Seasonal Dimorphism of the Desert Locust in Agricultural Areas in the Sahara

Abstract

The development of Saharan agriculture in recent decades by increasing irrigated areas for vegetable production in central Sahara has led to significant outbreaks of locusts. This insect, which is not a deserticola type, has succeeded in developing a series of behavioural, morphological and physiological characteristics to adapt to this environment which has become one of its areas of reproduction and dispersal This work aims at evaluating the morphometric variation of locusts in two different habitats located in the southern Sahara, natural and cultivated environments. The results of biometric analysis on male and female populations, conducted from 1993 to 2004, primarily on the elytra (E), femur (F) and head capsule (C), revealed the existence of differences between locusts from two locations. Population densities were low and did not exceed 500 individuals per hectare, except in April 2004 when a maximum of 10 000 individuals/ha was reached in Adrar. Morphometric ratios (E/F and F/C) of the studied pop...