Generation-dependent functional and numerical responses of Neoseiulus cucumeris (Acari: Phytoseiidae) long-term reared on almond pollen

Abstract

ABSTRACT It is important to know how the quality of predators changes during different generations of rearing. Neoseiulus cucumeris (Oudemans) reared on almond pollen for 30 generations (G1-G30) was evaluated for searching efficacy and ovipoisition behaviour on Tetranychus urticae Koch as prey. The functional and numerical responses were determined every ten generations by offering a range of prey densities (2, 4, 8, 16, 32, 64, and 128 nymphs) under standard conditions (25 ± 1°C, 60 ± 5% RH, and a photoperiod of L16:D8 h). In all generation tested N. cucumeris exhibited a type II functional response. The attack rate and handling time declined until G20, but increased from then onwards. The highest estimated maximum predation rate (T/Th ) was in G20 (86 prey/day), while the lowest was in G1 (53 prey/day). The quality of mass-reared predators did not decline against T. urticae prey after different periods of rearing on pollen. Mites reared for an extended period on almond pollen were equivalent or even better than mites reared for a short period because of higher predation and oviposition rates at each prey density. Based on this study and those we have already conducted, we propose almond pollen is a good candidate for the mass rearing of N. cucumeris for use in augmentative biological control programmes.