Abstract
Apterous parthenogenetic females of the Pea Aphid collected in the Tokachi district of Hokkaido Island (Tokachi strain), were reared on chemically-defined artificial diets with different sucrose concentration and pH (25-55g/100ml, pH 6-10), after two days of reproduction on broad-bean seedlings, Vicia faba L., at 15±1°C, under 16L:8D. Survival rate, longevity and the number of offspring per aphid were maximum when reared on a diet of 45g/100ml sucrose concentration and pH 8.3. The survival rate (75%) at the 10th day of rearing and the mean longevity (17.8±2.0 days) of the aphids on the best artificial diet were not significantly different from the values for aphids reared on broad bean (85.7% and 20.5±1.7 days, respectively). The mean number of offspring (32.0±2.4) per diet-reared aphid was 45.3% of the value for aphids reared on broad bean. In our experiments, the best combination of sucrose concentration and pH for the artificial diet for the Pea Aphid (Tokachi strain) is different from the results of Akey and Beck (1972) for the same species (Wisconsin strain). This indicates that there are variations in optimum sucrose concentration and pH for artificial diet between aphid strains.
