PHASAL STATE OF SCHISTOCERCA GREGARIA FORSKAL, 1775 (ORTHOPTERA, ACRIDIDAE) IN THE BREEDING BIOTOPES OF ALGERIAN SAHARA DURING 2009 AND 2010

Abstract

To better understand the trend of locust populations existing in southern Algeria during the calm periods (recession), a study on the phase status of locust populations of Schistocerca gregaria in its natural biotope, was carried out during the two years 2009 and 2010. To do this, morphometric measurements of 163 Locust individuals including 81 males and 82 females, from eight different biotopes, were performed. The mean values of morphometric ratios of Elytron on Femur (E / F) and Femur on Cephalic capsule (F / C) in the 8 study sites fluctuate in males from 2.02 to 2.13 for the E / F ratio and 3 65 to 3.95 F / C ratio. For females E / F varies between 2.09 to 2.15 and F / C varies between 3.83 to 4.03. The comparison of the results related to E / F ratios and F / C with those of Dirsh (1953) and the report on their morphometric abacus of Duranton and Lecoq (1990) showed that male and female populations that evolve in the biotopes of both southern and central parts of the Algerian Sahara, for the two years 2009/2010 are mostly the Solitarious-transient with a rare presence of purely solitary individuals and a total absence of gregarious individuals.