Kinds and Distribution of Wild Rodents and Their Ectoparasites in EgyptRice-field rats of Lower sind: abundance, reproduction and diet

A survey was made to determine the kinds and distribution of wild rodents and their ectoparasites and to provide preliminary data on relationship to temperature, humidity, soil and vegetation conditions in Egypt. The areas investigated were the cultivated Nile Valley, and the Eastern and Western Deserts. The kusu rat, Arvicanthis niloticus, was found chiefly in proximity to cultivated fields in the Nile Valley. Gerbillus gerbillus, G. pyramidum, Jaculus jaculus, and Meriones crassus were restricted to barren desert regions, Jaculus orientalis, Meriones shawi, and Psammomys obesus were located in the coastal area of the Western Desert. The bandicoot rat, Nesokia indica, was restricted to the low-lying saline areas in the Western Desert. A total of 178 rodents, including 9 species, was collected. The chief factors governing the distribution of these rodents were the type of soil, micro-topographic features, availability of suitable food plants, and micro-climatic conditions, especially humidity within the burrows. Humidity was always lower and temperature always higher outside of the burrows than those within the burrows. A total of 1149 ectoparasites representing 23 species was collected during July, August, September, and part of October, 1953. Of this number 365 fleas were recovered from 56 rodents; 146 ricks from 30 rodents; 252 mites, from 7 rodents; and 386 lice from 4 rodents. Nests examined for ectoparasites yielded 120 ticks; 40 fleas; 284 mites; and 12 lice. The nest afuna also included 559 free-living mites (oribatids and phytoseids) and miscellaneous arthropods representing 7 orders.Data on the abundance, reproduction and diet of rice field rats were collected during three rice seasons. At rice harvest, Bandicota bengalensis nearly doubled its litter size and tripled its pregancy rate and greatly increased in abundance. Millardia meltada remained abundant and maintained a relatively high pregnacy rate over all stages of crop development. These differences corresponded to differences in diet. Before the onset of grain ripening, the diet of Millardia contained more high-energy food (weed seeds, insects and scattered grain) while the diet of Millardia contained more high-energy food (weed seeds, insects and scattered grain) while the diet of Bandicota contained primarily low-energy food (rice stems and unidentified plant fibres); although both species ate principally rice at harvest. During most months, Nesokia indica was seldom caught above ground and ate mostly unidentified plant fibres. However, when grain ripened, Nesokia was caught on the surface and stomachs contained principally rice grain. Nesokia showed a lower pregnancy rate and smaller litter size, but apparently greater adult survival. They bred more often in the cooler months, during and after harvest. Some information on other topics is also presented, such as: sexual activity in males; substrate preference; relative adult longevity; the effect of excessive flooding of rice paddies; and the importance of underground rice caches, rice field weeds and swamp land to overwintering Bandicota. Estimates of the relative damage to the crop caused by each species at different stages of crop development were made by using data on rodent diet and abundanc