ABSTRACT
An investigation was carried out to evaluate the influence of symbiotic bacteria associated with Culex pipiens L. on preoviposition and blood meal digestion periods, and reproductive potential [fecundity and fertility]. Aposymbiotic females were obtained by feeding the normal females on 10% sucrose solution mixed with antibiotic [Tarivid] for three days before feeding them on normal blood meals from a pigeon host. A total of 4 genera were previously isolated from the midgut of C. pipiens. These genera were; Bacillus, Streptococcus, Staphylococcus and Salmonella and Shigella. It seems that the period of blood meal digestion preceded the pre-oviposition period of both bacterial free females and bacterial free females treated with one of the aforementioned bacteria. In addition, it is obviously clear that, the presence of the two bacterial genera; Bacillus and Staphylococcus in the midgut of C. pipiens is essential for normal and high fecundity. Generally, it is evident that the symbionts [gut bacteria] are essential for the completion of embryonic development