Prey instar preference and functional responses of Mallada basalis (Walker) (Neuroptera: Chrysopidae) to different life stages of Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae)

Prey instar preference and functional responses of 2- and 3-instar Mallada basalis (Walker) (Neuroptera: Chrysopidae) larvae to 1- to 3-instar Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) nymphs and adults were assessed in laboratory. Results indicated that both 2- and 3-instar M. basalis larvae preferred young over old P. solenopsis nymphs and adults were the least preferred. The 3-instar M. basalis larvae preyed more adult P. solenopsis than 2-instar larvae. Mallada basalis exhibited type II functional responses to prey densities: An increase in prey density leads to an increase in consumed preys. Regardless of P. solenopsis stages, the number of preys consumed by the 3-instar M. basalis larvae was greater than that by the 2-instar larvae. Attack rates and handling times differed depending on prey and predator stage combinations. The highest attack rate (1.1874) and lowest handling time (0.0040 h) were observed for the 3-instar M. basalis larvae fed on the 1-instar P. solenopsis nymphs. Regardless of P. solenopsis stages, the attack rate of 3-instar M. basalis was greater than 2-instar, whereas the reverse held regarding handling time. The findings collectively indicated that 3-instar M. basalis larvae have greater potential than 2-instar as efficient biological control agent of P. solenopsis. In developing real world biological control programs, however, the 2-instar M. basalis may be released if necessary since the final efficacy of the predator is the summation of the 2- and 3-instar M. basalis.