Bottom-up Effects on Tri-trophic Interactions: Plant Fertilization Enhances the Fitness of a Primary Parasitoid Mediated by Its Herbivore Host

2020 ◽  
Vol 113 (6) ◽  
pp. 2619-2626
Author(s):  
Apostolos Pekas ◽  
Felix L Wäckers
Keyword(s):  
Natural Enemies ◽  
Nitrogen Concentration ◽  
Mass Rearing ◽  
Reproductive Capacity ◽  
Biological Pest Control ◽  
Tobacco Plants ◽  
Primary And Secondary Metabolites ◽  
Food Quantity ◽  
Nitrogen Treatment ◽  
The Impact

Abstract Plants play a pivotal role in interactions involving herbivores and their natural enemies. Variation in plant primary and secondary metabolites not only affects herbivores but, directly and indirectly, also their natural enemies. Here, we used a commercial NPK fertilizer to test the impact of three fertilizer, namely 50, 100, and 200 ppm nitrogen, and one control (i.e., water) treatments, on the weight of the nymphs of the whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). Subsequently, the whitefly parasitoid Eretmocerus mundus Mercet (Hymenoptera: Aphelinidae) was reared on the different groups of whitefly nymphs and upon parasitoid emergence, the number of oocytes was determined as a measure of reproductive capacity. Trials were done on tomato and tobacco plants. The level of nitrogen concentration in tobacco leaves was directly correlated with the fertilizer applications, thus confirming the effect of our fertilizer treatments. Both in tomato and tobacco plants, healthy as well as parasitized whitefly nymphs, were heaviest in the 200 ppm nitrogen treatment. The highest number of oocytes per female parasitoid was recorded in the 200 ppm nitrogen treatment in tomato (31% more oocytes as compared with the control) and in the 100 and 200 ppm nitrogen treatments in tobacco (200% more oocytes). We suggest that the increase in oocytes was the result of the enhanced size (food quantity) and/or nutritional quality of the whitefly host. The practical implications of these results for the mass rearing of whitefly parasitoids and for biological pest control are discussed.

scholarly journals Assessment of Glyphosate Impact on the Agrofood Ecosystem

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 405
Author(s):  
Yaxin Sang ◽  
Juan-Carlos Mejuto ◽  
Jianbo Xiao ◽  
Jesus Simal-Gandara
Keyword(s):  
Risk Assessment ◽  
Food Production ◽  
Mitigation Strategies ◽  
Regulatory Control ◽  
Biological Pest Control ◽  
Effective Strategies ◽  
Nutrition Security ◽  
Production And Consumption ◽  
Food And Nutrition ◽  
The Impact

Agro-industries should adopt effective strategies to use agrochemicals such as glyphosate herbicides cautiously in order to protect public health. This entails careful testing and risk assessment of available choices, and also educating farmers and users with mitigation strategies in ecosystem protection and sustainable development. The key to success in this endeavour is using scientific research on biological pest control, organic farming and regulatory control, etc., for new developments in food production and safety, and for environmental protection. Education and research is of paramount importance for food and nutrition security in the shadow of climate change, and their consequences in food production and consumption safety and sustainability. This review, therefore, diagnoses on the use of glyphosate and the associated development of glyphosate-resistant weeds. It also deals with the risk assessment on human health of glyphosate formulations through environment and dietary exposures based on the impact of glyphosate and its metabolite AMPA—(aminomethyl)phosphonic acid—on water and food. All this to setup further conclusions and recommendations on the regulated use of glyphosate and how to mitigate the adverse effects.

scholarly journals Phytotoxicity of Silver Nanoparticles on Tobacco Plants: Evaluation of Coating Effects on Photosynthetic Performance and Chloroplast Ultrastructure

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 744
Author(s):  
Petra Peharec Štefanić ◽  
Karla Košpić ◽  
Daniel Mark Lyons ◽  
Lara Jurković ◽  
Biljana Balen ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Cetyltrimethylammonium Bromide ◽  
Photosynthetic Apparatus ◽  
Chloroplast Ultrastructure ◽  
Photosynthetic Performance ◽  
Pigment Content ◽  
Inhibitory Effects ◽  
Tobacco Plants ◽  
Agriculture And Food ◽  
The Impact

Silver nanoparticles (AgNPs) are the most exploited nanomaterial in agriculture and food production, and their release into the environment raises concern about their impact on plants. Since AgNPs are prone to biotransformation, various surface coatings are used to enhance their stability, which may modulate AgNP-imposed toxic effects. In this study, the impact of AgNPs stabilized with different coatings (citrate, polyvinylpyrrolidone (PVP), and cetyltrimethylammonium bromide (CTAB)) and AgNO3 on photosynthesis of tobacco plants as well as AgNP stability in exposure medium have been investigated. Obtained results revealed that AgNP-citrate induced the least effects on chlorophyll a fluorescence parameters and pigment content, which could be ascribed to their fast agglomeration in the exposure medium and consequently weak uptake. The impact of AgNP-PVP and AgNP-CTAB was more severe, inducing a deterioration of photosynthetic activity along with reduced pigment content and alterations in chloroplast ultrastructure, which could be correlated to their higher stability, elevated Ag accumulation, and surface charge. In conclusion, intrinsic properties of AgNP coatings affect their stability and bioavailability in the biological medium, thereby indirectly contributing changes in the photosynthetic apparatus. Moreover, AgNP treatments exhibited more severe inhibitory effects compared to AgNO3, which indicates that the impact on photosynthesis is dependent on the form of Ag.

Impact of age, size, and sex on adult black soldier fly [Hermetia illucens L. (Diptera: Stratiomyidae)] thermal preference

2021 ◽  
pp. 1-12
Author(s):  
N.F. Addeo ◽  
C. Li ◽  
T.W. Rusch ◽  
A.J. Dickerson ◽  
A.M. Tarone ◽  
...  
Keyword(s):  
Life History ◽  
Thermal Gradient ◽  
Life History Traits ◽  
Animal Feed ◽  
Mass Rearing ◽  
Thermal Preference ◽  
Black Soldier Fly ◽  
Hermetia Illucens ◽  
Surface Temperatures ◽  
The Impact

Population growth and rapid urbanisation have increased the global demand for animal feed and protein sources. Therefore, traditional animal feed production should be increased through the use of alternative nutrient sources. Insects as feed are beginning to fill this need. One such insect is the black soldier fly, Hermetia illucens L. (Diptera: Stratiomyidae). However, to more effectively mass produce the black soldier fly, a better understanding of its thermal biology is needed. Thus, the aim of this study was to evaluate the impact of age, size, and sex on adult black soldier fly thermal preference. The thermal preference of adult black soldier flies was determined by exposing flies to a thermal gradient with a range of surface temperatures and monitoring their positions over time. An aluminium plate was used to create a linear thermal gradient where surface temperatures ranged from ~15-60 °C. Flies were distinguished by age (1-d-post-emergence vs 7-d-post-emergence), size (large vs small) and sex (male vs female) to assess whether thermal preference differed by specific life-history traits. Thermal preference for 7-d-post-emergence adults was significantly lower (19.2 °C) than 1-d-post-emergence adults (28.7 °C), respectively. Similarly, small adults selected significantly cooler (21.1 °C) temperatures than large adults (26.9 °C). No significant differences in thermal preferences were found between sex, regardless of age or size. In fact, males and females had similar thermal preference of 23.8 and 24.2 °C, respectively. This study reveals that multiple life-history traits of adult black soldier fly affect their thermal preference, and thus should be taken into consideration by mass rearing facilities to optimize production.

scholarly journals Crop Diversification Affects Biological Pest Control

2013 ◽  
Vol 14 (3) ◽  
pp. 449 ◽  
Author(s):  
Dimitrije Marković
Keyword(s):  
Pest Control ◽  
Habitat Management ◽  
Crop Diversification ◽  
Agricultural Systems ◽  
Beneficial Arthropods ◽  
Habitat Manipulation ◽  
Biological Pest Control ◽  
Agricultural Ecosystems ◽  
The Impact

Crop monocultures encourage the multiplication and spread of pest insects on massive and uniform crop. Numerous studies have evaluated the impact of plant diversification on pests and beneficial arthropods population dynamics in agricultural ecosystems and provided some evidence that habitat manipulation techniques like intercropping can significantly influence pest control. This paper describes various potential options of habitat management and design that enhance ecological role of biodiversity in agroecosystems. The focus of this review is the application and mechanisms of biodiversity in agricultural systems to enhance pest management.

scholarly journals Reppoductive ability of ukrainian black and white dairy cows

2016 ◽  
Vol 18 (2) ◽  
Author(s):  
M. I. Kuziv ◽  
E. I. Fedorovych
Keyword(s):  
Milk Yield ◽  
Milk Fat ◽  
Reproductive Capacity ◽  
Dry Period ◽  
Black And White ◽  
Reproductive Ability ◽  
Service Period ◽  
Lactation Duration ◽  
The Impact ◽  
Period Duration

The major components of economically useful traits in cattle dairy productivity, which conducted the selection is milk productivity and reproductive ability of cows. Studies conducted on animals Ukrainian black and white dairy cattle in the «Milk River» farm in the Sokal and Brody offices breeding reproducers «Breeder» Lviv region and plant breeding «Yamnytsya» Ivano–Frankivsk region. Ukrainian black and white dairy breed in the western region of Ukraine is characterized by good reproductive ability. Depending on the husbandry and lactation duration, service period lasted within 87.4 – 121.5 day, intercalving period – within 364 – 402.6 day, dry period within – 47.3 – 72.9 day, the fertility index was 46.3 – 48.0, coefficient of reproductive ability – within 0.92–0.99,  output of calves per 100 cows – within 91.8 – 98.8. The duration of pregnancy in cows of different  farms and lactations were in range 277 – 283.5 day and meet the requirements of the physiological norm. It has been shown that the milk yield of cows depends on the parameters of reproductive capacity. The correlation between duration of service–period and intercalving period, and milk yield, milk fat in most cases was positive. Correlation dry period duration and parameters of milk yield changed from negative to positive. Depending on the husbandry, lactation and index the impact share of service–period duration on milk yield was 7.0 – 29.7, for intercalving period – 8.8 – 31.8, for dry period – 9.2 – 23.8% respectively.

scholarly journals Impactos do Programa de Aquisição de Alimentos (PAA) no Rendimento Escolar dos Municípios do Paraná

2019 ◽  
Vol 20 (4) ◽  
pp. 446-451
Author(s):  
Renata Cattelan ◽  
Lirane Elize Defante Ferreto
Keyword(s):  
School Performance ◽  
Dropout Rate ◽  
Food Shortage ◽  
Early Years ◽  
Pass Rate ◽  
Food Quantity ◽  
Politica Publica ◽  
Keywords Education ◽  
The Impact ◽  
Distortion Rate

No Brasil, ao longo das últimas décadas, algumas políticas públicas procuraram sanar os problemas da carência alimentar. Contudo, a insegurança alimentar tem fatores multidimensionais e impacta de maneiras variadas na vida da população, especialmente de crianças e adolescentes. O impacto da quantidade e qualidade insuficiente dos alimentos pode ser um fator de redução do rendimento escolar. O Programa de Aquisição de Alimentos (PAA) é uma política pública que visa a distribuição de alimentos de qualidade nas escolas, bem como em outros órgãos, e que objetiva gerar renda no campo ao mesmo tempo em que oferece qualidade nutricional. Partindo do problema da carência alimentar para crianças e adolescentes e como isso afeta a produtividade escolar, o objetivo desta pesquisa é avaliar o impacto do PAA no rendimento escolar de crianças e adolescentes que estudam em escolas que são beneficiárias do programa. A metodologia utilizada foi o teste de Mann-Whitney e as variáveis utilizadas foram o IDEB, a taxa de aprovação, a taxa de abandono escolar e a taxa de distorção idade/série para o ensino fundamental séries iniciais e finais. O recorte geográfico é o estado do Paraná, e temporal, os anos de 2013 e 2015. O principal resultado do estudo mostrou que a variável taxa de distorção idade/série dos anos iniciais do ensino fundamental, para o grupo formado pelos municípios afetados pelo PAA, obteve melhora estatisticamente significativa em relação a municípios que não participaram do programa. Palavras-chave: Educação. Segurança Alimentar e Nutricional. Teste de Mann-Whitney. AbstractIn Brazil, over the last decades, some public policies have tried to remedy the problems of food shortage. However, food insecurity has multidimensional factors and impacts in various ways on the lives of the population, especially children and teenagers. The impact of insufficient food quantity and quality may be a factor in reducing school performance. The Food Acquisition Program (FAP) is a public policy aimed at the distribution of quality food in schools as well as other agencies, and which aims to generate income in the countryside while providing nutritional quality. Starting from the problem of food shortage for children and teenagers, and how it affects school productivity, the objective of this research is to evaluate the impact of FAP on the school performance of children and adolescents who study in schools that benefit from the program. The methodology used was the Mann-Whitney test and the variables used were the IDEB, the pass rate, the dropout rate and the age / grade distortion rate for elementary and early grades. The geographical cut is the state of Paraná, and temporal, the years 2013 and 2015. The main result of the study showed that the variable age / grade distortion rate of the early years of elementary school, for the group formed by the municipalities affected by the FAP, obtained statistically significant improvement compared to counties that did not participate in the program. Keywords: Education. Food Safety and Nutrition. Test of Mann-Whitney. 

scholarly journals Cytokinin Dynamics during the Response to Nitrogen in Two Contrasting Plectranthus Genotypes

2016 ◽  
Vol 141 (3) ◽  
pp. 264-274 ◽  
Author(s):  
Ellen T. Paparozzi ◽  
Jazbaat K. Chahal ◽  
Petre Dobrev ◽  
Elizabeth A. Claassen ◽  
Walter W. Stroup ◽  
...  
Keyword(s):  
Chlorophyll Content ◽  
Nitrogen Limitation ◽  
Nitrogen Deficiency ◽  
Nitrogen Response ◽  
Nitrogen Resupply ◽  
Phenotypic Variations ◽  
Nitrogen Treatment ◽  
Specific Regulation ◽  
The Impact ◽  
Hydrolysis Of

Nitrogen response was compared in two Plectranthus species, Plectranthus parviflorus and Plectranthus ambiguus, which differ substantially in their phenotypic reaction to nitrogen limitation. The leaves of the former species gradually yellow during the nitrogen stress but are retained on the plant. This species copes with nitrogen deficiency also by gradual hydrolysis of starch grains. The latter species, P. ambiguus, responds by abscission of lower leaves. As plant hormones cytokinins are involved in nitrogen response as well as in regulation of the chlorophyll content, their dynamics were followed to explore the fast responses as well as the impact of nitrogen treatment. Both plant species responded to nitrogen deficiency/supplementation in similar ways, by downregulation and upregulation, respectively, of active cytokinins. However, the different phenotypic reactions imposed by nitrogen limitation were associated with specific regulation of cytokinin pool accompanying the stress response by the two species. The increase of the active cytokinins on nitrogen resupply was faster and stronger in the regreening species, P. parviflorus than in P. ambiguus. However, the P. ambiguus plants maintained higher basal levels of all cytokinin metabolites as well as chlorophyll content when compared with P. parviflorus. Nitrogen deficiency was associated in this species with accumulation of cis-zeatin-type cytokinins, which preceded abscission of lower and later on of middle leaves. The achieved results indicate that phenotypic variations in the response to nitrogen deficiency/supplementation are associated with significant quantitative and qualitative differences in the cytokinin pool.

scholarly journals INFLUENCE OF DIFFERENT VERSIONS ARTIFICIAL INSEMINATION OF GILTS OF THEIR TRAITS OF THE REPRODUCTIVE ABILITY CONSOLIDATION

2018 ◽  
Vol 56 ◽  
pp. 130-135
Author(s):  
M. V. Tserenyuk ◽  
O. M. Tserenyuk
Keyword(s):  
Artificial Insemination ◽  
Reproductive Capacity ◽  
Mean Square ◽  
Mean Square Deviation ◽  
Reproductive Ability ◽  
Coefficient Of Variability ◽  
Current Instruction ◽  
The Mean ◽  
The Difference ◽  
The Impact

In addition to assessing the absolute performance of animals, the impact of certain technological approaches, breeding influence and other external organized factors on the consolidation of pigs groups on certain grounds should be evaluated. Breeding consolidation is a desirable breeding process that is realized through more motivated consolidation of intra-breeding structural units for maintaining a significant level of intergroup differentiation and variability. If the issue relates to the rearing young animals that are introduced into the herd, this is the most urgent issue that needs to be monitored. The purpose of the research is to determine the consociality of the main signs of reproductive ability of the gilts, which are checked at different rates of artificial insemination of sows of the main herd. The research was carried out at the Shubs`ke farm in the Bogoduhivsky District of Kharkiv Oblast at the pig farm for the pure breeding of the Welsh breed pigs (breeding reproductive status from 2014). In order to evaluate the optimal multiplicity (from single to triple), a gilts with a total of 30 heads was selected. The main indicators of reproductive ability of gilts (multiplicity, weight of nest at birth and excommunication and keeping piglets before weaning on day 28) were evaluated. Recalculation on the weight of the litter at weaning at the weight of the nest at extermination in 60 days was carried out in accordance with the current instruction on the boning of pigs. The results of researches were worked out according to traditional methods by the method of variation statistics. Consolidation of individual indicators of reproductive capacity of gilts was calculated to the total number of evaluated animals. In the previous stage of the research, it was found that the use of multiple insemination of gilts compared to single insemination is positively reflected at the level of their reproductive ability. A decrease in the percentage of non-productive inseminants in animal groups has been established. Triple insemination of gilts allows for 1.14 piglets to be obtained more compared to single insemination of the same pigs (p < 0.01). Also, for three times insemination of gilts, in comparison with single insemination, larger nest for weaning were obtained (by 14.24 kg, converted to 60th day p < 0.01). At the same time, the reduction in the keeping of piglets to weaning for increase frequency of insemination of gilts. According to the multiplicity of gilts, the most consolidated level of symptoms per group was obtained for single insemination. Increasing the multiplicity of insemination negatively affected the consolidation of the multiplicity of the piglets (as for determining the coefficients of phenotypic consolidation due to the mean square deviation, so, and for determining the coefficient of variability). The least consolidated in terms of multiplicity were uterus for double insemination. It should also be noted that there is little difference, in general, on the indicators of the theonotypical consolidation of the multiplicity of piglets between different groups of animals. So this difference between the most contrasting groups was 0.447 points for determining the coefficients due to the mean square deviation and 0.397 points for the determination due to the coefficient of variability, respectively. By weight of the same litters at birth, the most consolidated group was gilts, which was inseminated twice. The least consolidated are trimmed three times, respectively. The difference as a whole, according to the indicators of the theonotype consolidation of the mass of the litter’s piglets at birth, between different groups of pigs was even smaller. The difference between the most contrasting groups was 0.270 points for determining the coefficients due to the mean square deviation and 0.260 points for the determination due to the coefficient of variability, respectively. On the basis of the mass of the litter at weaning, the most consolidated level of symptoms was obtained in the group of gilts for triple insemination. The least consolidated group, respectively, was gilts for single insemination. At the same time, on the basis of the weight of the litter at weaning, the slightest differences were obtained after the consolidation of the signs between different groups of pigs. The difference between the most contrasting groups was 0.173 points for determining the coefficients due to the mean square deviation and 0.248 points for the determination due to the coefficient of variation, respectively. At different rates of insemination of gilts, there are no significant differences between the groups between the groups in terms of the consolidation of signs of reproductive ability. Also, there was no clear effect on increasing the multiplicity of insemination of gilts to the consolidation of their signs of reproductive qualities.

Optical Characterization of VLS+CVD Grown 3C-SiC Films by Non-Linear and Photoluminescence Techniques

2010 ◽  
Vol 645-648 ◽  
pp. 443-446 ◽  
Author(s):  
Georgios Manolis ◽  
Georgios Zoulis ◽  
Sandrine Juillaguet ◽  
Jean Lorenzzi ◽  
Gabriel Ferro ◽  
...  
Keyword(s):  
Nitrogen Concentration ◽  
Free Carrier ◽  
Free Carrier Absorption ◽  
Free Carrier Density ◽  
Temperature Dependences ◽  
Carrier Absorption ◽  
Data Investigation ◽  
The Impact ◽  
Sic Films

Thin 3C-SiC(111) epilayers grown on 6H-SiC(0001) substrate by VLS and CVD procedures were studied by low temperature photoluminescence (LTPL) and nonlinear optical techniques at room and low temperatures. Free carrier density ((0.3-7)×1017 cm-3) and nitrogen concentration (4×1016 cm-3) in the layers were determined from Raman and LTPL data. Investigation of non-equilibrium carrier dynamics by using transient grating and free carrier absorption techniques provided an ambipolar diffusion coefficient Da (~2.5 cm2/s) and carrier lifetime τR (2-4 ns) values at room temperature. The temperature dependences of Da and τR in 40-300 K range revealed the scattering processes in high density plasma as well the impact of defects.

scholarly journals Dynamics and Management of Rising Outbreak Spruce Budworm Populations

Forests ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 748 ◽  
Author(s):  
Jacques Régnière ◽  
Barry Cooke ◽  
Ariane Béchard ◽  
Alain Dupont ◽  
Pierre Therrien
Keyword(s):  
Population Growth ◽  
Density Dependence ◽  
Natural Enemies ◽  
Choristoneura Fumiferana ◽  
Regional Scale ◽  
Adult Emergence ◽  
Spruce Budworm ◽  
Migration Activity ◽  
Larval Stages ◽  
The Impact

Management of spruce budworm, Choristoneura fumiferana (Clem.), outbreak spread requires understanding the demographic processes occurring in low, but rising populations. For the first time, detailed observations were made in the early stages of outbreak development. We sampled populations over a three-year period in both treated and untreated populations in the Lower St-Lawrence region of Quebec, Canada, and measured the density-dependence of survival and population growth rates, and the impact of natural enemies and insecticides. Insecticides tested were Bacillus thuringiensis (Berliner 1915) and tebufenozide. We recorded strong density-dependence of survival between early larval stages and adult emergence, explained largely by the variation of natural enemy impacts and overcrowding. We also observed inverse density-dependence of apparent fecundity: net immigration into lower-density populations and net emigration from the higher, linked to a threshold of ~25% defoliation. Because of high migration rates, none of the 2013 treatments reduced egg populations at the end of summer. However lower migration activity in 2014 allowed population growth to be reduced in treated plots. This evidence lends support to the conclusion that, for a budworm population to increase to outbreak density, it must be elevated via external perturbations, such as immigration, above a threshold density of ~4 larvae per branch tip (L4). Once a population has increased beyond this threshold, it can continue growing and itself become a source of further spread by moth migration. These findings imply that populations can be brought down by insecticide applications to a density where mortality from natural enemies can keep the reduced population in check, barring subsequent immigration. While we recognize that other factors may occasionally cause a population to exceed the Allee threshold and reach outbreak level, the preponderance of immigration implies that if all potential sources of significant numbers of moths are reduced on a regional scale by insecticide applications, a widespread outbreak can be prevented, stopped or slowed down by reducing the supply of migrating moths.

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