Suitability of Aphis gossypii Glover, Aphis fabae Scop. and Ephestia kuehniella Zeller eggs for the biology and life-table parameters of Adalia decempunctata (L.) (Coleoptera: Coccinellidae)

Abstract

Adalia decempunctata (L.) is a common predator in agroecosystems and the natural environment. Its biology and life table were studied in nymph/adult hosts of Aphis gossypii Glover, Aphis fabae Scop. and on the eggs of Ephestia kuehniella Zeller. Raw data of all individuals of A. decempunctata were analyzed using the age-stage, two-sex, life-table theory. The results of this study indicate a shortest immature developmental period (IDP) of A. decempunctata feeding on eggs of E. kuehniella (18.33 days) and the longest on A. fabae (21.82 days). The longest longevity was, however, after feeding on A. gossypii. The fecundity rate of females on E. kuehniella was the highest (2405.12 eggs/female). The intrinsic rates of increase of A. decempunctata were 0.177, 0.171 and 0.155 day-1 when feeding on A. gossypii, E. kuehniella eggs and A. fabae, respectively. The highest finite rates of increase (?) were 1.193 and 1.187 day-1 when reared on A. gossypii and E. kuehniella, respectively. The mean generation time for A. fabae (41.40 days) was significantly higher compared to other hosts. The results of this study showed that the quality of the host influenced to a great extent the rate of energy reserves in emerged females. We conclude that all three host species can be considered as essential preys. These hosts influence the larval developmental period and reproduction in adult A. decempunctata; however, the results of the biochemical assays pointed to A. gossypii and E. kuehniella eggs as preferred hosts.