ORTHOPTEROLOGIC FAUNA OF OUARGLA OASIS

Abstract

Orthopterologic populating study has been conducted in 3 stations of Ouargla Oasis situated in south-west of Algeria. Orthopteras Samplings are realized every fortnight from September 2001 until August 2002. This inventory is completed by floristic statements for each station. 18 orthopteras species were inventoried with 16 Caeliferae where 14 belong to family of Acrididaes and so 2 species of Ensiferae belonging to Gryllidae family. Study of total and middle richness shows variation according to stations and to samplings periods. The most important yearly centesimal frequency is pronounced for Pyrgomorpha cognata specie in both palm groves, and for Acrotylus patruelis specie in the cultivated ground of Experimental farm. of Hassi Ben Abdullah. Constancy of Orthopterologic species varies from station to another. However, two species are constant for the three stations, which are Pyrgomorpha cognata and Ochrilidia gracilis. The most important diversity index is 1.66 bits in June month for Mekhadma station. Equitability values are all closer of 1. corresponding to populations in balance between them. The contagious distribution of individuals is the most characteristic. Through factorial analysis of correspondences, we have noted that orthopterologic species are spreading according to their ecologic affinities