Effect of oleanolic acid on the growth and reproduction of the pea aphid

Oleanolic acid, a triterpenoid, has antifeedant, lethal, and avoidance effects on herbivorous insects. This study aimed to clarify the effects of oleanolic acid on the physiology of two color morphs of pea aphid (Acyrthosiphon pisum). For this, the pure artificial diet film feeding technology was applied and 5 groups of artificial diet, with different concentrations of oleanolic acid, were prepared to rear the green and red morph pea aphids in incubators. The following parameters were measured: survival rate, growth rate of relative daily average weight, ratio of winged phenotype, and percentage of reproducing individuals. The results showed that oleanolic acid had inhibitory effects on the growth and reproduction of the green morph, but did not affect the red morph. In the range of 0.1～2.0 mg·mL^–1, all the measured parameters (except the ratio of winged phenotype) of the green morph decreased with the increase of the oleanolic acid concentration, and the lowest data was obtained at 2.0 mg·mL^–1. The ratio of winged phenotype gradually increased with the increase of the oleanolic acid concentration and reached a maximum at the concentration of 1.0 mg·mL^–1, but then gradually decreased. These results will lay a technological and theoretical foundation for further studies on the physiological and behavioral mechanisms of how oleanolic acid affects the development and reproduction of the pea aphid.