The Effects of Alternative Foods on Life History and Cannibalism of Amblyseius herbicolus (Acari: Phytoseiidae)

SIMPLE SUMMARY: Suitable foods are essential for the successful mass rearing of natural enemies and can directly affect their quality and performance, which are the determinants of the success of biological control programs. Most predatory mites of the family Phytoseiidae are omnivorous, meaning they can obtain nutrients from both prey and plant sources. However, different kinds or species of alternative foods have significantly different effects on the development, survivorship and reproduction of predatory mites. Meanwhile, food quality also significantly affects the cannibalistic behavior of predatory mites, which limits the application of alternative foods in the mass rearing of the predators. Amblyseius herbicolus (Chant), an excellent predator of various phytophagous mites and insects, has recently gained attention as a crucial biocontrol agent. We evaluated the effects of A. herbicolus feeding on six alternative foods (Oulenziella bakeri, Tyrophagus putrescentiae, Aleuroglyphus ovatus, almond pollen (Prunus armeniaca), apple pollen (Malus pumila), maize pollen (Zea mays)), and natural prey (Tetranychus urticae) on its life history and cannibalism. Our findings indicated that O. bakeri and almond pollen performed best for A. herbicolus as potential foods for mass rearing and for supporting its population after release in the fields. ABSTRACT: The development, survivorship, fecundity, and cannibalism of the predatory phytoseiid mite, Amblyseius herbicolus (Chant), fed six different alternative foods (Oulenziella bakeri, Tyrophagus putrescentiae, Aleuroglyphus ovatus, almond pollen (Prunus armeniaca), apple pollen (Malus pumila), maize pollen (Zea mays)), and natural prey (Tetranychus urticae) were determined in the laboratory. Our findings indicated that A. herbicolus that fed on all six alternative foods could normally complete its developmental and reproductive cycles. The shortest pre-adult developmental duration was observed when A. herbicolus fed on almond pollen (4.91 d) as well as T. urticae (4.90 d), and the longest when it fed on maize pollen (6.24 d). Pre-adult survival rates were higher when the predator fed on almond pollen (0.99), maize pollen (0.96), and O. bakeri (0.93). The highest fecundity was observed when A. herbicolus fed on apple pollen (28.55 eggs/female), almond pollen (26.06 eggs/female), and O. bakeri (26.02 eggs/female) in addition to T. urticae (48.95 eggs/female), and the lowest when it fed on maize pollen (7.84 eggs/female). The highest value of the intrinsic rate of increase (r) was obtained when A. herbicolus fed on O. bakeri (0.202 d(−1)) in addition to T. urticae (0.210 d(−1)), followed by almond pollen (0.163 d(−1)), and the lowest was when it fed on maize pollen (0.064 d(−1)). Cannibalism of conspecific eggs by adults of A. herbicolus did not occur when O. bakeri and T. urticae were provided. The cannibalism rate of the predatory mite was the lowest when fed on almond pollen, T. putrescentiae, and A. ovatus and the highest on apple pollen. Above all, when fed on O. bakeri and almond pollen, and with no or low cannibalism rate, A. herbicolus had the best development, survivorship, fecundity, and population parameters. Therefore, O. bakeri and almond pollen could be potential alternative foods for mass rearing programs of A. herbicolus or to support its population in the fields.