Sustainable production of 2,5-diformylfuran via peroxymonosulfate-triggered mild catalytic oxidation of lignocellulosic biomass.

The relentless depletion of fossil fuels accentuates the urgent necessity for the sustainable synthesis of chemicals from renewable biomass. 5-Hydroxymethylfurfural (HMF), extracted from lignocellulosic biomass, emerges as a beacon of hope for conversion into value-added chemicals. However, the inherent susceptibility of its unsaturated aldehyde groups to excessive oxidation often culminates in undesired reactions, compromising both the yield and specificity of the desired products.

Seasonal Migration Patterns of Ostrinia furnacalis (Lepidoptera: Crambidae) Across the Bohai Strait in Northern China.

The Asian corn borer (ACB), Ostrinia furnacalis (Guenée), is a notorious polyphagous insect pest in China and other regions of East Asia. The long-distance flight behavior of the ACB moths, however, is not well understood, especially in the field conditions. In this study, nightly monitoring data for multiple years (2003-2017) on the long-distance flight of adults crossing the Bohai Strait in northern China, showed that a large number of the adults frequently flew across the Bohai Strait from May to September with the peak migrations usually occurred, followed in order by September, June, July, and May, and the number of southward migrants was larger than that of northward migrants.

Seasonal Migration Pattern of Nilaparvata lugens (Hemiptera: Delphacidae) Over the Bohai Sea in Northern China.

The brown planthopper Nilaparvata lugens (Stål) (Hemiptera: Delphacidae) is a major, regionally migratory pest of rice crops in Asia. Despite intensive studies, the seasonal pattern of migration in this species remains largely unknown, especially in northern China. Analysis of monitoring data of light trapping at Beihuang island in northern China showed that brown planthopper migrants could be found at the island in any month from July to October.

Hybridizing transgenic Bt cotton with non-Bt cotton counters resistance in pink bollworm.

Extensive cultivation of crops genetically engineered to produce insecticidal proteins from the bacterium (Bt) has suppressed some major pests, reduced insecticide sprays, enhanced pest control by natural enemies, and increased grower profits. However, these benefits are being eroded by evolution of resistance in pests. We report a strategy for combating resistance by crossing transgenic Bt plants with conventional non-Bt plants and then crossing the resulting first-generation (F) hybrid progeny and sowing the second-generation (F) seeds.

Enhanced stability in host-parasitoid interactions with autoparasitism and parasitoid migration.

Previous studies based on simple non-spatial model have suggested that autoparasitism, in which females develop as primary endoparasitoids of hosts while males develop at the expense of primary parasitoids, stabilizes host-parasitoid steady state. To date, however, how the stabilizing role of autoparasitism would be affected by more complex spatial factors has not been adequately investigated. To address the issue, here we analyzed a spatially extended two-patch host-parasitoid model and compared it with the corresponding non-spatial model.

Diminishing returns from increased percent Bt cotton: the case of pink bollworm.

Regional suppression of pests by transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt) has been reported in several cropping systems, but little is known about the functional relationship between the ultimate pest population density and the pervasiveness of Bt crops. Here we address this issue by analyzing 16 years of field data on pink bollworm (Pectinophora gossypiella) population density and percentage of Bt cotton in the Yangtze River Valley of China. In this region, the percentage of cotton hectares planted with Bt cotton increased from 9% in 2000 to 94% in 2009 and 2010.

Population impacts of Wolbachia on Aedes albopictus.

Prior studies have demonstrated that Wolbachia, a commonly occurring bacterium capable of manipulating host reproduction, can affect life history traits in insect hosts, which in turn can have population-level effects. Effects on hosts at the individual level are predicted to impact population dynamics, but the latter has not been examined empirically. Here, we describe a biological model system based on Aedes albopictus (Asian tiger mosquito) that allows for measurement of population dynamics, which has not been accomplished in prior field trials or laboratory designs.

The halo effect: suppression of pink bollworm on non-Bt cotton by Bt cotton in China.

In some previously reported cases, transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt) have suppressed insect pests not only in fields planted with such crops, but also regionally on host plants that do not produce Bt toxins. Here we used 16 years of field data to determine if Bt cotton caused this "halo effect" against pink bollworm (Pectinophora gossypiella) in six provinces of the Yangtze River Valley of China. In this region, the percentage of cotton hectares planted with Bt cotton increased from 9% in 2000 to 94% in 2009 and 2010.

Increased frequency of pink bollworm resistance to Bt toxin Cry1Ac in China.

Transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt) kill some key insect pests, but evolution of resistance by pests can reduce their efficacy. The main approach for delaying pest adaptation to Bt crops uses non-Bt host plants as "refuges" to increase survival of susceptible pests. To delay evolution of pest resistance to transgenic cotton producing Bt toxin Cry1Ac, the United States and some other countries have required refuges of non-Bt cotton, while farmers in China have relied on "natural" refuges of non-Bt host plants other than cotton.

Wolbachia infections that reduce immature insect survival: predicted impacts on population replacement.

Background: The evolutionary success of Wolbachia bacteria, infections of which are widespread in invertebrates, is largely attributed to an ability to manipulate host reproduction without imposing substantial fitness costs. Here, we describe a stage-structured model with deterministic immature lifestages and a stochastic adult female lifestage. Simulations were conducted to better understand Wolbachia invasions into uninfected host populations.

Gene-drive into insect populations with age and spatial structure: a theoretical assessment.

The potential benefits and risks of genetically engineered gene-drive systems for replacing wild pest strains with more benign strains must be assessed prior to any field releases. We develop a computer simulation model to assess the feasibility of using engineered underdominance constructs to drive transgenes into age- and spatially structured mosquito populations. Our practical criterion for success is the achievement of a transgene frequency of at least 0.

Medea selfish genetic elements as tools for altering traits of wild populations: a theoretical analysis.

One strategy for controlling transmission of insect-borne disease involves replacing the native insect population with transgenic animals unable to transmit disease. Population replacement requires a drive mechanism to ensure the rapid spread of linked transgenes, the presence of which may result in a fitness cost to carriers. Medea selfish genetic elements have the feature that when present in a female, only offspring that inherit the element survive, a behavior that can lead to spread.

Density-dependent intraspecific competition in the larval stage of Aedes aegypti (Diptera: Culicidae): revisiting the current paradigm.

Density-dependent intraspecific competition has been considered an important determinant of the dynamics of larval stages of Aedes aegypti. A model was published in 1984 providing a mathematical description of this density dependence, based on field data, that has since been widely used. This description, however, is based on the strong assumption that all mortality is density-dependent.

Gene-drive in age-structured insect populations.

To date, models of gene-drive mechanisms proposed for replacing wild-type mosquitoes with transgenic strains that cannot transmit diseases have assumed no age or mating structure. We developed a more detailed model to analyze the effects of age and mating-related factors on the number of engineered insects that must be introduced into a wild population to achieve successful gene-drive based on the Medea and engineered underdominance mechanisms. We found that models without age-structure and mating details can substantially overestimate or underestimate the numbers of engineered insects that must be introduced.

A killer-rescue system for self-limiting gene drive of anti-pathogen constructs.

A number of genetic mechanisms have been suggested for driving anti-pathogen genes into natural populations. Each of these mechanisms requires complex genetic engineering, and most are theoretically expected to permanently spread throughout the target species' geographical range. In the near term, risk issues and technical limits of molecular methods could delay the development and use of these mechanisms.

Introducing transgenes into insect populations using combined gene-drive strategies: modeling and analysis.

Engineered underdominance (EU), meiotic drive (MD) and Wolbachia have been proposed as mechanisms for driving anti-pathogen transgenes into natural populations of insect vectors of human diseases. EU can drive transgenes to high and stable frequencies but requires the release of sizeable numbers of engineered insects. MD and Wolbachia either cannot maintain high frequencies of transgenes or lack appropriate expression in critical tissues, but both can drive the transgenes to spread from very low initial frequencies.

Introducing desirable transgenes into insect populations using Y-linked meiotic drive - a theoretical assessment.

The use of genetic drive mechanisms to replace native mosquito genotypes with individuals bearing antipathogen transgenes is a potential strategy for repressing insect transmission of human diseases such as malaria and dengue. Antipathogen transgenes have been developed and tested, but efficient gene drive mechanisms are lacking. Here we theoretically assess the feasibility of introducing antipathogen genes into wild Aedes aegypti populations by using a naturally occurring meiotic drive system.

Age-structured effects and disease interference in childhood infections.

Recent studies have demonstrated that ecological interference among some childhood diseases may have important dynamic consequences. An interesting question is, when would we expect the interference effect to be pronounced? To address the issue, here we develop a seasonally forced two-disease age-structured model, using empirically derived age-specific force of infection (ASFOI) for numerous infections of childhood. Our comparative numerical analysis shows that when the ASFOIs for the two diseases largely overlap, the dynamics predicted by the two-disease model are generally different from those predicted by the analogous single-disease model, suggesting strong fingerprints of disease interference.

The dynamical implications of disease interference: correlations and coexistence.

Ecological interference between unrelated diseases, caused by the temporary or permanent removal of individuals susceptible to one disease following infection with another, might be an important mechanism underlying epidemics. In this paper, we explore the potential dynamic consequences of interference by analyzing a two-disease model. By studying the stability domain of the model's equilibria, we find that the stable region of the two-disease endemic state becomes increasingly smaller as the strength of interference (largely determined by the disease-induced mortality) increases.

How do cross-migration models arise?

In this paper we present a general method to derive spatio-temporal population models mechanistically. We consider a system of multiple species living in a patchy habitat in which the local population of each species consists of some behavioural groups. We then formulate a continuous-time model where a small positive parameter is present, measuring the time scale of behavioural transitions relative to that of giving birth, death and migration among patches.

Double-Jump migration and diffusive instability.

In order to look into the stability consequences of a particular migration process in which individuals choose to settle, we formulated a continuous-time multi-species multi-patch model in which individuals migrate by one or two instantaneous jumps while making the second jump with a certain probability that possibly depends on the conditions at the end point of the first jump. It turned out that a second jump has some quantitative effects on diffusive instability even when it occurs in the absence of density-dependent mechanisms. When a second jump happens as a natural interspecific response of individuals, and such a response is sufficiently strong, it has crucial effects on diffusive instability: it leads to diffusive instability in the case of competitive interactions, whereas it annihilates diffusive instability in the case of prey-predator interactions.

Interspecific influence on mobility and Turing instability.

In this paper we formulate a multi-patch multi-species model in which the per-capita emigration rate of one species depends on the density of some other species. We then focus on Turing instability to examine if and when this cross-emigration response has crucial effects. We find that the type of interaction matters greatly.