排序方式: 共有66条查询结果,搜索用时 15 毫秒
51.
The two closely related moth species, Helicoverpa armigera and H. assulta, are sympatric in China. Both species use a mixture of (Z)-11-hexadecenal (Z11-16:Ald) and (Z)-9-hexadecenal (Z9-16:Ald) as their sex pheromones but in widely different ratios. Hybridization and backcrossing experiments between H. armigera and H. assulta were conducted and sex pheromone compositions of the parent species, their F(1) hybrids and backcrosses were compared to study the genetic basis of the production of their sex pheromone blend composition. Results show that the difference in sex pheromone blend ratios of these Helicoverpa species is mainly controlled by an autosomal locus with two alleles, with the allele from H. armigera being almost completely dominant over that derived from H. assulta. 相似文献
52.
Adaptations to suppress the viability of conspecifics may provide novel ways to control invasive taxa. The spread of cane toads (Rhinella marina) through tropical Australia has had severe ecological impacts, stimulating a search for biocontrol. Our experiments show that cane toad tadpoles produce waterborne chemical cues that suppress the viability of conspecifics encountering those cues during embryonic development. Brief (72 h) exposure to these cues in the egg and post-hatching phases massively reduced rates of survival and growth of larvae. Body sizes at metamorphosis (about three weeks later) were almost twice as great in control larvae as in tadpole-exposed larvae. The waterborne cue responsible for these effects might provide a weapon to reduce toad recruitment within the species' invaded range. 相似文献
53.
Investigation of Charge Carrier Behavior in High Performance Ternary Blend Polymer Solar Cells 下载免费PDF全文
Tack Ho Lee Mohammad Afsar Uddin Chengmei Zhong Seo‐Jin Ko Bright Walker Taehyo Kim Yung Jin Yoon Song Yi Park Alan J. Heeger Han Young Woo Jin Young Kim 《Liver Transplantation》2016,6(19)
This study demonstrates high‐performance, ternary‐blend polymer solar cells by modifying a binary blend bulk heterojunction (PPDT2FBT:PC71BM) with the addition of a ternary component, PPDT2CNBT. PPDT2CNBT is designed to have complementary absorption and deeper frontier energy levels compared to PPDT2FBT, while being based on the same polymeric backbone. A power conversion efficiency of 9.46% is achieved via improvements in both short‐circuit current density (JSC) and open‐circuit voltage (VOC). Interestingly, the VOC increases with increasing the PPDT2CNBT content in ternary blends. In‐depth studies using ultraviolet photoelectron spectroscopy and transient absorption spectroscopy indicate that the two polymers are not electronically homogeneous and function as discrete light harvesting species. The structural similarity between PPDT2CNBT and PPDT2FBT allows the merits of a ternary system to be fully utilized to enhance both JSC and VOC without detriment to fill‐factor via minimized disruption of semi‐crystalline morphology of binary PPDT2FBT:PC71BM blend. Further, by careful analysis, charge carrier transport in this ternary blend is clearly verified to follow parallel‐like behavior. 相似文献
54.
Ilaria Marabotti Andrea Morelli Lorenzo M. Orsini Elisa Martinelli Giancarlo Galli 《Biofouling》2013,29(6):481-493
Fouling-release coatings were prepared from blends of a fluorinated/siloxane copolymer with a poly(dimethyl siloxane) (PDMS) matrix in order to couple the low modulus character of PDMS with the low surface tension typical for fluorinated polymers. The content of the surface-active copolymer was varied in the blend over a broad range (0.15–10 wt % with respect to PDMS). X-ray photoelectron spectroscopy depth profiling analyses were performed on the coatings to establish the distribution of specific chemical constituents throughout the coatings, and proved enrichment in fluorine of the outermost layers of the coating surface. Addition of the fluorinated/siloxane copolymer to the PDMS matrix resulted in a concentration-dependent decrease in settlement of barnacle, Balanus amphitrite, cyprids. The release of young plants of Ulva, a soft fouling species, and young barnacles showed that adhesion strength on the fluorinated/siloxane copolymer was significantly lower than the siloxane control. However, differences in adhesion strength were not directly correlated with the concentration of copolymer in the blends. 相似文献
55.
T. SUBRAMONIAM 《Invertebrate reproduction & development.》2013,57(3):197-199
A peculiarity in the mating habit of E. asiatica resulting in deposition of spermato-phores on immature females has been described and interpreted as heterosexual raping. Pheromonal attraction of the male is apparently not involved, the copulation being indiscriminate. 相似文献
56.
M. C. A. Downham M. Tamò D. R. Hall B. Datinon S. Adetonah & D. I. Farman 《Entomologia Experimentalis et Applicata》2004,110(2):151-158
In previous work successful trapping of the legume podborer, Maruca vitrata Fabricius (Lepidoptera: Pyralidae), was accomplished using a synthetic pheromone blend consisting of (E,E)‐10,12‐hexadecadienal, (E,E)‐10,12‐hexadecadienol, and (E)‐10‐hexadecenal in a 100 : 5 : 5 ratio. In the present work, experiments were conducted in cowpea fields in Benin to compare different trap designs, and other aspects of the lures. A water‐trap made from a plastic jerry‐can was found to be superior to commercial funnel‐ and sticky‐trap designs, and 120 cm was the optimum height for captures. Generally, lures consisted of polyethylene vials containing 0.1 mg of pheromone. Results showed that shielding the lures from the adverse effects of sunlight with aluminium foil did not increase trap catches of M. vitrata. The degree of isomeric purity of the (E,E)‐10,12‐hexadecadienal and (E,E)‐10,12‐hexadecadienol blend components, in the range 73–99%, had no significant effect on captures, while lures of 80% isomeric purity showed no loss of effectiveness for up to 4 weeks. Similar results were observed with lures from a commercial source containing 0.46 mg of pheromone in the blend ratio 100 : 11 : 6 and 95% isomeric purity. Residue analysis showed that vial lures exposed for 2 weeks in the field still contained 73% of the initial amount of (E,E)‐10,12‐hexadecadienal, compared to rubber septa dispensers, which only retained 22%. Females comprised 11–50% of total catches, confirming earlier, unexpected results for synthetic lures. The observations that effective traps can be made from locally available plastic containers, and that pheromone blend composition and purity are not critical, should reduce costs and improve the feasibility of traps as practical monitoring tools for M. vitrata. 相似文献
57.
Marianna Boi Marina Quartu Maria Pina Serra Paolo Solari Tiziana Melis Marina Del Fiacco 《Journal of morphology》2009,270(4):442-450
The morphological features of the glandular epithelium that secretes pheromone in the polyphagous pest gypsy moth Lymantria dispar are described by light and electron microscopy. The monolayered gland cells are covered by the folded cuticle of the intersegmental membrane between the 8th and 9th abdominal segments showing neither sites of discontinuity nor distinct openings on its external surface. The cells bear a large, often irregularly shaped nucleus, and contain granules of variable amount and electron‐density. These granules are mostly located in the basal compartment of the cytoplasm, in a labyrinthine zone laying on a basement membrane. The apical membrane of the gland cells bear microvilli and cell–cell contact is established by different junctional structures. Nerve fibers enwrapped in glia are found beneath the basement membrane, in close contact with the secretory cells. This latter finding represents the first evidence of the innervation of the pheromonal gland in L. dispar. J. Morphol. 2009. © 2008 Wiley‐Liss, Inc. 相似文献
58.
不同配方信息素诱芯对二化螟的诱捕效果比较研究 总被引:3,自引:0,他引:3
2004年和2005年夏季在江淮稻区二化螟Chilo suppressalis性诱剂诱捕的结果表明:一种新型诱芯(其中顺-11-十六碳烯醛∶顺-9-十六碳烯醛为2∶1)对第1代二化螟的日平均诱捕量相当于二化螟标准诱芯的5倍左右,而在越冬代和第2代成虫发生期则分别相当于后者的1.5839倍和1.7474倍。二化螟诱捕量取决于顺-11-十六碳烯醛和顺-9-十六碳烯醛的比例,而与其各自的剂量或信息素总剂量无明显关系,且它们的最佳配比可能因世代夜间温度的不同而不同,二化螟标准诱芯在第1代诱捕效果下降的原因可能是两种不饱和十六醛比例不适。 相似文献
59.
During host plant selection and particularly after alighting on a plant, chemical cues from the plant surface influence an insect's acceptance of the plant and, subsequently, its egg‐laying behaviour. Primary metabolites in the phylloplane may be more important than hitherto known. We have shown that soluble carbohydrates, such as glucose, fructose, and sucrose, and sugar alcohols, such as sorbitol, quebrachitol, and myo‐inositol, can be detected by insects after contacting the plant and that they positively influence egg‐laying of the codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), on apple trees. We addressed the question whether a lack of these substances could also explain apple tree resistance to C. pomonella in terms of reduced egg‐laying. Leaf surface washings were collected in an apple orchard by spraying water on the resistant cultivar X65‐11 and on the susceptible cultivar P5R50A4. The washings were tested on a nylon cloth on isolated females under no‐choice conditions. The washings were analysed and synthetic blends, each consisting of the six metabolites in the proportions established in the leaf surface washings of both cultivars, were then tested for their effect on egg‐laying of C. pomonella. Dose–response egg‐laying tests were carried out on substrates impregnated with the X65‐11 leaf surface blend at 1, 100, 1 000, and 10 000 times the natural dose. Egg‐laying behaviour in the bioassays with leaf surface washings of both cultivars closely resembled egg‐laying in the orchard. Washings of P5R50A4 stimulated egg‐laying to a greater extent than those of X65‐11 and the water control. Synthetic blends reduced substrate acceptance and egg‐laying, compared to the washings of X65‐11. Ratios between components within the blend are responsible for this resistance. In conclusion, quantities and ratios of the six primary metabolites found on the leaf surface may influence host preference of C. pomonella as well as their egg‐laying behaviour, thus they may play a role in the trees’ resistance to the codling moth. 相似文献
60.
From Binary to Ternary: Improving the External Quantum Efficiency of Small‐Molecule Acceptor‐Based Polymer Solar Cells with a Minute Amount of Fullerene Sensitization 下载免费PDF全文
Yu Chen Yunpeng Qin Yang Wu Cheng Li Huifeng Yao Ningning Liang Xiaochen Wang Weiwei Li Wei Ma Jianhui Hou 《Liver Transplantation》2017,7(17)
Ternary blend is proved to be a potential contender for achieving high efficiency in organic photovoltaics, which can apparently strengthen the absorption of active layer so as to better harvest light irradiation. Much of the previous work in ternary polymer solar cells focuses on broadening the absorption spectrum; however, a new insight is brought to study the third component, which in tiny amounts influents the small‐molecule acceptor‐based device performance. Without contributing to complementing the absorption, a minute amount of fullerene derivative, Bis‐PC70BM, can effectively play an impressive role as sensitizer in enhancing the external quantum efficiency of the host binary blend, especially for polymeric donor. Detailed investigations reveal that the minute addition of Bis‐PC70BM can realize morphology modification as well as facilitate electron transfer from polymeric donor to small molecule acceptor via cascade energy level modulation, and therefore lead to an improvement in device efficiency. 相似文献