Functional response of Cheilomenes sexmaculata (Fab.) to increasing population densities of cotton aphid, Aphis gossypii (Glover) at different time intervals

Abstract

Laboratory investigations were conducted during the year 2017-2018 to determine the functional response of adult ladybird beetle Cheilomenes sexmaculata to increasing prey densities of Aphis gossypii on cotton at different time intervals of 12 hrs and 24 hrs after exposure. The results revealed a density dependent, Type II functional response of C. sexmaculata to A. gossypii at both the time periods. Prey consumption increased curvilinearly with an increase in prey density. Type II functional response was determined by a logistic regression model. The parameters estimated from the random predator equation (The attack rate ‘a’ and handling time ‘Th’) suggest that the predator was more efficient as a biocontrol agent during the first 12 hrs. of exposure to the prey than after that time period.