Seasonal-variation in reproductive potential: a programmed feature of aphid life-cycles
Individuals of six species of aphid from two families were dissected and the number of ovarioles recorded. Variation in ovariole number occurred within and between generations. The spring generation(s) in each species had the highest number. Generations with many ovarioles were more fecund than those with few. In those generations showing variability an individual with a high number of ovarioles was potentially more fecund and reproduced at a greater rate than individuals with few ovarioles. The changes in reproductive potential are programmed and anticipate predictable seasonal changes in habitat quality.