DEVELOPMENT AND REPRODUCTIVE POTENTIAL OF THE CEREAL APHID SITOBION-AVENAE ON RESISTANT WHEAT LINES (TRITICUM-MONOCOCCUM)

The effect of wheat resistance in lines of Triticum monococcum L., on the reproductive performances of the cereal aphid (Sitobion avenae F.) was investigated. Aphids were reared from birth to adult moult either on resistant or susceptible wheat lines, and transferred as apterae t o both host genotypes. The influence of these transfers on the subsequ ent adult weight, gonad status and reproductive performances was evalu ated. Aphids transferred from resistant to susceptible plants proved a ble to compensate for their poor nymphal growth, mainly through additi onal embryo growth and an increase in the number of matured embryos wi thin the first 10 days of their adult life. Most aphids transferred fr om susceptible to resistant plants died within the first week followin g the transfer. Their most advanced embryos matured and were born, but subsequent embryo growth was quickly reduced. The reproductive strate gies adopted by S. avenae when facing plant resistance, and the hypoth esis of a resistant mechanism based on a poor nutritional state of the resistant plants are discussed.