The spatial distribution of the two-spotted spider mite Tetranychus urticae Koch is biased toward the lower surfaces of leaves as compared with the upper leaf surfaces on their host plants. Because of the deleterious effects of solar ultraviolet (UV) irradiation, we hypothesized T. urticae remains on lower leaf surfaces as an adaptation to avoid solar UV radiation (UVR). We examined the effects of solar UVR components on females and tested whether spatial distribution was associated with solar UVR avoidance. Attenuation of solar UVR using UV opaque film increased fecundity and reduced the movement of females from the upper to the lower leaf surfaces. In contrast, diverting solar UVR to the lower leaf surface using a light reflection sheet caused the mites to move from the lower to the upper leaf surfaces; however, attenuated UV reflection did not, suggesting that they occupy the lower leaf surface to avoid solar UVR. In monochromatic UVR tests, no eggs hatched when placed under 280-300 nm radiation, whereas almost all eggs hatched at 320-360 nm. Adult females, however, did not avoid wavelengths of 280 and 300 nm, but avoided 320-340 nm. We conclude that T. urticae exploit UVA information to avoid ambient UVB radiation.

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A strategy to modulate the in‐plane structural arrangement in preferentially oriented crystalline metal–organic framework (MOF) nanosheets assembled by a two‐dimensional interfacial reaction between porphyrin units and metal ion linkers is reported. Starting with a tetratopic porphyrin MOF nanofilm, NAFS‐2, the framework size and shape are modified by employing specially designed building units, a trans‐ditopic and an expanded tetratopic porphyrin, and Cu2+ linkers. Reducing the number of binding parts affords a MOF nanosheet, NAFS‐31, with a distorted in‐plane structure. Extension of the peripheral substituents, while maintaining the tetratopic porphyrin geometry, results in marked unit cell size enlargement in an undistorted square grid in the MOF nanofilm, NAFS‐41. The exquisite geometric control that these structural modifications entail is valuable to allow switching of chemical/physical properties of the nanosheets and lead to realization of their use in nanotechnological applications.

Solar ultraviolet-B (UVB) radiation has deleterious effects on plant-dwelling mites. We assessed the biological effects of UVB radiation on the eggs of the twospotted spider mite, Tetranychus urticae Koch, under both near ambient (UV?) and UV-attenuated (UV-) conditions from spring to autumn and compared them to the effects of temperature and humidity. The ambient daily UVB irradiance increased from January to August and then decreased rapidly until December, whereas egg hatchability under UV? was lowest in April (10.7%) and increased almost linearly until October (74.9-92.3%). In contrast, hatchability under UV-was consistently high (96.2-99.8%) through all seasons. For UV?, the stepwise multiple linear regression analysis supported the negative correlation of hatchability with cumulative UVB irradiance during egg periods (cumulative dose), but did not support that with the mean daily UVB irradiance (dose rate), suggesting that UVB-induced mortality in T. urticae eggs is cumulative dose dependent rather than dose rate dependent. The high mortality in April may have reflected the slower development caused by the relatively lower temperature and higher UVB radiation, increasing the cumulative dose, while the low mortality in October may have reflected the faster development caused by the relatively higher temperature and lower UVB radiation, decreasing the cumulative dose.

Plant-dwelling mites are potentially exposed to solar ultraviolet-B (UVB) radiation that causes deleterious and often lethal effects, leading most mites to inhabit the lower (underside) leaf surfaces. However, in species of spider mite belonging to the Genus Panonychus, a substantial portion of individuals occur on upper leaf surfaces. We investigated whether the upper leaf surfaces of citrus trees are favorable for P. citri, and to what extent they are tolerant to UVB radiation. If eggs are not adequately protected from UVB damage, females may avoid ovipositing on the upper surfaces of sunny leaves. To test this, we conducted laboratory experiments using a UVB lamp, and semioutdoor manipulative experiments. As a result, P. citri eggs are tolerant to UVB. Field studies revealed that the ratio of eggs and adult females on upper leaf surfaces were larger for shaded than for sunny leaves. However, 64-89% of eggs hatched successfully even on sunny upper leaf surfaces. Nutritional evaluation revealed that whether on sunny or shaded leaves, in fecundity and juvenile development P. citri reaped the fitness benefits of upper leaf surfaces. Consequently, P. citri is tolerant to UVB damage, and inhabiting the upper surfaces of shaded leaves is advantageous to this mite.