title: Influence of diet on life table parameters of Iphiseius degenerans (Acari: Phytoseiidae).
abstract: Abstract. Studies on the reproduction, longevity and life table parameters of Iphiseius degenerans (Berlese) were carried out under laboratory conditions of 25 +/- 1 degree C, 75 +/- 5% RH and 16L:8D h. As food sources for the predatory mite, Ricinus communis L. pollen, all stages of the spider mite Tetrranchus urticae Koch, Frankliniella occidentalis (Pergande) larvae, and Ephestia kuehniella Zeller eggs were selected. All diets were accepted as food by the adult mites. Female longevity ranged from 29.5 to 42.4 days, the highest value was recorded on a diet of Ephestia eggs. The highest percentage of females escaping the experimental arena was observed on the diet consisting of thrips larvae. The highest oviposition rate (1.9 eggs/female.day) was recorded when the predator was fed on spider mites on an artificial substrate. For other diets, oviposition rates ranged from 1.0 to 1.3 eggs/female.day. The intrinsic rate of natural increase (r(m)) of I. degenerans varied between 0.015 and 0.142 females/female x day. The diet consisting of castor bean pollen resulted in the highest population growth whereas the diet on spider mites brushed off onto a bean leaf arena resulted in the slowest population growth. This can be explained by the inability of the predator to cope with the webbing of T. urticae, and the high escape rate of the progeny when reared on spider mites. The percentage of females in the offspring ranged from 40 to 73%.
authors.affiliation: Laboratory of Agrozoology, Department of Crop Protection, Faculty of Agricultural and Applied Biological Sciences, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium. Isabelle.Vantornhout@UGent.be
authors.forename: Isabelle
authors.initials: I
authors.lastname: Vantornhout
authors.forename: Hilde Leen
authors.initials: HL
authors.lastname: Minnaert
authors.forename: Luc
authors.initials: L
authors.lastname: Tirry
authors.forename: Patrick
authors.initials: P
authors.lastname: De Clercq
mesh_terms: D000818:Animals; D005247:Feeding Behavior / Q000502:physiology; D005260:Female; D008018:Life Cycle Stages; D015993:Life Tables; D008136:Longevity / Q000502:physiology; D008297:Male; D008925:Mites / Q000502:physiology*; D010063:Ovum; D011058:Pollen; D012098:Reproduction / Q000502:physiology