title: Egg hatching response to a range of ultraviolet-B (UV-B) radiation doses for four predatory mites and the herbivorous spider mite Tetranychus urticae.
abstract: Egg hatchability of four predatory mites-Phytoseiulus persimilis Athias-Henriot, Iphiseius [Amblyseius] degenerans Berlese, Amblyseius swirskii Athias-Henriot, and Euseius finlandicus Oudemans (Acari: Phytoseiidae)-and the spider mite Tetranychus urticae Koch (Acari: Tetranychidae) was determined under various UV-B doses either in constant darkness (DD) or with simultaneous irradiation using white light. Under UV-B irradiation and DD or simultaneous irradiation with white light, the predator's eggs hatched in significantly lower percentages than in the control non-exposed eggs, which indicates deleterious effects of UV-B on embryonic development. In addition, higher hatchability percentages were observed under UV-B irradiation and DD in eggs of the predatory mites than in eggs of T. urticae. This might be caused by a higher involvement of an antioxidant system, shield effects by pigments or a mere shorter duration of embryonic development in predatory mites than in T. urticae, thus avoiding accumulative effects of UV-B. Although no eggs of T. urticae hatched under UV-B irradiation and DD, variable hatchability percentages were observed under simultaneous irradiation with white light, which suggests the involvement of a photoreactivation system that reduces UV-B damages. Under the same doses with simultaneous irradiation with white light, eggs of T. urticae displayed higher photoreactivation and were more tolerant to UV-B than eggs of the predatory mites. Among predators variation regarding the tolerance to UV-B effects was observed, with eggs of P. persimilis and I. degenerans being more tolerant to UV-B radiation than eggs of A. swirskii and E. finlandicus.
authors.affiliation: Laboratory of Applied Zoology and Parasitology, School of Agriculture, Faculty of Agriculture, Forestry and Natural Environment, Aristotle University of Thessaloniki, 541 24, Thessaloniki, Greece. koveos@agro.auth.gr.
authors.forename: Dimitrios S
authors.initials: DS
authors.lastname: Koveos
authors.affiliation: Laboratory of Molecular Environmental Biology, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Laboratory of Applied Zoology and Parasitology, School of Agriculture, Faculty of Agriculture, Forestry and Natural Environment, Aristotle University of Thessaloniki, 541 24, Thessaloniki, Greece.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Terzidou
authors.affiliation: Laboratory of Applied Zoology and Parasitology, School of Agriculture, Faculty of Agriculture, Forestry and Natural Environment, Aristotle University of Thessaloniki, 541 24, Thessaloniki, Greece.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Kokkari
authors.affiliation: Laboratory of Applied Zoology and Parasitology, School of Agriculture, Faculty of Agriculture, Forestry and Natural Environment, Aristotle University of Thessaloniki, 541 24, Thessaloniki, Greece.
authors.forename: George
authors.initials: G
authors.lastname: Floros
authors.affiliation: Laboratory of Applied Zoology and Parasitology, School of Agriculture, Faculty of Agriculture, Forestry and Natural Environment, Aristotle University of Thessaloniki, 541 24, Thessaloniki, Greece.
authors.forename: Petros
authors.initials: P
authors.lastname: Damos
authors.affiliation: Laboratory of Applied Zoology and Parasitology, School of Agriculture, Faculty of Agriculture, Forestry and Natural Environment, Aristotle University of Thessaloniki, 541 24, Thessaloniki, Greece.
authors.forename: Nikos A
authors.initials: NA
authors.lastname: Kouloussis
mesh_terms: D000818:Animals; D005260:Female; D060434:Herbivory; D008925:Mites / Q000502:physiology / Q000528:radiation effects*; D010063:Ovum / Q000502:physiology / Q000528:radiation effects; D011235:Predatory Behavior; D011836:Radiation Tolerance; D040102:Tetranychidae / Q000502:physiology / Q000528:radiation effects; D014466:Ultraviolet Rays
keywords: Antioxidant system; Biological control; Photoreactivation; Phytoseiidae; Spider mites; UV-B irradiation