Impact of the secondary plant metabolite Cucurbitacin B on the demographical traits of the melon aphid, Aphis gossypii

Cucurbitacin B is a natural triterpene present in plants of Cucurbitaceae family, which are among the host plants for melon aphid, Aphis gossypii . In present study we characterized the effects of two cucurbitacin B concentrations on the biological parameters of adults (F 0 ) and of juveniles and adults of their progeny (F 1 ). The results showed that cucurbitacin B at 25 ppm significantly reduced the adult longevity and fecundity of both F 0 and F 1 generation. Exposure of F 0 generation to 25 ppm though reduced the demographic traits of F 1 including the intrinsic rate of increase r (day −1 ), generation time T (day), finite rate of increase λ (day −1 ), however, only net reproductive rate R 0 (offspring/individual) decreased significantly. While 100 ppm reduced not only the longevity and fecundity of F 0 generation but also the longevity of F 1 generation. Fecundity of F 1 was not affected by 100 ppm of cucurbitacin B, however, R 0 (offspring/individual) and T (day) of F 1 generation were lower than the control population. These results support the hypothesis that high contents of cucurbitacin B caused negative impact on melon aphid and could be used as a lead for classical selection of resistant varieties of plants that are main hosts for the melon aphid.