Predator-induced stress influences fall armyworm immune response to inoculating bacteria.

The insect innateimmunesystem is assorted into two general categories, cellular and humoral immunity. Aside from direct challenge by invaders, predation risk can be perceived as odors, sounds or nearness. In this study, we evaluated influence of predation risk by the predatory bug Podisus maculiventris on immunity of an herbivore Spodoptera frugiperda. Under the predator-induced stress combined with Escherichia coli inoculation, several larval physiological parameters of S. frugiperda were studied, including body mass, nodulation, and phenoloxidase activity. Our findings offernew evidence that provides insight into the immunological mechanism of predator-induced stress effects on prey species.

Agricultural diversification promotes sustainable and resilient global rice production.

Rice is a staple food for half of the human population, but the effects of diversification on yields, economy, biodiversity and ecosystem services have not been synthesized. Here we quantify diversification effects on environmental and socio-economic aspects of global rice production. We performed a second-order meta-analysis based on 25 first-order meta-analyses covering four decades of research, showing that diversification can maintain soil fertility, nutrient cycling, carbon sequestration and yield. We used three individual first-order meta-analyses based on 39 articles to close major research gaps on the effects of diversification on economy, biodiversity and pest control, showing that agricultural diversification can increase biodiversity by 40%, improve economy by 26% and reduce crop damage by 31%. Trade-off analysis showed that agricultural diversification in rice production promotes win-win scenarios between yield and other ecosystem services in 81% of all cases. Knowledge gaps remain in understanding the spatial and temporal effects of specific diversification practices and trade-offs.

Field response of aboveground non-target arthropod community to transgenic Bt-Cry1Ab rice plant residues in postharvest seasons.

Risk assessments of ecological effects of transgenic rice expressing lepidoptera-Cry proteins from Bacillus thuringiensis (Bt) on non-target arthropods have primarily focused on rice plants during cropping season, whereas few studies have investigated the effects in postharvest periods. Harvested rice fallow fields provide a critical over-wintering habitat for arthropods in the Chinese rice ecosystems, particularly in the southern region of the country. During 2006-08, two independent field trials were conducted in Chongqing, China to investigate the effects of transgenic Cry1Ab rice residues on non-target arthropod communities. In each trial, pitfall traps were used to sample arthropods in field plots planted with one non-Bt variety and two Bt rice lines expressing the Cry1Ab protein. Aboveground arthropods in the trial plots during the postharvest season were abundant, while community densities varied significantly between the two trials. A total of 52,386 individual insects and spiders, representing 93 families, was captured in the two trials. Predominant arthropods sampled were detritivores, which accounted for 91.9% of the total captures. Other arthropods sampled included predators (4.2%), herbivores (3.2%), and parasitoids (0.7%). In general, there were no significant differences among non-Bt and Bt rice plots in all arthropod community-specific parameters for both trials, suggesting no adverse impact of the Bt rice plant residues on the aboveground non-target arthropod communities during the postharvest season. The results of this study provide additional evidence that Bt rice is safe to non-target arthropod communities in the Chinese rice ecosystems.

Effects of transgenic Bt rice on growth, reproduction, and superoxide dismutase activity of Folsomia candida (Collembola: Isotomidae) in laboratory studies.

Transgenic rice expressing Bacillus thuringiensis (Bt) CrylAb protein is expected to be commercialized in China in the near future. The use of Bt rice for controlling insect pests sparks intensive debates regarding its biosafety. Folsomia candida is an euedaphic species and is often used as a "standard" test organism in assessing effects of environmental pollutants on soil organisms. In this study, growth, development, reproduction, and superoxide dismutase activity (SOD) of F. candida were investigated in the laboratory for populations reared on leaf tissue or leaf-soil mixtures of two CrylAb rice lines and a non-Bt rice isoline. Two independent tests were performed: 1) a 35-d test using petri dishes containing yeast diet (positive control) or fresh rice leaf tissue, and 2) a 28-d test in soil-litter microcosms containing yeast or a mixture of soil and rice leaf tissue. Biological parameters measured in both tests were number of progeny production, population growth rate, and SOD activity. For the petri dish test, data measured also included insect body length and number of exuviation. There were no significant differences between the populations reared on Bt and non-Bt rice leaf tissue in all measured parameters in both tests and for both Bt rice lines, suggesting no significant effects of the CrylAb protein in Bt rice on F. candida in the laboratory studies. Results of this study should add additional biosafety proofs for use of Bt rice to manage rice pests in China.

[Growth response of coniferous trees to climate change in the Qinling Mountains, China]. / ç§¦å²­å±±åœ°é’ˆå¶æ ‘ç§æ ‘æœ¨ç”Ÿé•¿å¯¹æ°”å€™å˜åŒ–çš„å“åº”.

As an important geographical boundary, the subalpine coniferous forests in the Qinling Mountains have critical effects on water conservation, biodiversity conservation and climate regulation at the regional and even larger scale. In recent decades, temperature significantly increased in the Qinling Mountains, with significant spatial heterogeneity. An understanding of the responses of the Qinling coniferous trees to climate change is important for the protection and management of mountain forests under climate change. In this study, we synthesized the relationships between the radial growth of coniferous trees and climate at different altitudes in the western, central, and eas-tern Qinling Mountains. The effects of climate change on coniferous trees were investigated from the aspects of radial growth, NDVI, phenology, and species distribution range. Furthermore, know-ledge gaps in the responses of tree growth to climate change and possible future directions in this field were discussed.

Occurrence and larval movement of Diatraea saccharalis (Lepidoptera: Crambidae) in seed mixes of non-Bt and Bt pyramid corn.

BACKGROUND: Larval movement of target pest populations among Bt and non-Bt plants is a major concern in the use of a seed mixture refuge strategy for Bt resistance management. In this study, occurrence and larval movement of the sugarcane borer, Diatraea saccharalis (F.), were evaluated in four planting patterns of non-Bt and Bt plants containing Genuity® SmartStax(TM) traits in 2009-2011. The four planting patterns were: (1) a pure stand of 27 Bt plants; (2) one non-Bt plant in the center, surrounded by 26 Bt plants; (3) a pure stand of 27 non-Bt plants; (4) one Bt plant in the center, surrounded by 26 non-Bt plants. Studies were conducted under four conditions: (1) open field with natural infestation; (2) greenhouse with artificial infestations; open field with artificial infestations (3) on the center plants only and (4) on every plant. The major objective of this study was to determine whether refuge plants in a seed mixture strategy could provide a comparable refuge population of D. saccharalis to a 'structured refuge' planting. RESULTS: Larvae of D. saccharalis showed the ability to move from infested plants to at least four plants away, as well as to adjacent rows, but the majority remained within the infested row. However, the number of larvae found on the non-Bt plants in the mixture plantings was not significantly reduced compared with the pure stand of non-Bt corn. CONCLUSION: The results of this study show that refuge plants in a seed mixture may be able to provide a comparable refuge population of D. saccharalis to a structured refuge planting.

[Effects of transgenic Bt cry1Ab rice on collembolan population in paddy field].

To assess the potential ecological risk of transgenic Bt rice to non-target soil organisms in paddy field, transgenic crylAb rice KMD1 and KMD2 and their parental control rice line XS11 were planted in experimental fields, and collembolan species and their densities were investigated during grain-filling and post-harvest stages in 2003 to approximately 2004. By using an arthropod-sucking machine, two collembolan species, Entomobrya griseoolivata and Bourletiella christianseni, were collected from the leaf litter at soil surface during grain-filling stage (September,2003), and the population densities of E. griseoolivata in KMD1 and KMD2 paddy fields were significantly higher than those in XS11 paddy field. With bags contained rice stem-leaf litter and initially placed in the paddy field at harvest time (November,2003), four collembolan species, E. griseoolivata, B. christianseni, Hypogastrura matura and Isotoma monochaeta, were collected during post-harvest stages (April, 2004), and the densities of E. griseoolivata and H. matura in KMD1 and KMD2 paddy fields were also significantly higher than those in XS11 paddy field. The biomass loss of KMD1 and KMD2 stem-leaf litter was significantly greater than that of XS11's.

[Advances in safety studies of soil Bt toxin proteins released from transgenic Bt crops].

Commercialized transgenic Bt (Bacillus thuringiensis) crops are permitted for field growth in a large scale, which leads to significant issues of ecological risk assessment in soil ecosystem. In this paper, some general safety problems involving in the soil Bt active toxins released from insect-resistant transgenic Bt crops in the forms of plant residues, root exudates and pollens were reviewed, including their adsorption by soil active-particles, their insecticidal activity, persistence, and biodegradation by soil microbes, and their effects on soil organisms.