Improved UV-resistance by pollen feeding in phytoseiid mite
Abstract: Pollen, which many phytoseiid mite species feed on, is frequently exposed to solar radiation which includes deleterious ultraviolet-B (UVB) fractions, so that pollen should comprise protective materials to protect a germ cell from ultraviolet radiation. Phytoseiid mites are vulnerable to (UVB) radiation. If phytoseiid mites can obtain the protective materials from pollen, significance of pollen-feeding is not restricted to the nutrition but also important for adaptation to solar UVB radiation. Survival rates after UVB irradiation were higher in adult Neoseiulus californicus females fed on tea pollen than that fed on Tetranychus urticae. N. californicus females fed on tea pollen produced more eggs than that fed on T. urticae after UVB irradiation. The protective effects were also observed in eggs laid by females fed on tea pollen. We also compared the protective effects of tea pollen, peach pollen and T. urticae on N. californicus. In both egg hatchability and survival of adult females after UVB irradiation, tea pollen showed largest protective effects, followed in order by peach pollen and T. urticae. Then, UVB absorbance and antioxidant activity of methanol extracts from tea pollen, peach pollen and T. urticae were analyzed. The UVB absorbance was largest in peach pollen, followed in order by tea pollen and T. urticae. Antioxidant activity was highest in tea pollen, followed in order by peach pollen and T. urticae. Finally, we identified antioxidant components in tea pollen and peach pollen. Our findings suggest that antioxidant activity (and UVB absorbance) by pollen components contributes to improve UVB resistance in N. californicus.