Atmospheric warming, combined with projected atmospheric carbon dioxide (ab. CO2) level arising, may have marked ecological effects on growth of agricultural crop plants, and in turn affect the higher trophic level of insect herbivores. In this study, the effects of elevated CO2 (i.e., 650 μL/L vs. ambient 400 μL/L) and temperature (ab. T; ambient vs. ambient +0.6°C) on the population abundance and the interspecific competition among three co‐occurring species of wheat aphids (Sitobion avenae, Rhopalosiphum padi and Schizaphis graminum) were studied. The results indicated that wheat plants had higher biomass and yields when grown under elevated CO2 in contrast to ambient CO2, and elevated T had no significant effect on the biomass and yields of wheat plants. Elevated CO2 significantly decreased the population dynamic level of S. avenae, and increased the population dynamic levels of R. padi and S. graminum; Elevated T significantly decreased the population dynamic level of S. avenae and significantly increased the population dynamic level of R. padi. Moreover, elevated T significantly decreased the niche breadth of S. avenae and S. graminum, respectively, while elevated CO2 had no significant effect on the three species niche breadth. Furthermore, elevated CO2 and T both significantly increased the niche overlap index (ab. NOI) between S. avenae and R. padi, as well as between R. padi and S. graminus, elevated T significantly reduced the NOI between S. avenae and S. graminus. This study provides evidence that elevated CO2 and T can alter the species‐specific population abundance of three wheat aphids, and aggravate two major interspecific competition among these three co‐occurring species of wheat aphids by increasing their spatial overlap.

The widespread planting of insect-resistant crops has caused a dramatic shift in agricultural landscapes, thus raising concerns about the potential impacts on both target and non-target pests. In this study, we examined the potential effects of intra-specific seed mixture sowing with transgenic Bt rice (Bt) and its parental non-transgenic line (Nt) (100% Bt rice [Bt ], 5% Nt+95% Bt [Nt Bt ], 10% Nt+90% Bt [Nt Bt ], 20% Nt+80% Bt [Nt Bt ], 40% Nt+60% Bt [Nt Bt ] and 100% Nt rice [Nt ]) on target and non-target pests in a 2-year field trial in southern China. The occurrence of target pests, Sesamia inferens, Chilo suppressalis and Cnaphalocrocis medinalis, decreased with the increased ratio of Bt rice, and the mixture ratios with more than 90% Bt rice (Bt and Nt Bt ) significantly increased the pest suppression efficiency, with the lowest occurrences of non-target planthoppers, Nilaparvata lugens and Sogatella furcifera in Nt and Nt Bt . Furthermore, there were no significant differences in 1000-grain dry weight and grain dry weight per 100 plants between Bt and Nt Bt . Seed mixture sowing of Bt rice with ≤10% (especially 5%) of its parent line was sufficient to overcome potential compliance issues that exist with the use of block or structured refuge to provide most effective control of both target and non-target pests without compromising the grain yield. It is also expected that the strategy of seed mixture sowing with transgenic Bt rice and the non-transgenic parental line would provide rice yield stability while decreasing the insecticide use frequency in rice production.

Five soil samples in different depths of a site in the close vicinity of a Wuhan iron and steel factory (Core 1) were collected. One uncontaminated soil profile (Core 2) was taken for reference purpose. The soil arsenic content and speciation vertical distribution patterns were analyzed by inductively coupled plasma-mass spectrometry, and BCR sequential extraction protocol. The results showed that the arsenic content in Core 1 was remarkably higher than Core 2 in same depth, which indicated that microbial communities were very sensitively to indicate arsenic distribution and toxicity. Additionally, principal component analyses also revealed that the arsenic exchangeable fraction play an important role to indicate arsenic ecotoxicity in mining soil and sediment.