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To accelerate the convergence rate of high-dimensional optimization problems, inspired by the cooperative hunting process of spider colonies named Anelosimus eximius, a new A. eximius colony algorithm (AECA) was proposed to solve combinatorial optimization problems. In the AECA, a certain direction component of the problem solution is represented as a certain direction in which a spider travels, so that a high-dimensional optimization problem can be transformed into multiple low-dimensional optimization problems. The AECA includes two intelligent behaviors: the random walk of spiders and the summoning of the initiator. The random walk of spiders ensures the diversity of spider colonies, whereas the summoning of the initiator can accelerate the convergence rate. We theoretically proved that the AECA is globally convergent. The inversion method of asteroid spectrum reflectance template can be used to solve the problem that the measured planetary spectrum is affected by the asteroid absorption effect and improves the accuracy of celestial Doppler difference velocimetry, which uses celestial spectrum to provide the information of velocity measurement for navigation. The essence of this method is the optimal combination problem of intrinsic mode functions (IMFs). We applied the AECA to the inversion of the planetary spectrum reflectance template. Experimental results show that, compared with genetic algorithms (GAs), the AECA can obtain the optimal combination of spectrum reflectance templates faster. In addition, to verify the universality of the AECA, for the classical knapsack problem, the AECA has a better optimization effect, faster convergence rate, and higher stability than other swarm intelligence algorithms such as GA, discrete particle swarm optimization, and the quantum genetic algorithm. [ABSTRACT FROM AUTHOR]

Pulsar timing arrays (PTAs) are effective in detecting low-frequency gravitational waves (GWs), especially in circular binary systems of supermassive black holes. To evaluate the effectiveness and accuracy of PTAs in searching for GW parameter estimation, we use the Cramer-Rao lower bound to estimate the parameters of the Virgo source under various search conditions, including both evolving and non-evolving scenarios, as well as Earth and pulsar term searches, and only Earth term searches. The results show that the estimation accuracy of the inclination angle and GW strain is lower in the evolving condition than in the non-evolving condition because the two parameters participate in the evolving process. In addition, we find that the parameters estimable relates to signal-to-noise ratio, which is beneficial for reducing the dimensionality in the search process. In summary, our method serves as a reference for exploring lower parameter limits under different conditions and assists in assessing the optimization of parameter estimation in GW detection algorithms. This helps lay the theoretical foundation for advances in the field of GWs and the optimization of PTAs. [ABSTRACT FROM AUTHOR]

BACKGROUND The use of trap crops can reduce the egg production of female Plutella xylostella in cruciferous vegetables and is an effective method for controlling this pest. To date, most of the trap plants that have been studied are cruciferous plants containing high concentrations of glucosinolates, which are more attractive to P. xylostella female adults. However, the application of these trap plants also has some limitations. Studies have shown that aqueous extracts of cruciferous plants can attract P. xylostella to lay eggs. In this study, we utilized the extract of Chinese kale to treat a non‐host plant, the faba bean, and evaluated the possibility of using it as a dead‐end trap plant for P. xylostella control. RESULTS: Plutella xylostella females laid significantly more eggs on faba beans that had been sprayed with the extract of Chinese kale rather than on Chinese kale itself. The first instar larvae of P. xylostella failed to survive on faba beans. Notably, the faba beans with the Chinese kale extract had the strongest attraction effect on P. xylostella females when placed 3 m away from the Chinese kale. Moreover, this attraction effect of faba beans on P. xylostella for oviposition lasted for up to 15 days. CONCLUSION: Faba bean plants sprayed with the aqueous extract of Chinese kale represent a potential dead‐end trap plant for P. xylostella adults and their oviposition while being invariably deadly for their offspring. The present study provides a new proof of concept of using a non‐cruciferous trap plant for P. xylostella management. [ABSTRACT FROM AUTHOR]

Odorant‐degrading enzymes (ODEs) have been found in insect antennae and play a critical role in signal chemical degradation once the message is conveyed. Significant progress has been made in characterizing ODEs in a variety of pests but very little is known in their natural enemies. We have carried out an antennae‐ and sex‐specific transcriptome of Aphidius gifuensis, a natural enemy of aphid, to identify the candidate ODEs. Based on the antennae‐ and sex‐specific transcriptome, a total of 100 putative ODEs were identified including one aldehyde oxidase (AOX), four alcohol dehydrogenases (ADs), eight UDP‐glucuronosyltransferases (UGTs), 45 cytochrome P450 (P450s), nine glutathione S‐transferases (GSTs) and 40 carboxylesterases (CCEs or CXEs). Additionally, we used RT‐qPCR to determine the expression profiles of these genes in tissues of both sexes. Based on the phylogenic analysis and tissue‐expression patterns, AgifEstE4, AgifCXE3, AgifCCE4, AgifCCE7, and AgifCCE18 were suggested as key ODEs in A. gifuensis. In addition, the female or male specifically enriched genes, such as AgifCCE17, AgifEstB1, AgifCYP18a1, AgifUGT2C2, were also considered to involve in the chemosensory processing in A. gifuensis. This study not only identified the candidate ODEs in A. gifuensis but also provided source for further exploration of the molecular mechanisms of chemical signal transductions in A. gifuensis, as well as other hymenopteran species. [ABSTRACT FROM AUTHOR]

The time dispersion effect affects the accuracy of solar time difference of arrival (TDOA) navigation. In this celestial autonomous navigation, Mars's moons are reflecting celestial bodies, and their shape affects the TDOA dispersion model. In the modelling process of traditional methods, the moons of Mars (Phobos and Deimos) are regarded as points, which causes the model to be inaccurate. In order to solve these problems, we simplified the Mars's moons into ellipsoids or solid diamonds, and then established a TDOA model with the nonspherical Mars's moons as reflecting celestial bodies through differential geometry and geometric optics. Finally, we analysed the time dispersion caused by the Mars's moons in theory. Theoretical analysis and experiments show that the point model error is 5·66 km, and the 3D model error is within 70 m. Thus, the 3D TDOA model established in this paper is meaningful. In addition, the Sun–Mars-moons–spacecraft angle, solar flare, three-axis length, and attitude of the Mars's moons have a great effect on the dispersion profile, while the Mars's moons-to-spacecraft distance has a small effect. [ABSTRACT FROM AUTHOR]

In natural ecological systems, plants are often simultaneously attacked by both insects and pathogens, which can affect each other’s performance and the interactions can be extended to higher trophic levels, such as parasitoids. The English grain aphid (Sitobion avenae) and powdery mildew (Blumeria graminis f. sp. tritici) are two common antagonists that pose a serious threat to wheat production. Numerous studies have investigated the effect of a single factor (insect or pathogen) on wheat production. However, investigation on the interactions among insect pests, pathogens, and parasitoids within the wheat crop system are rare. Furthermore, the influence of the fungicide, propiconazole, has been found to imitate the natural ecosystem. Therefore, this study investigated the effects of B. graminis on the biological performance of grain aphids and the orientation behavior of its endoparasitic wasp Aphidius gifuensis in the wheat system. Our findings indicated that B. graminis infection suppressed the feeding behavior, adult and nymph weight, and fecundity and prolonged the developmental time of S. avenae. We found that wheat host plants had decreased proportions of essential amino acids and higher content of sucrose following aggravated B. graminis infection. The contents of Pro and Gln increased in the wheat plant tissues after B. graminis infection. In addition, B. graminis infection elicited immune responses in wheat: increase in the expression of defense genes, content of total phenolic compounds, and activity of three related antioxidant enzymes. Moreover, co-infection of B. graminis and S. avenae increased the attraction to A. gifuensis compare to that after infestation with aphids alone. In conclusion, our results indicated that B. graminis infection adversely affected the performance of S. avenae in wheat through restricted nutrition and induced defense response. Furthermore, the preference of parasitoids in such an interactive environment might provide an important basis for pest management control. [ABSTRACT FROM AUTHOR]

The green peach aphid, Myzus persicae Sulzer (Hemiptera, Aphididae), is an important cosmopolitan pest. Real time qRT-PCR has been used for target gene expression analysis on M. persicae. Using real time qRT-PCR, the expression levels are normalized on the basis of the reliable reference genes. However, to date, the stability of available reference genes has been insufficient. In this study, we evaluated nine candidate reference genes from M. persicae under diverse experimental conditions. The tested candidate genes were comprehensively ranked based on five alternative methods (RefFinder, geNorm, Normfinder, BestKeeper and the comparative ΔCt method). 18s, Actin and ribosomal protein L27 ( L27) were recommended as the most stable reference genes for M. persicae, whereas ribosomal protein L27 ( L27) was found to be the least stable reference genes for abiotic studies (photoperiod, temperature and insecticide susceptibility). Our finding not only sheds light on establishing an accurate and reliable normalization of real time qRT-PCR data in M. persicae but also lays a solid foundation for further studies of M. persicae involving RNA interference and functional gene research. [ABSTRACT FROM AUTHOR]

Larvae of the diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae), have rich microbial communities inhabiting the gut, and these bacteria contribute to the fitness of the pest. In this study we evaluated the effects of five antibiotics (rifampicin, ampicillin, tetracycline, streptomycin sulfate and chloramphenicol) on the gut bacterial diversity of P. xylostella larvae. We screened five different concentrations for each antibiotic in a leaf disc assay, and found that rifampicin and streptomycin sulfate at 3 mg/mL significantly reduced the diversity of the bacterial community, and some bacterial species could be rapidly eliminated. The number of gut bacteria in the rifampicin group and streptomycin sulfate group decreased more rapidly than the others. With the increase of antibiotic concentration, the removal efficiency was improved, whereas toxic effects became more apparent. All antibiotics reduced larval growth and development, and eventually caused high mortality, malformation of the prepupae, and hindered pupation and adult emergence. Among the five antibiotics, tetracycline was the most toxic and streptomycin sulfate was a relatively mild one. Some dominant bacteria were not affected by feeding antibiotics alone. Denaturing gradient gel electrophoresis graph showed that the most abundant and diverse bacteria in P. xylostella larval gut appeared in the cabbage feeding group, and diet change and antibiotics intake influenced gut flora abundance. Species diversity was significantly reduced in the artificial diet and antibiotics treatment groups. After feeding on the artificial diet with rifampicin, streptomycin sulfate and their mixture for 10 days, larval gut bacteria could not be completely removed as detected with the agarose gel electrophoresis method. [ABSTRACT FROM AUTHOR]