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1.
Polymers (Basel) ; 15(15)2023 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-37571150

RESUMO

The light weight, electrical conductivity, environmental friendliness, and high mechanical properties of graphene/PEKK composites make them popular in biomedical, electronic component and aerospace fields. However, the compaction density and carbonization of the specimen influence the microstructure and conductivity of the graphene/PEKK composite prepared by in situ polymerization, so electromagnetic-assisted molding was used to manufacture products to avoid carbonization and enhance the compaction density. The effects of different discharge voltages on the microstructure of the formed graphene/PEKK specimens were compared. Increasing the discharge voltage will lead to a closer distribution of flake graphene in the matrix to improve the compaction density, mechanical performance and conductivity. At the same time, the numerical analysis model was validated by comparison with the compaction density of the experimental results. Based on this research, the stress/strain distribution on the specimen was obtained with increasing discharge voltages.

2.
J Phys Chem A ; 127(36): 7510-7517, 2023 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-37647565

RESUMO

The Stone-Wales defect is a well-known and significant defective structure in carbon materials, impacting their mechanical, chemical, and electronic properties. Recently, a novel metal-carbon nanomaterial named Volleyballene was discovered, characterized by a C-C bond bridging two carbon pentagons. Using first-principles calculations, a stable Stone-Wales-defective counterpart of Volleyballene, exhibiting Th symmetry, has been proposed by rotating the C-C bond by 90°. Although its binding energy per atom is slightly higher than that of Volleyballene (ΔEb = 0.009 eV/atom), implying marginally lower structural stability, it can maintain its bond structure until the effective temperature reaches about 1500 K, indicating greater thermodynamic stability. Additionally, its highest vibration frequency is 1346.2 cm-1, indicating a strong chemical bond strength. A theoretical analysis of the Sc20C60 + Sc20C60 binary systems highlights that the stable building block may be applied in potential nanoassemblies.

3.
J Acupunct Meridian Stud ; 16(2): 70-78, 2023 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-37076182

RESUMO

Background: Adhesive capsulitis is a progressive, idiopathic disorder that significantly impacts individuals̓ daily lives and increases their medical burden. Pharmacopuncture therapy, which combines acupuncture techniques with herbal medicine, involves injecting herbal extracts into specific acupoints. This study aims to determine the effectiveness and safety of pharmacopuncture therapy in comparison to physiotherapy (PT) for treating adhesive capsulitis. Methods: This research protocol outlines a two-arm, parallel, multi-center, pragmatic randomized controlled trial. Fifty participants will be randomly allocated to either the pharmacopuncture therapy or PT group, and they will receive 12 sessions of their respective therapies over a 6-week period. The primary outcome measure is the numeric rating scale for shoulder pain. Secondary outcomes include the visual analog scale score for shoulder pain, Shoulder Pain and Disability Index, Patients̓ Global Impression of Change score, Short Form-12 Health Survey Version 2 score, and EuroQol-5 Dimension. Statistical analysis will be conducted based on the intention-to-treat principle. Discussion: This trial may offer high-quality and reliable clinical evidence for evaluating the effectiveness and safety of pharmacopuncture therapy compared to PT in the treatment of adhesive capsulitis. Furthermore, this study will serve as a valuable guideline for practitioners when making clinical decisions and managing adhesive capsulitis.


Assuntos
Terapia por Acupuntura , Acupuntura , Bursite , Humanos , Terapia por Acupuntura/métodos , Bursite/terapia , Estudos Multicêntricos como Assunto , Modalidades de Fisioterapia , Projetos de Pesquisa , Dor de Ombro/terapia , Resultado do Tratamento , Ensaios Clínicos Pragmáticos como Assunto
4.
Plants (Basel) ; 11(20)2022 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-36297778

RESUMO

Crop resistance and biological control are both considered efficient and environmentally friendly methods of sustainable pest control. In this study, we aimed at investigating the direct influence of four wheat lines with varying resistance level on the life-history traits of the greenbug, Schizaphis graminum, and the mediational effect on the functional response of a predatory ladybird, Propylaea japonica, under laboratory conditions. Results showed that the aphid fitness was the lowest for aphids that had been feeding on wheat line '98-10-19' for one year. These aphids had the longest development time, and least adult mass, minimal mean relative growth rate, and lowest reproductive fitness. In contrast, the aphids that fed on wheat line '98-10-30' were the fittest, with the shortest development time and highest levels of reproductive fitness. The predatory activities of the ladybeetle, especially the adult male significantly decreased following the consumption of aphids belonging to the '98-10-19'-acclimated population. However, there were no significant differences in predatory efficiency (net attack frequency) among the four aphid acclimated populations. Our results showed that the wheat line '98-10-19' has a relative higher resistance to S. graminum than the other three wheat lines, which could further decrease the amount of prey available for consumption. However, the ecological effect of the resistance of '98-10-19' to S. graminum posed no negative influence on the biocontrol potential of P. japonica to these aphids, as their predatory efficiency increases at the fourth instar larvae phase.

5.
Medicine (Baltimore) ; 101(51): e31531, 2022 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-36595747

RESUMO

BACKGROUND: This systematic review aimed to assess the effectiveness and safety of acupoint catgut embedding (ACE), which is widely used in simple obese patients. METHODS: Nine electronic databases and 2 trial registries were searched from inception to September 2021 without language limitations. All randomized controlled trials involving ACE therapies for simple obesity were included. Assessment of Cochrane's risk of bias and meta-analysis, as well as GRADE evaluation, were also performed. RESULTS: A total of 73 randomized clinical trials involving 5872 participants were included. The overall risk of bias was high or unclear. ACE showed higher efficacy in total effective rate, body mass index, and body weight than manual acupuncture. In addition, ACE is more beneficial in total effective rate than electroacupuncture (EA). Moreover, combination therapy of ACE with EA is more effective in total body mass index and body weight than EA alone. CONCLUSIONS: Despite some potential improvement, the evidence regarding the effectiveness and efficacy of ACE for simple obesity is inconclusive due to the poor quality of evidence. Further well-designed randomized controlled trials are needed to confirm the effectiveness of ACE for simple obesity.


Assuntos
Terapia por Acupuntura , Obesidade Mórbida , Humanos , Pontos de Acupuntura , Categute , Revisões Sistemáticas como Assunto , Metanálise como Assunto , Terapia por Acupuntura/métodos , Obesidade/terapia , Ensaios Clínicos Controlados Aleatórios como Assunto
6.
Phys Chem Chem Phys ; 23(45): 25485-25489, 2021 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-34757349

RESUMO

In this communication, we investigate the lattice dynamics of twisted graphene nanoribbons using the density-functional tight-binding method based on screw symmetry. The results show that the decrease in phonon group velocity induced by twisting reduces the lattice thermal conductivity. Our findings provide inspiration for the design of graphene-based phononic devices tailored by inhomogeneous strain.

7.
J Insect Sci ; 21(5)2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34655291

RESUMO

Crop resistance plays a role in preventing aphid damage, benefiting food production industries, but its effects are limited due to aphid adaptation and phenotypic plasticity. Therefore, furthering understanding of aphid-crop interactions will improve our ability to protect crops from aphids. To determine how aphids adapt to resistant varieties of wheat, Triticum aestivum L. over time, we performed a laboratory experiment to assess the multi-generational effects of three wheat varieties, Batis, Ww2730, and Xiaoyan22, with different resistance levels on the fitness of Sitobion avenae (Fab.) (Hemiptera: Aphididae). The results showed that Ww2730 and Xiaoyan22 were more resistant than Batis to S. avenae, regardless of whether the aphids were newly introduced or had been acclimated before being introduced to the three wheat varieties. However, the effect of resistance on aphid life-history traits was time dependent. Aphid weigh gain increased and they development faster of the acclimated generation compared to the newly introduced generation on all three varieties. And the fecundity on the three varieties and net reproduction rates on Batis and Xiaoyan22 significantly decreased. Aphid fitness in terms of individual life-history parameters improved, whereas aphid fitness in terms of reproductive decreased, and a convergence effect, the difference gaps and standard errors of all life-history traits among the three acclimated populations had narrowed and were less than those in the three first-generation populations, was observed during the 3-mo experimental period. We suggested that S. avenae could rapidly respond to wheat resistance through life-history plasticity.


Assuntos
Afídeos , Controle de Insetos , Triticum , Animais , Afídeos/crescimento & desenvolvimento , Afídeos/fisiologia , Produtos Agrícolas , Fertilidade , Características de História de Vida , Defesa das Plantas contra Herbivoria , Folhas de Planta , Reprodução
8.
J Phys Chem A ; 124(22): 4440-4444, 2020 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-32374997

RESUMO

A chiral molecule with octahedral symmetry, Re6C32, has been identified using first-principles calculations. It is a hollow cage with the shape of Catalan pentagonal icositetrahedron. The calculated vibrational frequencies are in the range of 83.0-1341.2 cm-1, which indicate the stability of the Re6C32 molecule. Molecular dynamics simulations show that the topological structure of the Re6C32 molecule is well maintained up to 1500 K. The electronic structural analysis shows that there are significant p-d orbital hybridizations near the Fermi level. Moreover, the Re6C32 molecule is magnetic with spin magnetic moment of 12 µB. This magnetic carbon-based hollow Re6C32 cage may become a candidate for single-molecule devices.

9.
J Econ Entomol ; 113(1): 461-470, 2020 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-32034919

RESUMO

Hormone-dependent responses in host plants induced by herbivore infestation have species-specific effects. This study focused on determining the relative expression profiles of the genes associated with hormone-dependent pathways in two near-isogenic wheat lines when attacked by cereal aphids. Infestation with Rhopalosiphum padi Linnaeus (Hemiptera: Aphididae) and/or Sitobion avenae Fabricius (Hemiptera: Aphididae) significantly upregulated the expression of marker genes related to the salicylic acid (SA)- and jasmonic acid (JA)-dependent pathways in the tested lines. In the resistant line 35-E4, previous infestation with R. padi significantly increased the relative expression of plant pathogenesis-related protein 1 at all sampling times but did not have a significant effect on the expression of the phenylalanine ammonia-lyase (PAL) gene. In addition, the expression levels of the lipoxygenase (LOX) and allene oxide synthase (AOS) genes immediately increased after the aphid attack. In susceptible line 35-A20, infestation with either R. padi or S. avenae led to significantly increased expression levels of the AOS and PAL genes. Moreover, sequential aphid infestation induced higher expression of AOS compared with a single-species aphid infestation, whereas the expression of the PAL gene was antagonistically affected by sequential aphid infestation. Overall, these results showed that aphid infestation induced SA- and JA-dependent responses in host plants. However, the expression profiles of these genes in resistant and susceptible host lines were significantly different.


Assuntos
Afídeos , Animais , Herbivoria , Especificidade da Espécie , Triticum
10.
RSC Adv ; 10(14): 8303-8308, 2020 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-35497825

RESUMO

A stable core-shell volleyball-like structure of B12@Li20Al12 has been proposed using first-principles calculations. This structure with T h symmetry is constructed with a core structure of I h-B12 and a volleyball-like shell of Li20Al12. Frequency analysis and molecular dynamics simulations demonstrate the exceptional stability of B12@Li20Al12. The chemical bonding analysis for B12@Li20Al12 is also conducted to confirm its stability and 46 multi-center two-electron σ bonds are observed, which are widely distributed throughout the core-shell structure. For the hydrogen storage capacity of the B12@Li20Al12, our calculated results indicate that about 58 H2 molecules can be absorbed at most, leading to a gravimetric density of 16.4 wt%. The exceptionally stable core-shell volleyball-like B12@Li20Al12 combined with its high hydrogen storage capacity indicates that it can be one of the outstanding hydrogen storage materials of the future.

11.
Sci Rep ; 8(1): 7344, 2018 05 09.
Artigo em Inglês | MEDLINE | ID: mdl-29743686

RESUMO

The maternal effects of the English grain aphid, Sitobion avenae on offspring phenotypes and performance on wheat varieties with different resistance traits were examined. We found that both conditioning wheat varieties(the host plant for over 3 months) and transition wheat varieties affected the biological parameters of aphid offspring after they were transferred between wheat varieties with different resistance traits. The conditioning varieties affected weight gain, development time (DT), and the intrinsic rate of natural increase (rm), whereas transition varieties affected the fecundity, rm, net reproductive rate, and fitness index. The conditioning and transition wheat varieties had significant interaction effects on the aphid offspring's DT, mean relative growth rate, and fecundity. Our results showed that there was obvious maternal effects on offspring when S. avenae transferred bwteen wheat varieties with different resistance level, and the resistance traits of wheat varieties could induce an interaction between the conditioning and transition wheat varieties to influence the growth, development, reproduction, and even population dynamics of S. avenae. The conditioning varieties affected life-history traits related to individual growth and development to a greater extent, whereas transition varieties affected fecundity and population parameters more.


Assuntos
Afídeos/genética , Herança Materna/genética , Animais , Afídeos/fisiologia , Fertilidade , Fenótipo , Reprodução , Triticum/genética
12.
Sci Rep ; 8(1): 4167, 2018 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-29520030

RESUMO

A stable T h -symmetry Ti12C68 cage was systemically investigated using density functional theory. The structure of Ti12C68 is a hollow cage with twelve TiC13 subunit of three pentagons and one hexagon. The calculated frequencies are in the range 95.1 cm-1-1423.9 cm-1. There are no imaginary frequencies, showing its kinetic stability. Ab initio molecular dynamics simulations demonstrate that the topological structure of cage-like Ti12C68 cluster was well maintained when the effective temperature is up to 1139 K. The natural bond orbitals analysis shows that the d orbit of Ti atoms form four σ bonds with the neighboring four carbon atoms in each TiC13 subunit playing an important role in the cluster stability. The molecular frontier orbitals analysis indicates that Ti12C68 cage has a narrow HOMO-LUMO gap with metal-like property. It would be expected to enrich the species of hollow metal carbide clusters.

13.
Can J Microbiol ; 63(11): 921-927, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28926717

RESUMO

Fusarium graminearum is a plant pathogen that can cause the devastating cereal grain disease fusarium head blight in temperate regions of the world. Previous studies have shown that F. graminearum can synthetize indole-3-acetic acid (auxin) using l-tryptophan (L-TRP)-dependent pathways. In the present study, we have taken a broader approach to examine the metabolism of L-TRP in F. graminearum liquid culture. Our results showed that F. graminearum was able to transiently produce the indole tryptophol when supplied with L-TRP. Comparative gene expression profiling between L-TRP-treated and control cultures showed that L-TRP treatment induced the upregulation of a series of genes with predicted function in the metabolism of L-TRP via anthranilic acid and catechol towards the tricarboxylic acid cycle. It is proposed that this metabolic activity provides extra energy for 15-acetyldeoxynivalenol production, as observed in our experiments. This is the first report of the use of L-TRP to increase energy resources in a Fusarium species.


Assuntos
Fusarium/metabolismo , Redes e Vias Metabólicas , Triptofano/metabolismo , Grão Comestível/metabolismo , Perfilação da Expressão Gênica , Ácidos Indolacéticos/metabolismo , Indóis , Análise em Microsséries , Tricotecenos , Triticum/genética
14.
J Econ Entomol ; 109(6): 2418-2423, 2016 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-27780837

RESUMO

Exposing seeds to a high-voltage electrostatic field (HVEF) may influence the performance of herbivores and improve the germination rate by inducing biological and physiological changes in plants. In the current study, an age-stage, two-sex life table was established to evaluate the effects from directly exposing seeds to HVEFs on the performance of apterous Sitobion avenae (Fabricius) reared on winter wheat. We treated the wheat seeds by exposing them to an HVEF for 20 min at three intensities: 2, 4, or 6 KV/cm. Controls received no treatment (0 KV/cm). The results indicated that the parameters of the net reproductive rate (R0), the intrinsic rate of increase (r), and the mean generation span (T) of S. avenae were significantly reduced by HVEFs through multiple generations. In addition, the age-specific survival rate (lx) and comparison with the results of a Weibull equation analysis suggested that S. avenae had the shortest life span when seeds were exposed to an HVEF at 4 KV/cm. Overall, these findings indicated that direct exposure of wheat seeds to an HVEF at 4 KV/cm could adversely affect the performance of S. avenae.


Assuntos
Afídeos/fisiologia , Campos Eletromagnéticos , Herbivoria , Triticum/fisiologia , Animais , Afídeos/crescimento & desenvolvimento , Feminino , Longevidade , Masculino , Ninfa/crescimento & desenvolvimento , Ninfa/fisiologia , Dinâmica Populacional , Sementes/fisiologia
15.
Fungal Biol ; 120(9): 1135-45, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27567719

RESUMO

Fusarium graminearum is a devastating pathogenic fungus causing fusarium head blight (FHB) of wheat. This fungus can produce indole-3-acetic acid (IAA) and a very large amount of IAA accumulates in wheat head tissues during the first few days of infection by F. graminearum. Using liquid culture conditions, we have determined that F. graminearum can use tryptamine (TAM) and indole-3-acetonitrile (IAN) as biosynthetic intermediates to produce IAA. It is the first time that F. graminearum is shown to use the l-tryptophan-dependent TAM and IAN pathways rather than the indole-3-acetamide or indole-3-pyruvic acid pathways to produce IAA. Our experiments also showed that exogenous IAA was metabolized by F. graminearum. Exogenous IAA, TAM, and IAN inhibited mycelial growth; IAA and IAN also affected the hyphae branching pattern and delayed macroconidium germination. IAA and TAM had a small positive effect on the production of the mycotoxin 15-ADON while IAN inhibited its production. Our results showed that IAA and biosynthetic intermediates had a significant effect on F. graminearum physiology and suggested a new area of exploration for fungicidal compounds.


Assuntos
Vias Biossintéticas/genética , Fusarium/genética , Fusarium/metabolismo , Ácidos Indolacéticos/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Fusarium/efeitos dos fármacos , Fusarium/crescimento & desenvolvimento , Indóis/metabolismo , Micélio/efeitos dos fármacos , Micélio/crescimento & desenvolvimento , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/crescimento & desenvolvimento , Tricotecenos/metabolismo , Triticum/microbiologia , Triptaminas/metabolismo , Triptofano/metabolismo
16.
J Phys Chem A ; 120(31): 6303-8, 2016 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-27447846

RESUMO

A stable hollow copper silicide cage with Ih symmetry, Cu20Si12, constituted of a copper dodecahedron and a silicon icosahedron, was investigated using density functional theory. Molecular dynamics simulations show that Cu20Si12 retains its geometric topology up to an effective temperature of about 962 K. The molecule has a HOMO-LUMO gap of 1.099 eV, indicating its relatively high chemical stability. These frontier molecular orbitals show clear characteristics of hybridization between Si 3p and Cu 3d electrons. This proposed structure helps to extend the range of high-symmetry molecular polyhedral species. The hollow space within Cu20Si12 can be used to accommodate other atoms or molecules and emphasizes the benefit of studying endohedral fullerenes.

17.
PLoS One ; 11(6): e0156158, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27249206

RESUMO

The English grain aphid, Sitobion avenae, is a major pest species of wheat crops; however, certain varieties may have stronger resistance to infestation than others. Here, we investigated 3 classical resistance mechanisms (antixenosis, antibiosis, and tolerance) by 14 wheat varieties/lines to S. avenae under laboratory and field conditions. Under laboratory conditions, alatae given the choice between 2 wheat varieties, strongly discriminated against certain varieties. Specifically, the 'Amigo' variety had the lowest palatability to S. avenae alatae of all varieties. 'Tm' (Triticum monococcum), 'Astron,' 'Xanthus,' 'Ww2730,' and 'Batis' varieties also had lower palatability than other varieties. Thus, these accessions may use antibiosis as the resistant mechanism. In contrast, under field conditions, there were no significant differences in the number of alatae detected on the 14 wheat varieties. One synthetic line (98-10-30, a cross between of Triticum aestivum (var. Chris) and Triticum turgidum (var. durum) hybridization) had low aphid numbers but high yield loss, indicating that it has high antibiosis, but poor tolerance. In comparison, 'Amigo,' 'Xiaoyan22,' and some '186Tm' samples had high aphid numbers but low yield loss rates, indicating they have low antibiosis, but good tolerance. Aphid population size and wheat yield loss rates greatly varied in different fields and years for '98-10-35,' 'Xiaoyan22,' 'Tp,' 'Tam200,' 'PI high,' and other '186Tm' samples, which were hybrid offspring of T. aestivum and wheat related species. Thus, these germplasm should be considered for use in future studies. Overall, S. avenae is best adapted to 'Xinong1376,' because it was the most palatable variety, with the greatest yield loss rates of all 14 wheat varieties. However, individual varieties/lines influenced aphid populations differently in different years. Therefore, we strongly recommend a combination of laboratory and long-term field experiments in targeted planting regions to identify varieties/lines that consistently show high resistance to S. avenae infestation.


Assuntos
Afídeos/fisiologia , Triticum/parasitologia , Animais
18.
Sci Rep ; 6: 24500, 2016 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-27076264

RESUMO

A stable hollow Li20B60 cage with D2 symmetry has been identified using first-principles density functional theory studies. The results of vibrational frequency analysis and molecular dynamics simulations demonstrate that this Li20B60 cage is exceptionally stable. The feasibility of functionalizing Li20B60 cage for hydrogen storage was explored theoretically. Our calculated results show that the Li20B60 molecule can adsorb a maximum of 28 hydrogen molecules. With a hydrogen uptake of 8.190 wt% and an average binding energy of 0.336 eV/H2, Li20B60 is a remarkable high-capacity storage medium.

19.
Electromagn Biol Med ; 35(1): 1-7, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-25188418

RESUMO

Insects show a variety of responses to electric fields and most of them are associated with immediate effects. To investigate the long-term effects of static electric field on the wheat aphid Sitbion avenae, the insert was exposed to 4 min of a static electric field at intensities of 0, 2, 4, or 6 kV/cm. Development effects over 30 consecutive generations of the insect were studied. The results showed that the electric field could exert adverse effects on the developmental duration and total longevity of S. avenae nymphs regardless of exposure intensities or generations. The effects appeared to be more intense and fluctuated at higher electric field intensities and more insect generations. The most favorable exposure for development was 6 kV/cm for 4 min while the most detrimental electric fields were 2 kV/cm for 4 min and 4 kV/cm for 4 min. Among the treatments, the first instar duration was significantly prolonged while the adult longevities were significantly shortened in the sixth generation. The intrinsic rate of increase and net reproductive rate in the sixth generation were also the lowest among the 30 consecutive generations studied. Based on the results, the adverse effects of electric fields on insects may be used in the bio-control of pest insects in terms of pest management.


Assuntos
Afídeos/crescimento & desenvolvimento , Eletricidade , Controle de Insetos , Triticum , Análise de Variância , Animais , Afídeos/fisiologia , Longevidade , Ninfa/crescimento & desenvolvimento , Ninfa/fisiologia , Reprodução , Eletricidade Estática , Fatores de Tempo
20.
Sci Rep ; 5: 18549, 2015 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-26680508

RESUMO

The fecundity advantage hypothesis suggests that females with a large body size produce more offspring than smaller females. We tested this hypothesis by exploring the correlations between life-history traits of three aphid species feeding on ten wheat accessions at three levels of analysis with respect to the host plant: overall, inter-accession, and intra-accession. We found that fecundity was significantly correlated with mean relative growth rate (MRGR), weight gain, and development time, and that the faster aphid develops the greater body and fecundity, depending on aphid species, wheat accession, and analyses level. Larger aphids of all three species produced more offspring overall; this held true for Sitobion avenae and Schizaphis graminum at the inter-accession level, and for S. avenae, Rhopalosiphum padi, and S. graminum for three, five, and eight accessions respectively at the intra-accession level. Only one correlation, between intrinsic rates of natural increase (rm) and MRGR, was significant for all aphid species at all three analysis levels. A more accurate statement of the fecundity advantage hypothesis is that cereal aphids with greater MRGR generally maintain higher rm on wheat. Our results also provide a method for exploring relationships between individual life-history traits and population dynamics for insects on host plants.


Assuntos
Afídeos/crescimento & desenvolvimento , Fertilidade/fisiologia , Triticum/metabolismo , Animais , Ingestão de Alimentos , Feminino
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