The Gemini Planet Imager is a dedicated facility for directly imaging and spectroscopically characterizing extrasolar planets. It combines a very high-order adaptive optics system, a diffractionsuppressing coronagraph, and an integral field spectrograph with low spectral resolution but high spatial resolution. Every aspect of the Gemini Planet Imager has been tuned for maximum sensitivity to faint planets near bright stars. During first-light observations, we achieved an estimated H band Strehl ratio of 0.89 and a 5-σ contrast of 10 6 at 0.75 arcseconds and 10 5 at 0.35 arcseconds. Observations of Beta Pictoris clearly detect the planet, Beta Pictoris b, in a single 60-s exposure with minimal postprocessing. Beta Pictoris b is observed at a separation of 434 ± 6 milliarcseconds (mas) and position angle 211.8 ± 0.5°. Fitting the Keplerian orbit of Beta Pic b using the new position together with previous astrometry gives a factor of 3 improvement in most parameters over previous solutions. The planet orbits at a semimajor axis of 9:0 +0:8 −0:4 AU near the 3:2 resonance with the previously known 6-AU asteroidal belt and is aligned with the inner warped disk. The observations give a 4% probability of a transit of the planet in late 2017.high-contrast imaging | extreme adaptive optics | debris disks D irect imaging is a powerful complement to indirect exoplanet detection techniques. In direct imaging, the planet is spatially resolved from its star, allowing it to be independently studied. This capability opens up new regions of parameter space, including sensitivity to planets at >5 AU. It also allows spectroscopic analysis of the light emitted or reflected by the planet to determine its composition (1, 2) and astrometry to determine the full Keplerian orbital elements (3, 4).Imaging planets is extremely challenging-Jupiter is 10 9 times fainter than our sun in reflected visible light. Younger extrasolar planets are more favorable targets. During their formation, planets are heated by the release of gravitational potential energy. Depending on the exact formation process and initial conditions, a 4-Jupiter mass ðM J Þ planet at an age of 10 million years could have a luminosity between 10 −6 and 2 × 10 −5 L ⊙ (5), but this is still a formidable contrast ratio. To overcome this, astronomers combined large telescopes (to reduce the impact of diffraction), adaptive optics (to correct for phase errors induced by atmospheric turbulence), and sophisticated image processing (6, 7). This recipe in various combinations had achieved several notable successes (8-12). However, the rate of these discoveries remains low (13-15) in part because the number of suitable young stars in the solar neighborhood is low, and for all but the closest stars, such detection is limited to >20 AU, where planets may be relatively rare. To move beyond this limited sample, dedicated instruments are needed that are designed specifically for high-contrast imaging. One such instrument is the Gemini Planet Imager (GPI). GPI is a fully optimized high-con...

These authors contributed equally to this work Summary• Certain plant species hyperaccumulate selenium (Se) up to 0.6% of their dry weight. It is not known whether Se hyperaccumulation offers the plants any advantage. In this study the hypothesis was tested that Se can protect plants from invertebrate herbivory or fungal infection.• Indian mustard ( Brassica juncea ) plants grown with or without Se were subjected to herbivory by caterpillars ( Pieris rapae ) and snails ( Mesodon ferrissi ), or to fungal infection by a root /stem pathogen ( Fusarium sp.) and a leaf pathogen ( Alternaria brassicicola ).• When given a choice between leaves with or without Se (0.1% Se of leaf d. wt), the caterpillars strongly preferred leaves without Se ( P < 0.01), while the snails preferred leaves containing Se ( P < 0.015). When consumed, the Se leaves were lethal to the caterpillars. The snails showed no toxicity symptoms, even though their tissue Se concentrations were comparable with the caterpillars. Se-containing plants were less susceptible to infection by both fungi.• In conclusion, Se was shown to protect Indian mustard plants from fungal infection and from herbivory by caterpillars, but not by snails.

Acarodomatia are small tufts of hair or invaginations in the leaf surface and are frequently inhabited by several taxa of non-plant-feeding mites. For many years, ecologists have hypothesized that these structures represent a mutualistic association between mites and plants where the mites benefit the plant by reducing densities of phytophagous arthropods and epiphytic microorganisms, and domatia benefit the mite by providing protection from stressful environmental conditions, other predaceous arthropods, or both. We tested these hypothesized benefits of domatia to domatia-inhabiting mites in laboratory and growth chamber experiments. In separate experiments we examined whether domatia on the wild grape, Vitis riparia, provided protection against drying humidity conditions or predaceous arthropods to two species of beneficial mite: the mycophagous species Orthotydeus lambi, and the predaceous species Amblyseius andersoni. For both taxa of beneficial mite, domatia significantly increased mite survivorship in the presence of the predatory bug, Orius insidiosus and the coccinellids Coccinella septempunctata and Harmonia varigata. There was no evidence for a protective effect of domatia with a third species of predatory arthropod, lacewing larvae Chrysoperla rufilabris. In contrast, there was no evidence for either species of beneficial mite that domatia provided any protection against low humidity. Thus in this system the primary mechanism by which domatia benefit beneficial mites is by protecting these organisms from other predatory arthropods on the leaf surface.

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