Abstract
Fundatrices of Myzus persicae (SULZER) reared on radish showed a wider range in the number of ovarioles (10-18, x=14.7, n=50) than apterous virginoparae of the third generation (fundatrix: first generation; 10 except for an individual with 9, n=50). The total fecundity of fundatrices ranged from 61 to 185 progeny (x=112.8, n=6) at 20±1°C (15L-9D) and 23 to 138 progeny (x=72.1, n=29) under natural conditions. Of these fundatrices, 4 individuals produced a larger number of progeny (133, 134, 138, 185) than anticipated from the projected maximum fecundity of virginoparae (120). The maximum number of progeny produced by a fundatrix during 4 days ranged from 23 to 33 at 20±1°C. The rate of 33 progeny/4 days was higher than the maximum rate in virginoparae (28 progeny/4 days) so far recorded under the same conditions. Thus fundatrices are potentially more fecund and have a higher rate of larviposition than subsequent generation virginoparae, presumably as a result of the larger number of ovarioles.
