Abstract
The predatory mites, Neoseiulus cucumeris (Oud.) and Neoseiulus barkeri (Hughes) (Acari: Phytoseiidae), were collected from leaves of the kidney bean (Phaseolus vulgaris L.) growing at Hail District, Saudi Arabia, in 2017. Different biological aspects and life table parameters of both predators were evaluated by feeding on three insect egg species, Anagasta (Ephestia) kuehniella (Keller) (Pyralidae), Sitotroga cerealella (Oliv.) (Gelechiidae), and Spodoptera littoralis (Boisduval) (Noctuidae), as alternative food sources at 27 degrees C and 70% RH. Predators' developmental times were affected by food type. Duration of life cycle was significantly longer when N. cucumeris was provided with S. cerealella eggs (16.56 days for male and 15.42 days for female) than the other two kinds of insect eggs. Maximum time of life cycle of N. barkeri occurred for male fed on eggs of S. cerealela (18.82 days), likewise the minimum time was observed for male fed on eggs of A. kuehniella (9.92 days).The fecundity of both phytoseiid mites was the highest (25.06 eggs/female, with a daily rate of 2.05 eggs/female/day, for N. cucumeris and 23.26 eggs/female, with a daily rate of 2.04 eggs/female/day, for N. barkeri, respectively) by feeding on eggs of A. kuehniella. Fecundity was the lowest (13.37 eggs/female, with a daily rate of 1.48 eggs /female/ day and 10.35 eggs/female, with a daily rate of 0.84 eggs/female/day for the two predatory mites, respectively) on S. cerealella eggs. Food source affected all the life table parameters of both tested predatory mites. It was concluded that two phytoseiid mite species can be maintained successfully on the alternative food, A. kuehniella eggs, in lab trials whenever the natural prey types are scarce.