No abstract

Fascioliasis and bilharzia occur in the Littoral region of Cameroon. Recent reports indicate a high prevalence of bilharzia in school-age children in the locality of Njombé-Penja, close to the city of Douala. This infectious disease may spread in the near future to the city of Douala, especially if the localities at risk are visited by infected people, who defecate or urinate in streams or swamps as is the habit of populations in populous zones of the city and where environmental cleanliness is not respected. It is known that several molluscs are intermediate hosts of the infectious agents of this pathology but little is known about the snail’s community structure at the coastal zone of the country. The present study aimed to establish a baseline of information on the distribution of snails in the urban environments of the Douala coastal Littoral-zone, as a first step in evaluating the status and the occurrence level of snails known as intermediate hosts of schistosomiasis and distomatosis agents. Seventy-three sample units where inspected from July to November 2020 in eight quarters of the Douala city, using 49 non-contiguous transects 5x40 m² each along streams and 24 non-contiguous quadrates 10x10 m² each around swamps. A total of 4,068 snail’s shelter belonged to 9 families: 3(33.3%) and 6 (66.7%) families for land and freshwater snails respectively. Specimens belonged to 14 genera [6 (42.9%) and 8 (57.1%) genera for land and freshwater snails respectively], and 30 species [14 (46.7%) and 16 (53.3%) species for land and freshwater snails respectively]. Land snails were most diverse [E(Sn=151) = 14 ± 0 species] than freshwater snails [E(Sn=151) = 11 ± 1 species]. Economically important species were highly represented in land snails (30.3%) and lowly represented in freshwater snails (6.1%). Between land snails Achatina and Archachatina (invasive pests for agriculture) were highly recorded in Bépanda-Sic-Cacao, Makepé-Missoké and PK10-Plateau quarters while between freshwater snails known as obligate intermediate hosts for fascioliasis and bilharzia agents, Lymnaea was recorded in Bépanda-Sic-Cacao, Nkomba and Mbanga-Pongo quarters while Biomphalaria occurred exclusively in PK10-Plateau quarter. The community exhibited low evenness, low species richness, low species diversity and low dominance by a few species. The theoretical lognormal model fitted the species abundance distributions and species exhibited a positive association (Schluter’s ratio VR = 6.69, statistic W = 53.49, df = 8, p<0.001 for land snails; VR = 2.27, W = 18.18, df = 8, p = 0.020 for freshwater snails; VR = 4.17, W = 33.42, p<0.001 for the pooled data). Low dominance by a few species indicated that study sites were slightly influenced by interspecific competition and/or disturbance by human activities.

The Littoral Region of Cameroon is one of the most highly disturbed regions in Cameroon that remain poorly studied and where no investigation regarding the grasshopper fauna has been conducted. Hence a survey was conducted from August 2015 to November 2018 in 11 localities of this region. In each locality, grasshoppers were sampled in three vegetation types (forests, fallows and cultivated farms) using sweep nets sampling method. We collected in total 51 short-horned grasshopper species belonging to the families Acrididae, Chorotypidae, Euschmidtiidae, Pyrgomorphidae and Thericleidae. Among these species, 43 belong to Acrididae, 5 to Pyrgomorphidae and only one belongs to the Chorotypidae, Euschmidtiidae and Thericleidae respectively. The Chorotypidae species Hemierianthus mbongueensis Yetchom & Xu sp.nov. is also described in this study. Twelve grasshopper species were widely distributed as they occurred in all study sites and 11 were recorded exclusively from one study site. This study showed that there is high species richness of short-horned grasshoppers in the Littoral Region of Cameroon. However, more sampling effort in different ecosystems of this region and other regions of Cameroon will certainly improve our understanding on grasshopper taxonomy, ecology and biogeography.

The specimens studied were collected with sweep net and pitfall in the forests, agro-forests, herbaceous fallows, and crop fields of 14 localities in the southern part of Cameroon, from August 2015 to February 2018. The results show that Heteracris hannai sp. nov. and Heteracris lecoqi sp. nov. differ from previously known species of the same genus by the pattern of coloration and the details or shape of the phallic complex. H. lecoqi sp. nov. is characterized by light brownish body; male cercus with flattened, downcurved and obtuse apex; lophus strongly curved; interlophal space with V shape; apodeme of cingulum bow, convergent, with V-shape; valve of cingulum in lateral view longer than apical valve of penis; ramus in ventral view joined. H. hannai sp. nov. is distinct to other species by brown to grey body; male cercus with apex rounded, curved inside; lophus curved; interlophal space with U-shape; apodeme of cingulum thick, slightly parallel, with U shape; valve of cingulum in lateral view hardly longer than apical valve of penis; ramus in ventral view opened. The characteristics of H. guineensis are closer to H. hannai sp. nov. than to H. lecoqi sp. nov. H. lecoqi sp. nov. was collected only in the fallows while H. hannai sp. nov. was collected in the forests, agro-forests, fallows, and crop fields. Compared to H. guineensis, both new species are scarce in the natural vegetation and their distribution area is limited to two and four localities respectively for H. lecoqi sp. nov. and H. hannai sp. nov. All these three grasshopper’s species were recorded as accidental species in all types of vegetation.