SummaryWe conducted the most extensive meta-analysis of plant and animal responses to elevated CO 2 to date. We analysed > 5000 data points extracted from 270 papers published between 1979 and 2009. We examined the changes in 19 animal response variables to the main effect of elevated CO 2 . We found strong evidence for significant variation among arthropod orders and feeding guilds, including interactions in the direction of response. We also examined the main effects of elevated CO 2 on: six plant growth and allocation responses, seven primary metabolite responses, eight secondary metabolite responses, and four physical defence responses. We examined these response variable changes under two-way and three-way interactions between CO 2 and: soil nitrogen, ambient temperature, drought, light availability, photosynthetic pathway, reproductive system, plant growth rate, plant growth form, tissue type, and nitrogen fixation. In general we found smaller effect sizes for many response variables than have been previously reported. We also found that many of the oft-reported main effects of CO 2 obscure the presence of significant two-and three-way interactions, which may help better explain the relationships between the response variables and elevated CO 2 .
The spotted-wing drosophila (Drosophila suzukii Matsumura) is an invasive species of Asian origin that is now widely distributed in North America and Europe. Because of the female's serrated ovipositor, eggs are laid in preharvest fruit, causing large economic losses in cultivated berries and stone fruit. Modeling D. suzukii population dynamics and potential distribution will require information on its thermal tolerance. Large summer populations have been found in regions with severe winter conditions, though little is known about responses to prolonged low-temperature exposure. We used controlled chambers to examine D. suzukii fecundity, development rate, and mortality across a range of temperatures encompassing the upper and lower thresholds (5-35 • C). Optimal temperatures (T opt ) were found to be 28.2 • C for the development of the egg-to-adult stage, and 22.9 • C for reproductive output. No adult eclosion occurred below 8.1 • C (T lower ) or above 30.9 • C (T upper ). We also investigated survival outcomes following prolonged (42-d) low-temperature exposure to a simulated cold winter (−5, −3, −1, 1, 3, and 5 • C). Adult survival was dependent on temperature, with a mean LT 50 of 4.9 • C. There were no effects of sex, mating status, geographic strain, and photoperiod preexposure on overwintering survival. Thirty-eight percent of females that were mated prior, but not after, prolonged low-temperature exposure produced viable offspring, suggesting that this species may undergo sperm storage. This study provides data on the thermal tolerances of D. suzukii, which can be used for models of D. suzukii population dynamics, degree-day, and distribution models.
a b s t r a c tThe leatherback, Dermochelys coriacea, is a large sea turtle that feeds primarily on jellyfish. Floating plastic garbage could be mistaken for such prey. Autopsy records of 408 leatherback turtles, spanning 123 years , were studied for the presence or absence of plastic in the GI tract. Plastic was reported in 34% of these cases. If only cases from our first report (1968) of plastic were considered, the figure was 37%. Blockage of the gut by plastic was mentioned in some accounts. These findings are discussed in the context of removal of top predators from poorly understood food chains.
Summary1. Cool-season grasses can be simultaneously infected by foliar fungal endophytes and colonised by mycorrhizal fungi, the integrated functions of which are strong predictors of plant fitness within grassland ecosystems. Evidence has been presented previously that infection of grass species with foliar endophytes can negatively affect mycorrhizal colonisation. Here, we tested the hypothesis that mycorrhizal colonisation in turn adversely affects Neotyphodium endophyte concentrations and that the competitive interaction between the two endosymbionts is affected by resource supply. 2. Specifically, we report how competition between Glomus (G. mosseae -GM, G. intraradices -GI) mycorrhizal fungi and N. lolii (common strain (CS) and AR1) foliar endophytic strains is affected by P supply and water-soluble carbohydrate (WSC) content in two Lolium perenne (perennial ryegrass) cultivars: a high sugar grass, AberDart, and a conventional (control) grass, Fennema. 3. The presence of Glomus mycorrhizae reduced the concentrations of endophytes and alkaloids in leaf blades and pseudostems. The reduction depended on P supply, ryegrass cultivar (notably WSC content) and endophyte strain. Conversely, foliar endophyte infection reduced mycorrhizal colonisation rates and concentrations in the roots of the control cultivar Fennema, although not in the high sugar cultivar, AberDart. 4. Neither GM nor N. lolii infection had an effect per se on the yield of root or blade compared with mycorrhiza-free (M-) and endophyte-free (E-) plants, respectively; though, yield of roots and blades was reduced by GI infection and at low P. 5. Competitive interactions between ecologically widespread foliar endophytes (valuable for plant protection) and mycorrhizal endosymbionts (valuable for P acquisition) as seen in this study are of critical importance especially in areas of high pest prevalence and low P availability. Our work stresses the need for elucidating the physiological ⁄ metabolic basis for such interactions between endosymbionts to understand how these processes contribute to plant performance and fitness in grassland ecosystems.
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