ‘intact’ reference population of a species group in a particular land use, on a scale from 0 (no remaining individuals) to 1 (same abundance as the reference) and, in rare cases, to 2 (populations that thrive in human-modified landscapes). The resulting bii4africa dataset contains intactness scores representing terrestrial vertebrates (tetrapods: ±5,400 amphibians, reptiles, birds, mammals) and vascular plants (±45,000 forbs, graminoids, trees, shrubs) in sub-Saharan Africa across the region’s major land uses (urban, cropland, rangeland, plantation, protected, etc.) and intensities (e.g., large-scale vs smallholder cropland). This dataset was co-produced as part of the Biodiversity Intactness Index for Africa Project. Additional uses include assessing ecosystem condition; rectifying geographic/ taxonomic biases in global biodiversity indicators and maps; and informing the Red List of Ecosystems

Systématique et biogéographie des rongeurs des forêts de la ligne volcanique du Cameroun (Afrique Ouest centrale)

Les forêts de la Ligne Volcanique du Cameroun (LVC) font partie du point chaud de biodiversité guineo-congolais et ont été identifiées parmi les zones prioritaires de conservation dans le monde. Cet axe volcano-tectonique, qui s est mis en place à partir du Crétacé supérieur, est une cordille re qui coupe le bloc forestier afro-tropical à la limite Ouest de l Afrique centrale. Connue pour sa faune et sa flore originale (endémisme et forte richesse spécifique), la LVC constitue une région de choix pour tester les mécanismes de diversification de la faune des régions tropicales de plaine et de montagne. La comparaison des patrons de diversification obtenus pour plusieurs taxons devrait nous permettre d identifier les évènements principaux qui ont structuré la biodiversité en Afrique centrale. Nous avons mené une analyse phylogéographique afin d expliquer la distribution et la richesse (générique, spécifique et intraspécifique) actuellement observées sur la LVC. Lors de cette thèse nous avons choisi de nous focaliser sur les rongeurs. Ce groupe représente, de par le nombre d espèces décrites, la part la plus importante de la biodiversité des mammifères. Plusieurs espèces ont été signalées comme étant endémiques de la LVC. De plus les rongeurs sont reconnus comme étant d excellents modèles biologiques pour les études de phylogéographie. Les genres Lamottemys, Praomys, Hybomys, Hylomyscus et Lophuromys ont été retenus pour nos analyses. Nous avons combiné des données morphologiques et moléculaires pour tester la validité et déterminer la position phylogénétique de plusieurs espèces décrites comme endémiques de la LVC. Nous avons par ailleurs confronté les patrons phylogéographiques obtenus sur quatre espèces (P. jacksoni, P. misonnei, L. eisentrauti, H. rufocanus) afin de proposer un modèle de structuration de la biodiversité sur la LVC. Nos résultats ont été replacés dans un contexte temporel sur la base des datations moléculaires et ont été mis en relation avec les évènements paléo-géo-climatiques connus de l Afrique tropicale et/ou de la LVC en particulier. Nous confirmons le statut spécifique de 5 espèces (Lamottemys okuensis, Praomys hartwigi, Praomys morio, Hybomys rufocanus et Lophuromys eisentrauti) parmi les 9 testées. H. r. eisentrauti, H. r. badius et L. e. roseveari devraient être considérées comme des formes géographiques distinctes au sein de H. rufocanus et de L. eisentrauti respectivement. Des analyses supplémentaires sur P. obscurus doivent être réalisées pour confirmer sa position taxinomique. L endémisme sur la LVC a été essentiellement retrouvé chez les taxa habitant l étage submontagnard et afromontagnard. La faune actuelle de rongeurs de cette région est le résultat de la diversité de ses milieux qui augmente son potentiel biotique. C est également le résultat de trois facteurs historiques : les évènements volcanotectoniques, les fluctuations climatiques du Pléistocène et le rôle des barrières fluviales. Au début du Pliocène, la mise en place de la faune sur la LVC a été influencée par la reprise des activités volcanotectoniques dans cette cordillère et sur le Rift Est africain. Plusieurs cas de divergences récentes traduisent des diversifications allopatriques favorisées par les oscillations climatiques du Pléistocène entre les montagnes de la LVC ou entre ces montagnes et les plaines avoisinantes. Enfin, nous avons discuté de l influence de la Sanaga et d autres fleuves (Ogooue et Ivindo) comme facteur explicatif des patrons phylogéographiques obtenus en Afrique Ouest centrale. Deux sous régions biogéographiques peuvent être identifiées sur la LVC entre Bioko et le Tchabal Mbabo. Leur limite semble se situer entre le mont Lefo et le mont Oku. Il ressort en outre de ce travail que la LVC n a constitué une barrière effective entre l Ouest et l Est de l Afrique tropicale que récemment.The forests of the Cameroon Volcanic Line (CVL) belong to the guineo-congolese biodiversity hotspot and have been identified as one of the principal priority zones for conservation in the world. The topographical complexity of this region, quite unusual in the African humid-forest zone, has led also to climatic and edaphic diversity. Existing data demonstrate the region s high levels of diversity and endemism for several relatively well-known groups. Patterns of differentiation across multiple lineages in the Cameroon volcanic line (CVL) should allow us to identify the main events that have structured biological diversity in the history of afro-tropical forests. We focus our study on rodents. This group represent the most specious of mammals and is particularly diversified in the CVL (with several endemic species). Moreover, rodents are known to be good biological models for phylogeographical studies. The genera Lamottemys, Praomys, Hybomys, Hylomyscus and Lophuromys were retained for this PhD thesis. We combined morphological and molecular approaches to assess the taxonomical validity of several species previously identified as endemic to the CVL and to infer their phylogenetic affinities. Moreover, we performed detailed phylogeographical studies on four species (P. jacksoni, P. misonnei, L. eisentrauti, H. rufocanus) to propose a model of structuration of the CVL biodiversity. We confirm the taxonomical validity of 5 of the 9 tested species (Lamottemys okuensis, Praomys hartwigi, Praomys morio, Hybomys rufocanus and Lophuromys eisentrauti). H. eisentrauti. H. badius and L. roseveari should be considered as geographical forms within the species H. rufocanus and L. eisentrauti, respectively. Additional analyses on P. obscurus should be carried out to confirm its status. CVL endemism mainly concerns submontane and afromontane species. The high rodent biodiversity in this region is maintained by the high diversity of habitats. Several historical factors explain the rodent diversification in this region: the volcano-tectonic activities, the climatic fluctuations of the Pleistocene and the presence of several rivers acting as geographical barriers to gene flow. At the beginning of the Pliocene, strong volcanic activities occurred in eastern Africa (Rift system) and in the CVL, which could have played a major role in favouring speciation events. Several divergent events dated from the Pleistocene were recorded in the CVL. It is likely that periodic climatic fluctuation in the region during the Pleistocene has been marked by the alternate expansion and contraction of montane and lowland-forest biotas. Individual species may have been restricted to refugia (whose location, number and size depended on the ecological tolerance of the species in question), leading to allopatric diversification of rodents. Finally we discuss the role of the Sanaga, Ogooue and Ivindo rivers in promoting or maintaining the diversification of rodents in West Central Africa. Two geographical sub-regions can be distinguished in the CVL: one grouping all the mountains from Bioko to mount Lefo, and another one grouping all the mountains from mount Oku to Tchabal Mbabo. According to our data, it seems likely that the CVL has constituted only recently a barrier preventing East-West exchange of lowland faunas.PARIS-Museum Hist.Naturelle (751052304) / SudocSudocFranceF

West-Central African Pleistocene lowland forest evolution revealed by the phylogeography of Misonne's soft-furred mouse

International audienceWe studied the phylogeographical structure of Praomys misonnei (Rodentia: Muridae) in west-Central Africa based on 113 individuals from 31 localities and the sequencing of two mitochondrial genes (Cytb and CO1). Two clades can be identified through maximum likelihood, bayesian and network analyses: the first one is limited to the Korup National Park, while the second one has a broad geographical distribution in west-Central Africa. The second clade can be further divided into three sub-clades. The results of neutrality tests and mismatch distributionsindicate that a population expansion occurred in these sub-clades. During the middle or upper Pleistocene, the west-Central African populations of P. misonnei may have been isolated in four different forest refugia, followed by population expansion and secondary contact during more humid periods. High genetic diversity was observed in the region of the Bakossi highlands, and the Cameroon Volcanic Line limits the geographical distribution of clades. Thus it seems likely that this volcanic line has in the past constituted a barrier that prevented the east–west exchange between P. misonnei populations through the expansion of the montane forest habitat. Our results also highlight the role of the Sanaga and Ogooué-Ivindo rivers in shaping P. misonnei genetic structure

West-Central African Pleistocene lowland forest evolution revealed by the phylogeography of Misonne’s soft-furred mouse

We studied the phylogeographical structure of Praomys misonnei (Rodentia: Muridae) in west-Central Africa based on 113 individuals from 31 localities and the sequencing of two mitochondrial genes (Cytb and CO1). Two clades can be identified through maximum likelihood, bayesian and network analyses: the first one is limited to the Korup National Park, while the second one has a broad geographical distribution in west-Central Africa. The second clade can be further divided into three sub-clades. The results of neutrality tests and mismatch distributions indicate that a population expansion occurred in these sub-clades. During the middle or upper Pleistocene, the west-Central African populations of P. misonnei may have been isolated in four different forest refugia, followed by population expansion and secondary contact during more humid periods. High genetic diversity was observed in the region of the Bakossi highlands, and the Cameroon Volcanic Line limits the geographical distribution of clades. Thus it seems likely that this volcanic line has in the past constituted a barrier that prevented the east–west exchange between P. misonnei populations through the expansion of the montane forest habitat. Our results also highlight the role of the Sanaga and Ogooué-Ivindo rivers in shaping P. misonnei genetic structure.Key words: Africa, forest refugia, mammal, phylogeography, river