Nature and Science 2016;14(12) http://www.sciencepub.net/nature 71 Toxicological Effects of Lagocephalus scleratus fish extracts against Culex pipiens (Diptera: Culicidae) Ahmed I. Hasaballah, Ahmed N. Alabssawy, Ahmed Z.I. Shehata Department of Zoology, Faculty of Science, Al-Azhar University, Nasr City, Cairo, Egypt. Ahscience09@yahoo.com Abstract: Three extracts of Skin (SE), Muscle (ME) and Viscera (VE) of Lagocephalus scleratus were evaluated against immature and mature stages of Culex pipiens to assess the toxicity, LC 50 , fecundity, egg hatchability and some biochemical parameters. The survival potential of larval stage was highly affected by the treatment with the tested extracts. On the basis of LC 50 , ME was the most toxic one against the larval stage followed by SE and VE. The late toxicity of fish extracts tested on the adult females resulted from larvae treated with the LC 50 of each extract decreased the number of eggs laid by female. The fecundity recorded 88.3±2.9, 136.7±7.6 and 150±5 eggs/♀ for females resulted from larvae treated with the LC 50 of ME, SE and VE; respectively, compared to 171.7±7.6 eggs/♀ for control females. The hatchability percent of eggs laid by females treated with the LC 50 of ME, SE and VE was decreased to 33.9, 51.3 and 60%; respectively, compared to 90.3% for eggs laid by untreated females. A marked decrease in total carbohydrate, lipid and protein contents in the whole body of males and females, C. pipiens resulted from larvae treated with the LC 50 of ME, SE and VE were observed. It is clear from the results obtained in this study that puffer toxins are effective in the mosquito control. [Ahmed I. Hasaballah, Ahmed N. Alabassawy, Ahmed Z.I. Shehata. Toxicological Effects of Lagocephalus scleratus fish extracts against Culex pipiens(Diptera: Culicidae). Nat Sci 2016;14(12):71-77]. ISSN 1545-0740 (print); ISSN 2375-7167 (online). http://www.sciencepub.net/nature. 13. doi:10.7537/marsnsj141216.13. Key words: L. scleratus, C. pipiens, Toxicity, reproduction. 1. Introduction: Mosquitoes top all the insect-vectors in transmission of serious zoonotic diseases worldwide. Anopheles stephensi, Aedes aegypti and Culex pipiens are the vector mosquitoes of malaria, dengue and lymphatic filariasis, respectively. Over two billion people in tropical countries are at risk from mosquito borne diseases and the search for effective vaccines against these diseases is still in progress (WHO, 2008). In Egypt, C. pipiens is widely distributed (Mikhail et al., 2009), which has natural and artificial breeding, sites in the endemic and non-endemic villages (Harb et al., 1993). Apart from filariasis, Culicini, mainly C. pipiens transmit Sindbis virus (Wilson, 1991), West Nile Virus, Rift Valley Fever and Dog Heartworm (El-Bahnasawy et al., 2013). The unplanned use of chemical insecticides during the past few decades to control insect pests have resulted in serious consequences such as insect resistance, mammalian toxicity, bioaccumulation through food chains, environmental contamination and risk for human health (Klein, 1976). This necessitates the search for new sources for insect control agents. The marine environment represents a treasure of useful products a waiting discovery for the treatment of fungal, parasitic, bacterial and viral diseases and also as insecticidal products. A small number of marine plants, animals and microbes have already yielded more than 12000 novel chemicals, with hundreds of new compounds still being discovered every year (Donia and Hamann, 2003). Secondary metabolites of marine organisms differ from that of terrestrial organisms. Bioactive compounds isolated from marine organisms exhibits various biological activities such as anti-cancer, anti- inflammatory, antifungal, antimicrobial and mosquito larvicidal properties (Gul & Hamann, 2005; Venkateswara Rao et al., 1995, 2008). The extracts of marine sponges Clathria longitoxa, Callyspongia diffusa, Haliclona pigmentifera, Sigmadocia carnosa and Denrilla nigra showed significant insecticidal activity against mosquito larvae and agricultural pests (Baby et al., 2010). The larvicidal potential of prawn Nematopalaemon tenuipes and sea cucumber Holothuria scabra extracts have been reported (Narsinh et al., 2004). In the present paper we report the toxicological effects of different L. scleratus puffer fish extracts (PFEs) against C. pipiens. 2. Materials and Methods. 2-1- Origin and laboratory maintenance of the mosquito colony: Mosquitoes used in this study were Culex pipiens L., they were collected from Abu-Rawash, Giza governorate, then were reared for several generations, in the insectary of medical entomology at the department of zoology, faculty of science, under controlled conditions at temperature of 27±2 °C, relative humidity 70±10% and 12-12 light-dark