scholarly journals Shifts in Ecological Dominance between Two Lepidopteran Species in Refuge Areas of Bt Cotton

Insects ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 157 ◽  
Author(s):  
José Bruno Malaquias ◽  
Danilo Renato Santiago Santana ◽  
Paulo Eduardo Degrande ◽  
Claudia Pio Ferreira ◽  
Elmo Pontes de Melo ◽  
...  
Keyword(s):  
Game Theory ◽  
Large Scale ◽  
Phenotypic Diversity ◽  
Food Resource ◽  
Data Matrix ◽  
Bt Cotton ◽  
Pest Species ◽  
Resistance Evolution ◽  
Ecological Dominance ◽  
Refuge Areas

Competition behavior involving agricultural pest species has long been viewed as a powerful selective force that drives ecological and phenotypic diversity. In this context, a Game Theory-based approach may be useful to describe the decision-making dilemma of a competitor with impacts to guarantee its superiority in terms of ecological dominance or sharing of the food resource with its competitor. In an attempt to elucidate the consequences of competitive dynamics for the ecological dominance of these species in refuge areas of Bt cotton, we conducted a study that was divided into two parts. The first study consisted of an evaluation of interactions involving Spodoptera frugiperda (JE Smith, 1797) and Helicoverpa armigera (Hübner, 1808) on non-Bt cotton plants in a field trial. In the second study, we explored the data matrix collected in the field to parameterize a model of Cellular Automata (CA) with update rules inspired by Game Theory. Computer simulations were analyzed in hypothetical scenarios involving the application (or not) of insecticides in the refuge areas in combination with the resistance factor of one or both pest species to the insecticides used in the refuge areas. H. armigera had superior competitive performance in relation to S. frugiperda only at high densities. According to the density-mediated shift in dominance of the species, the resistance of S. frugiperda to insecticides is seen as a risk factor for the production of susceptible individuals of H. armigera on a large scale in the refuge areas. Additionally, S. frugiperda insecticide resistance may potentially impact the resistance evolution of the H. armigera population to Bt cotton. Thus, ecological dominance could diverge by the presence of a resistance allele to insecticides with interspecific competition perhaps subordinate to evolutionary processes.

Experimental and theoretical landscape influences on Spodoptera frugiperda movement and resistance evolution in contaminated refuge areas of Bt cotton

2019 ◽  
Vol 93 (1) ◽  
pp. 329-340 ◽  
Author(s):  
José Bruno Malaquias ◽  
Michael A. Caprio ◽  
Wesley A. C. Godoy ◽  
Celso Omoto ◽  
Francisco S. Ramalho ◽  
...  
Keyword(s):  
Spodoptera Frugiperda ◽  
Bt Cotton ◽  
Resistance Evolution ◽  
Refuge Areas ◽  
Landscape Influences

scholarly journals Large-scale assessment of lepidopteran soybean pests and efficacy of Cry1Ac soybean in Brazil

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Renato J. Horikoshi ◽  
Patrick M. Dourado ◽  
Geraldo U. Berger ◽  
Davi de S. Fernandes ◽  
Celso Omoto ◽  
...  
Keyword(s):  
Large Scale ◽  
Anticarsia Gemmatalis ◽  
Pest Species ◽  
Large Scale Assessment ◽  
Resistance Evolution ◽  
Lepidopteran Pests ◽  
High Level ◽  
Lepidopteran Pest ◽  
Insecticide Sprays ◽  
Chrysodeixis Includens

AbstractThe soybean technology MON 87701 × MON 89788, expressing Cry1Ac and conferring tolerance to glyphosate, has been widely adopted in Brazil since 2013. However, pest shifts or resistance evolution could reduce the benefits of this technology. To assess Cry1Ac soybean performance and understand the composition of lepidopteran pest species attacking soybeans, we implemented large-scale sampling of larvae on commercial soybean fields during the 2019 and 2020 crop seasons to compare with data collected prior to the introduction of Cry1Ac soybeans. Chrysodeixis includens was the main lepidopteran pest in non-Bt fields. More than 98% of larvae found in Cry1Ac soybean were Spodoptera spp., although the numbers of Spodoptera were similar between Cry1Ac soybean and non-Bt fields. Cry1Ac soybean provided a high level of protection against Anticarsia gemmatalis, C. includens, Chloridea virescens and Helicoverpa spp. Significant reductions in insecticide sprays for lepidopteran control in soybean were observed from 2012 to 2019. Our study showed that C. includens and A. gemmatalis continue to be primary lepidopteran pests of soybean in Brazil and that Cry1Ac soybean continues to effectively manage the target lepidopteran pests. However, there was an increase in the relative abundance of non-target Spodoptera spp. larvae in both non-Bt and Cry1Ac soybeans.

scholarly journals Kernel weighted least square approach for imputing missing values of metabolomics data

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nishith Kumar ◽  
Md. Aminul Hoque ◽  
Masahiro Sugimoto
Keyword(s):  
Missing Data ◽  
Large Scale ◽  
Missing Values ◽  
Kernel Weight ◽  
Least Square ◽  
Data Matrix ◽  
Data Imputation ◽  
Metabolomics Data ◽  
Missing Value ◽  
Missing Data Imputation

AbstractMass spectrometry is a modern and sophisticated high-throughput analytical technique that enables large-scale metabolomic analyses. It yields a high-dimensional large-scale matrix (samples × metabolites) of quantified data that often contain missing cells in the data matrix as well as outliers that originate for several reasons, including technical and biological sources. Although several missing data imputation techniques are described in the literature, all conventional existing techniques only solve the missing value problems. They do not relieve the problems of outliers. Therefore, outliers in the dataset decrease the accuracy of the imputation. We developed a new kernel weight function-based proposed missing data imputation technique that resolves the problems of missing values and outliers. We evaluated the performance of the proposed method and other conventional and recently developed missing imputation techniques using both artificially generated data and experimentally measured data analysis in both the absence and presence of different rates of outliers. Performances based on both artificial data and real metabolomics data indicate the superiority of our proposed kernel weight-based missing data imputation technique to the existing alternatives. For user convenience, an R package of the proposed kernel weight-based missing value imputation technique was developed, which is available at https://github.com/NishithPaul/tWLSA.

Entangled Systems at the Energy-Water-Food Nexus

2017 ◽  
pp. 144-165
Author(s):  
Joseph Nyangon ◽  
Nabeel Alabbas ◽  
Lawrence Agbemabiese
Keyword(s):  
Large Scale ◽  
Food Resource ◽  
Institutional Processes ◽  
Trade Offs ◽  
Institutional Structures ◽  
Private And Public ◽  
Energy Economy ◽  
Political Economic ◽  
Resource Systems

This chapter assesses energy, water, and food resource systems based on their inter- and intra-sectoral imperatives of large scale development investments at the institutional level (including private and public activities) and how to achieve security of resource supplies. It identifies key interrelated processes, practices, and factors that underpin integrated resource management (IRM) and their attendant benefits. Applying the E4 framework concerned with energy, economy, environment, and equity to identify the main threats to these systems, the chapter evaluates their institutional, political, economic, cultural and behavioral components, and characterizes the forces that drive each of them at different governance scales. The chapter is guided by political economy, economic, and sociological theories that suggest that institutional structures affect economic factors and processes (i.e. production, distribution, and consumption processes). A case study of energy, water, and food (EWF) conflicting sectoral imperatives in Delaware is discussed in detail to better understand how these policy and institutional processes occur, which forms they take, and in which ways they define the quality and quantity of EWF resource systems in the State. In order to verify these parameters, the analysis considered the advantages of a sectorally balanced, E4 framework, in particular to evaluate the valency and magnitude of cross-sectoral connections, balance competing needs, and identify policy options that address various trade-offs.

scholarly journals The level of Cry1Ac endotoxin and its efficacy against H. armigera in Bt cotton at large scale in Pakistan

2020 ◽  
Vol 12 (1) ◽  
pp. 1-17 ◽  
Author(s):  
Shakra Jamil ◽  
Rahil Shahzad ◽  
Sajid Ur Rahman ◽  
Muhammad Zaffar Iqbal ◽  
Muhammad Yaseen ◽  
...  
Keyword(s):  
Large Scale ◽  
Bt Cotton

scholarly journals Canopy cover and anurans: nutrients are the most important predictor of growth and development

2016 ◽  
Vol 94 (3) ◽  
pp. 225-232 ◽  
Author(s):  
Freya E. Rowland ◽  
Sara K. Tuttle ◽  
María J. González ◽  
Michael J. Vanni
Keyword(s):  
Growth And Development ◽  
Large Scale ◽  
Food Resource ◽  
Canopy Cover ◽  
Resource Quality ◽  
Bottom Up ◽  
Growth And Survival ◽  
Primary Producer ◽  
Full Factorial ◽  
Potential Food

Bottom-up effects such as the availability of light and nutrients can have large impacts on primary producer quantity and quality, which is then translated into the growth and development of consumers. The use of “canopy cover” as a bottom-up predictive factor is a broad categorization, as canopy cover controls both the amount of light allowed into a pond and the nutrient load through leaf litter. To test how light and nutrients influence pond ecosystems, we manipulated inorganic nutrients and light in a 2 × 3 full-factorial, large-scale mesocosm experiment. Larval American Bullfrogs (Lithobates catesbeianus (Shaw, 1802)) were reared for 6 weeks at low densities and then assessed for development, growth, and survival at the end of the experiment. We also collected weekly samples of potential food resources (phytoplankton and periphyton) for the estimation of algal production and stoichiometric quality (carbon:nitrogen:phosphorus). Light had strong effects on food resource quality; however, resource quality did not significantly predict tadpole growth or development. Instead, nutrients seemed to be the most important factor as a stimulator of total algal primary production and some unknown pathway, which in turn affected tadpole development. Ours is the first study to investigate canopy cover using a comprehensive causal model, and our results suggest in regards to tadpole growth and development, canopy cover is important mainly as a source of nutrients to ponds.

scholarly journals Molecular identification of the swede midge (Diptera: Cecidomyiidae)

2004 ◽  
Vol 136 (6) ◽  
pp. 771-780 ◽  
Author(s):  
Juerg E. Frey ◽  
Beatrice Frey ◽  
Robert Baur
Keyword(s):  
Large Scale ◽  
Crop Protection ◽  
Adult Life ◽  
Molecular Diagnostic ◽  
Pest Species ◽  
Adult Life Span ◽  
Protection Measures ◽  
Major Pest ◽  
Swede Midge ◽  
Species Specific

AbstractEarly detection of pest infestation is a prerequisite for sustainable crop protection. However, many pest species are difficult to detect and thus infestation is diagnosed from damage observed on the respective crop. This diagnosis is often made too late for implementation of crop protection measures, and serious crop losses may result. The swede midge, Contarinia nasturtii Kieffer, is a major pest of Brassica L. (Brassicaceae) vegetables in Europe that has recently invaded North America. With its small size and short adult life-span, and the cryptic lifestyle of the larvae feeding at the growing points of its host plants, it is usually detected only after damage has already occurred. Furthermore, because field-trapped specimens are rarely fully intact, it is extremely difficult to identify. Therefore, we developed a species-specific molecular diagnostic method that enables reliable identification of swede midge from various sources such as alcohol or sticky glue traps. The method enables large-scale screening of field-trapped specimens and is used to evaluate the attractiveness and specificity of pheromone traps that are currently under development.

scholarly journals Computational biomechanics changes our view on insect head evolution

2017 ◽  
Vol 284 (1848) ◽  
pp. 20162412 ◽  
Author(s):  
Alexander Blanke ◽  
Peter J. Watson ◽  
Richard Holbrey ◽  
Michael J. Fagan
Keyword(s):  
Large Scale ◽  
Biomechanical Model ◽  
Morphological Characters ◽  
Data Matrix ◽  
Morphological Data ◽  
Character State ◽  
Functional Dependencies ◽  
Element Analysis ◽  
Computational Biomechanics ◽  
Relationship Of

Despite large-scale molecular attempts, the relationships of the basal winged insect lineages dragonflies, mayflies and neopterans, are still unresolved. Other data sources, such as morphology, suffer from unclear functional dependencies of the structures considered, which might mislead phylogenetic inference. Here, we assess this problem by combining for the first time biomechanics with phylogenetics using two advanced engineering techniques, multibody dynamics analysis and finite-element analysis, to objectively identify functional linkages in insect head structures which have been used traditionally to argue basal winged insect relationships. With a biomechanical model of unprecedented detail, we are able to investigate the mechanics of morphological characters under biologically realistic load, i.e. biting. We show that a range of head characters, mainly ridges, endoskeletal elements and joints, are indeed mechanically linked to each other. An analysis of character state correlation in a morphological data matrix focused on head characters shows highly significant correlation of these mechanically linked structures. Phylogenetic tree reconstruction under different data exclusion schemes based on the correlation analysis unambiguously supports a sistergroup relationship of dragonflies and mayflies. The combination of biomechanics and phylogenetics as it is proposed here could be a promising approach to assess functional dependencies in many organisms to increase our understanding of phenotypic evolution.

Response of a floodplain fish community to river-floodplain connectivity: natural versus managed reconnection

2014 ◽  
Vol 71 (2) ◽  
pp. 236-245 ◽  
Author(s):  
R.J. Stoffels ◽  
K.R. Clarke ◽  
R.A. Rehwinkel ◽  
B.J. McCarthy
Keyword(s):  
Native Species ◽  
Fish Community ◽  
Large Scale ◽  
Environmental Flows ◽  
Regulated River ◽  
Pest Species ◽  
Fish Community Structure ◽  
River Floodplain ◽  
Natural Connection ◽  
Flood Pulses

To restore lateral connectivity in highly regulated river-floodplain systems, it has become necessary to implement localized, “managed” connection flows, made possible using floodplain irrigation infrastructure. These managed flows contrast with “natural”, large-scale, overbank flood pulses. We compared the effects of a managed and a natural connection event on (i) the composition of the large-bodied fish community and (ii) the structure of an endangered catfish population of a large floodplain lake. The change in community composition following the managed connection was not greater than that exhibited between seasons or years during disconnection. By contrast, the change in fish community structure following the natural connection was much larger than that attributed to background, within- and between-year variability during disconnection. Catfish population structure only changed significantly following the natural flood. While the natural flood increased various population rates of native fishes, it also increased those of non-native carp, a pest species. To have a positive influence on native biodiversity, environmental flows may need to be delivered to floodplains in a way that simulates the properties of natural flood pulses. A challenge, however, will be managing river-floodplain connectivity to benefit native more than non-native species.

scholarly journals Understanding spatial and temporal patterns of human–elephant conflict in Assam, India

Oryx ◽  
2013 ◽  
Vol 49 (1) ◽  
pp. 140-149 ◽  
Author(s):  
Scott Wilson ◽  
Tammy E. Davies ◽  
Nandita Hazarika ◽  
Alexandra Zimmermann
Keyword(s):  
Large Scale ◽  
Spatial And Temporal Patterns ◽  
Forest Patches ◽  
Small Communities ◽  
Crop Density ◽  
Tea Plantations ◽  
A Priority ◽  
Study Sites ◽  
Conflict Mitigation ◽  
Refuge Areas

AbstractLarge-scale forest encroachment in Assam, India, has led to increasing levels of human–elephant conflict. Conflict mitigation is a priority for the survival of Asian elephants Elephas maximus throughout Asia. We analysed a 3-year dataset of elephant occurrence and related instances of human–elephant conflict, from two sites in Assam, and explored the relationships between the various effects of elephants on human communities and factors influencing the spatial and temporal occurrence of these effects (proximity to water, refuge areas and villages, and human and crop density). The landscapes at both study sites have been transformed by forest loss, with large areas converted to agriculture. Remaining forest patches, which are mostly small, disconnected and degraded, as well as tea plantations, provide refuge areas for elephants as they move through the region. We found that crop depredation and property damage caused by elephants showed well-defined seasonal trends. They also showed a clear diurnal pattern, mostly occurring between 18.00 and 22.00. Small communities within 700 m of a refuge were most affected. In the management of human–elephant conflict in Assam we need to consider the refuge patches used by elephants as they move through the region, the peripheries of which are likely to be conflict hotspots. Small villages on the edges of refuges should be a priority for conflict mitigation assistance, with strategies taking into account seasonal and diurnal variation in elephant behaviour, as well as the socio-economic and cultural composition of communities.

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