Pakistan Journal of Biological Sciences1028-88801812-5735Asian Network for Scientific Information10.3923/pjbs.2006.2802.2807 Spodoptera littoralis (Boisd.)]]>AminTarek R.El-EninSalah AboEllakwaTakwa H.122006915Nine artificial diets were prepared by buffer solutions differing in their pH and molarities. They were fed by the fourth larval instar of Spodoptera littoralis for 4 days for testing the ability of alternation in physicochemical conditions of the diets to induce significant changes in nutritional indices, total carbohydrates and fitness of the larvae. pH had a significant reduction on weight gain, RCR (relative consumption rate) and total carbohydrates. On the other hand, the effect of different buffer molarities was significant on weight gain, RGR (Relative Growth Rate), RCR, ECI (efficiency of conversion of ingested food), ECD (efficiency of conversion of digested food) and total carbohydrates. The interaction between the both factors was high as observed in most parameters. AD (Approximate Digestibility) demonstrated that digestion was not adversely affected, which might indicates that midgut has a good buffering system. It was concluded that larvae probably to over come unsuitable physicochemical conditions of the introduced diets, increased their demand on energy through consuming digested or assimilated food like carbohydrates instead of building new tissues, which finally influencing larval performance parameters.]]>Amin, T.R. and N.A. El-Halafawy,2001284957Appel, H.M. and L.W. Maines,1995Lymantria dispar) caterpillars.]]>41241246Appel, H.M.,19941994pp: 209-223pp: 209-223Berenbaum, M.,1980115138146Crompton, M. and L.M. Birt,1967Lucilia cuprina.]]>1315751592Dow, J.A.T.,1984246633635Dow, J.A.T.,198719187328DuBois, M., K.A. Gilles, J.K. Hamilton, P.A. Rebers and F. Smith,195628350356Felton, G.W., K. Donato, R.M. Broadway and S.S. Duffey,1992Spodoptera exigua.]]>38277285Johnson, K.S. and G.W. Felton,199642191198Karowe, D.N. and M.M. Martin,1993Manduca sexta (Lepidoptera: Sphingidae).]]>394752Kurkdjian, A. and J. Guern,198940271303Lavy, D., M.J. Vanrijn, H.R. Zoomer and H.A. Verhoef,2001Oniscus asellus and Porcellio scaber.]]>261825Lechowicz, M.J.,19831983pp: 67-82pp: 67-82Lindroth, L.L., M.A. Barman and A.V. Weisbrod,1991Lymantria dispar. Effects on larval performance and detoxication enzyme activities.]]>374552Mattson, W.J. and J.M. Scriber,19871987pp: 105-146pp: 105-146Meisner, J., I. Ishaaya, K.R.S. Ascher and M. Zur,1978Spodoptera littoralis larvae.]]>7158Navon, A., J. Nesbitt, W. Henzel and H. Lipke,1985Manduca sexta and Spodopters littoralis.]]>5285291Schultz, J.C. and M.J. Lechowicz,1986Lymantria dispar).]]>71133137Shorey, H.H. and R.L. Hale,196558522524Soo-Hoo, C.F. and G. Frankel,1966Prodenia eridania (cramer).]]>12711730Waldbaeur, G.P.,19685464466