Effect of Parental Age at Coition on Reproduction of Lysiphlebia mirzai (Hymenoptera: Braconidae)
Pandey, Sharmila; Singh, Rajendra
Third instar nymphs [L3] of the aphid species Rhopalosiphum maidis (Fitch 1856) were exposed individually each to a female [F] of the parasitoid wasp species Lysiphlebia mirzai Shuja-Uddin 1975. These were of variable age-groups (0-12 h, 48-60 h, 96-108 h old) reciprocally inseminated by males [MM] of variable age-groups (0-12 h, 48-60 h, 96-108 h old). The results indicated: (a) With the increase of parental age, the total progeny yield by the F (6-day observation period) decreases considerably from 154.6±21.1 SD progeny (0-12 h old) to 57.2±7.5 SD progeny (96-108 h old), and the variation in the maternal age causes greater variance in the data than the paternal age; (b) the progeny sex ratio [SR] (measured as proportion of MM in the population) is minimum (SR = 0.36±0.05 SD), when parents mate just after emergence (0-12 h old), but increases about 50% (SR = 0.53±0.05 SD), when the parents are inseminated after 96-108 h of emergence and the FF are allowed to oviposit. The analysis of variance shows that the maternal age influences the total progeny yield; also the SR and the generalised reproductive index is much greater than the paternal age. The implications of these results are discussed with reference to the maximisation of yield of total progeny and particularly with respect to FF for mass propagation and field release in biological control.