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.

A Pollen Diet Confers Ultraviolet-B Resistance in Phytoseiid Mites by Providing Antioxidants

“…This suggests that N. californicus eggs were commonly vulnerable to UVB radiation at their embryonic development periods, and our findings in this study show that maternal pollen diet mitigated UVB damage during the vulnerable periods of eggs. We also found efficient photoreactivation in N. californicus, line with Nakai et al (2018) (but see Koveos et al, 2017). Interestingly, maternal diet source also affected the photoreactivation efficiency of eggs.…”

“…Phytophagous spider mites and predacious phytoseiid mites suffer deleterious effects from solar ultraviolet-B (UVB, 280-315 nm wavelength) radiation (Ohtsuka and Osakabe, 2009;Onzo et al, 2010;Sakai and Osakabe, 2010;Sakai et al, 2012;Osakabe, 2012, 2014;Koveos et al, 2017). UVB radiation generates DNA lesions such as cyclobutane pyrimidine dimers (CPD) and (6-4) photoproducts (6-4PP; Wang et al, 1974;Sinha and Häder, 2002;Murata and Osakabe, 2017), as well as reactive oxygen species (ROS), such as singlet oxygen, which cause oxidative damage to DNA (Kielbassa et al, 1997;Zhang et al, 1997;Cadet et al, 2015) and lipid peroxidation (Girotti, 1998;Miyamoto et al, 2014;Morita et al, 2016;Atarashi et al, 2017).…”

“…Upper leaf surfaces may also be predator-free spaces, because predacious phytoseiid mites are more vulnerable to UVB radiation than spider mites (Onzo et al, 2010;Tachi and Osakabe, 2012;Koveos et al, 2017). Nakai et al (2018) reported that the egg hatchability and survival rate of hatched larvae of the phytoseiid mite Neoseiulus californicus (McGregor) after exposure to UVB radiation is higher when parent females feed on P. citri than when they feed on T. urticae.…”

“…Spider mites are potentially reactivated from UV damage through photoenzymatic repair of DNA lesions by CPD photolyase using energy from UVA (315-400 nm wavelength) and visible lights (photoreactivation; Osakabe, 2014, 2017;Suzuki et al, 2014) though no genes of (6-4) photolyase that repairs 6-4PP are found in T. urticae genome (Grbić et al, 2011). Nakai et al (2018) reported a marked photoreactivation in N. californicus (but see Koveos et al, 2017). The enzymes associated with photoreactivation might be protected from oxidative stresses by non-enzymatic antioxidants.…”

Cross-talk between high light stress and plant defence to the two-spotted spider mite in Arabidopsis thaliana

“…For instance, UVA and UVB radiation have an effect on mite survival, reproduction, and spatial distribution on host-plants (Ohtsuka and Osakabe 2009;Sakai and Osakabe 2010). It was also determined that visible light treatment after UVB treatment caused photoreactivation of adult females, resulting in the increased survival recovery of T. urticae and Tyrophagus putrescentiae (Santos 2005), and effects on the egg hatchability of T. urticae as well as predatory mite (Koveos et al 2017;Murata and Osakabe 2014). Here, we described the first evidence of a regulatory role for HL in the plant response to mite herbivory.…”