A Comparison of Life History Parameters of Hippodamia variegata Feeding on either Aphis gossypii Glover or Acyrthosiphon pisum

Ladybird beetles are of a special standing in aphid biological control. They attack different aphid species and play an important role in suppressing aphid populations. One of the most conspicuous Coccinellids namely Hippodamia variegata, occurs in such different crops as alfalfa and vegetables. Life history parameters of this predator at 25 ± 1 ºC and 16:8 (L: D) photoperiodicity were evaluated. Different life stages of cotton as well as pea aphids were used as prey ad libitium. The results showed that intrinsic rates of increase (rm) when feeding on A. pisum and A. gossypii were 0.14 and 0.03 / day respectively. Finite rate of increase (λ) was 1.15 and 1.03, net reproductive rates (R0) were 118. 49 and 3.0, mean generation Times (T) amounted to 33.33 and 33.62, and Doubling Time (DT) 4.8 and 15.79 respectively when fed on A. pisum vs A. gossypii. The intrinsic birth rate (b) was 0.33 irrespective of prey types and death rate (d) amounting to 0.187 and 0.297. Comparing life history parameters showed that A. pisum is a more suitable prey for this predator which and could suitably be useful for mass rearing in the laboratory.