Life table and biological studies of Harmonia axyridis Pallas (Col., Coccinellidae) reared on the grain moth eggs of Sitotroga cerealella Olivier (Lep., Gelechiidae)

The developmental period of immature stages, survival per cent, longevity, fecundity and life table parameters of Harmonia axyridis by feeding on fres h and frozen grain moth eggs (GME) of Sitotroga cerealella were studied und er laboratory conditions. The effect of crowding adults on fecundity of fem ales was also determined. The total developmental time from egg hatching to adult eclosion ranged from 18.89 +/- 0.32 to 22.5 +/- 0.21 days on fresh a nd frozen GME, respectively. Survival per cent from egg hatching to adult e mergence differed significantly when the predator fed on the two diets of G ME. Also, pupal and adult weights were affected by feeding on fresh and fro zen GME. There were no significant differences in longevity of females, whi le there were significant variations in fecundity of females and longevity of males. The calculated values of T, DT, R-o, r(m), and e(rm) were high by feeding on fresh GME. Morever, rates of survivorship (Lx), and maximum ovi position per female per day (Mx) were higher when the predator was reared o n fresh than on frozen GME. Crowding conditions of predator adults affected the fecundity of females due to egg cannibalism by both males and females of the predator.