The performance of Macrosiphoniella millefolii and Myzus persicae on Achillea collina

This paper compares the development of the polyphagous aphid Myzus persicae Sulzer, considered as a generalist, and the oligophagous aphid Macrosiphoniella millefolii (De Geer), considered as a specialist, on yarrow (Achillea collina Becker ex Reichenbach). Yarrow is a medicinal plant rich in bioactive secondary metabolites that have possible effects on the development of phytophages, including aphids. Age specific life tables for cohorts developing under different constant temperatures were constructed and analyzed using standard techniques, and complemented with Jackknife estimates of the intrinsic rate of increase and its standard error. The parthenogenetic wingless morphs of the two species differed in the immature developmental time and survival, and in adult fecundity and life span. At high temperatures, the intrinsic rate of increase as the overall metric of performance tended to be higher for the generalist than for the specialist aphid species, while the opposite appears to occur at low and medium temperatures. Further insight into the complex interactions between yarrow and aphids requires that their genetic diversity is taken into account. The study of yarrow-aphid-natural enemy population interactions requires additional information on biomass dynamics, aphid morph differentiation and the performance of biological control agents.