Functional responses of immature stages of Propylea quatuordecimpunctata (Coleoptera: Coccinellidae) to Aphis fabae (Hemiptera: Aphididae)

Functional responses of immature stages of Propylea quatuordecimpunctata (L.) to varying densities of Aphis fabae Scopoli reared on Vicia faba L. were evaluated under laboratory conditions. All larval stages of the predator were starved for 12 h prior to being placed individually for 24 h in plastic containers with different densities of its prey, A. fabae, on potted V. faba plants. Logistic regression analysis of the proportion of aphids consumed as a function of initial density indicated that all larval instars of P. quatuordecimpunctata exhibited a type II functional response when searching for A. fabae on V. faba plants. Attack rates (0.059, 0.057, 0.065 and 0.064) and handling times (6.18, 2.37, 1.06 and 0.44) for first to fourth instar larvae, respectively, were estimated using Holling's disc equation.