Taxonomie et diversité du genre Gryllotalpa (Orthoptera : Gryllotalpidae)dans trois zones agro-écologiques de la partie sud du Cameroun.

Abstract

Mole crickets form one of the most distinctive groups of Orthoptera as they are the only true burrowers. They are known to be serious crop pests because of their feeding on the root system. Although they are crop pests, some species are of conservation interest. Literature on mole crickets is almost non-existent on Cameroonian fauna and its diversity unknown. It is with a view to fill these gaps that we have carried out this work, the main objective of which is to assess the impact of the transformation of the plant cover on the diversity of mole crickets in three agro-ecological zones in the southern part of Cameroon. The field studies was carried out from March 2016 to March 2018 in nine localities (Bangangté, Mbouda, Bafoussam, Buea, Kumba, Tombel, Talba, Mfou, Balamba). In each locality, four plant formations, namely a forest, an agro-forest, a fallow land, and a crop field, were surveyed. In each plant formation, the species were collected by the method of the pitfalls. These surveys made it possible to collect 192 individuals of the genus Gryllotalpa, belonging to 12 species of the parva and africana groups. Among the species listed, one (01) is reported for the first time in Cameroon (Gryllotalpa microptera) and six (06) are new to science, in particular : Gryllotalpa cameroonensis sp. nov., Gryllotalpa mboudaensis sp. nov., Gryllotalpa tamessei sp. nov., Gryllotalpa weisei sp. nov., Gryllotalpa babetensis sp. nov., and Gryllotalpa tombelensis sp. nov.. The descriptions were accompanied by an identification key for the species in each group. The diversity of mole crickets varied greatly between different agro-ecological zones, localities, types of vegetation, seasons and according to soil characteristics. Overall, the transformation of the plant cover and the physicochemical characteristics of the soils are factors of variation in the biodiversity of mole crickets. Thus, the diversity and abundance of mole crickets were jointly higher in the ZHP, the locality of Babeté, in crop fields, and in the rainy season. On the other hand, they were weaker or almost nil in the ZFPB, in the forest localities of Mfou, Talba and Balamba. The affinity of mole crickets with the physico-chemical characteristics of the soilvaried more or less depending on the species of the genus Gryllotalpa.