The Changing Rodent Pest Fauna in Egypt

The most serious known rodent pests in agricultural irrigated land are: Rattus rattus, Arvicanthis niloticus and Acomys sp. Occasionally there are rodent outbreaks in agricultural plantations. The changing agro-ecosystem in the present and future agricultural plantations is expected to affect the status of the following potential rodent pest species: Spalax ehrenbergi aegyptiacus, Nesokia indica, Jaculus orientalis, and Gerbillus gerbillus gerbillus. Basic studies are needed to quantify damage including water loss, which is caused by rodents, forecast of rodent outbreaks, and integrated control of rodents in agricultural projects. INTRODUCTION The depredations of rodents and the struggle to prevent them will never diminish, even though man desires to raise his standard of living and health. In the face of the rapidly rising human population in Egypt, the problem has become more acute. The pattern of rodent populations is changed when man converts deserts, forests and rangeland into food or fiber production schemes. This is a common feature of the Middle East region, including Egypt. In some cases such activities are carried out without prior knowledge of the actual fauna of the area, and the natural predators of rodents are driven away, or killed for food, or for the sake of their skins. As a result rodents increase in number and different rodent species may appear. The causes of shifts in species distribution are mostly due to changes in environmental conditions and the superior survival strategy of the replacing species. There are several examples of a predominant rodent species being replaced by another one under various ecological conditions. There is the replacement of Rattus rattus by Bandicota bengalensis in Calcutta (Seal and Banerjee, 1966), Rattus rattus and Mus musculus by Tatera i. indica in Rajasthan (Jain, 1970), and the replacement of Meriones hurrianae and T. i. indica by Gerbillus gleadoni after a control campaign in Rajasthan desert (Prakash, 1975). The present note discusses the changing agro-ecosystem in Egypt and its possible impact on the status of rodent pest problems concerning the prevailing species and their densities. IMPORTANT RODENT PEST SPECIES IN EGYPT The most important known rodents as agricultural pests and vectors in Egypt are grouped as follows (Hoogstral, 1963): Commensal Rodents These include rodents of the Ethiopian fauna (Arvicanthis niloticus and Acomys) and other rodents (Rattus norvegicus, Rattus rattus, and Mus Musculus) which are the Near East Africa components.