Development and use of parasitoids (Hymenoptera : Aphidiidae & Aphelinidae) for biological control of aphids in China

A review of aphid parasitoids in China with special emphasis on their production, utilization, and conservation is presented with a brief history of Chinese biological control. Twenty genera, 99 species of Aphidiidae and two genera, 11 species of Aphelinidae were recorded in China. Each parasitoid is listed with a brief description of aphids, host plants, areas of study such as taxonomy, biology, bionomics, geographic distribution, rearing, and literature citations. Achievements, status, and problems in aphid parasitoid production, utilization, conservation, and future prospects are detailed for dominant aphid parasitoids such as Aphidius gifuensis Ashmead, A. ervi Haliday and Aphelinus mali Haldeman. Finally, opportunities and challenges of commercialization commercialization of natural enemies, especially aphid parasitoids, in China, are analyzed and discussed.

CO2浓度升高对三种树木叶片化学和舞毒蛾幼虫取食及生长的影响

探讨全球气候变化的生物学和生态学效应是当今生态学中的热点，研究大气CO2浓度升高对植物-昆虫相互作用关系的影响具有重要的理论和实践意义。本文使用开顶式气室（Open-top chamber，OTC）在野外条件下研究了CO2浓度升高对三种树木（小青杨、白桦和蒙古栎）叶片化学成分含量的影响，以及树木叶片品质变化对一种广食性森林昆虫（舞毒蛾）幼虫取食、生长发育和取食偏嗜性的影响。得出如下结果：（1）CO2浓度升高对3个受试树种叶片中的营养成分及次生代谢物含量均有显著影响，总体表现为氮含量降低，而碳氮比、非结构性碳水化合物、总酚和缩合丹宁含量增加。叶片中的化学成分含量可随时间发生显著变化，不同树种、甚至同一树种不同冠层高度的叶片对CO2浓度升高的响应强度也是不同的。叶片的干物质含量和比叶重对CO2浓度升高的响应不显著。（2）室内非选择性取食实验、室内选择性取食实验以及上树取食饲养方式下的多龄期取食实验，均发现高浓度CO2处理组内舞毒蛾幼虫的生长发育受到显著抑制。但对四龄舞毒蛾幼虫所进行的短期生物测定并未发现不同CO2浓度处理下幼虫的生长发育速率、对食物的取食率和转化率等昆虫营养指标存在显著差异。（3）叶片品质的降低是导致舞毒蛾幼虫生长发育受抑制的主要原因。但是总体上，CO2浓度升高导致的叶片品质变化并未显著影响幼虫的取食率和取食量。（4）舞毒蛾幼虫对不同叶片种类表现出清晰的取食选择性，这种选择性在其幼龄期就可表现出来。幼虫对小青杨上层叶片有最显著的偏嗜性，对蒙古栎下层叶片有最明显的拒食性。但是CO2浓度升高导致的叶片品质变化对舞毒蛾幼虫的取食选择性和寄主偏嗜行为并未产生显著影响。（5）检测出高浓度CO2处理组内舞毒蛾幼虫虫粪中含有浓度更高的植物次生代谢物质（总酚和缩合单宁），这很可能是昆虫整体生长发育受抑制的重要原因之一。

Responses of Artemisia frigida Willd. (Compositae) and Leymus chinensis (Trin.) Tzvel. (Poaceae) to sheep saliva

Although studies show that grazing and browsing by herbivores have marked effects on host plants, the mechanisms remain unclear. The objective of this study is to determine the effects of sheep saliva on host plant growth. Sheep saliva was manually applied to clipped plants of two different life forms, a semi-shrub, Artemisia frigida Willd., and a herbaceous species, Leymus chinensis (Trin.) Tzevel. The results showed that sheep saliva significantly enhanced aboveground net primary productivity (ANPP) and the ratio of ANPP to belowground net primary productivity (BNPP) for both species. This indicated that sheep saliva promotes aboveground compensatory growth and allocation of photosynthate to aboveground for both plant species. Sheep saliva stimulated only tillering of L. chinensis. Regardless of saliva application, clipping significantly decreased BNPP and plant height, but significantly increased the number of branches or tillers for both plant species. The relative growth rates (RGRs) on both species were significantly greater after clipping with saliva compared with control and clipping without saliva treatments. In addition, RGR of the herbaceous species L. chinensis was faster than that of the semi-shrub A. frigida after application of saliva. (c) 2006 Elsevier Ltd. All rights reserved.

Morphological and reproductive response of Caragana microphylla to different stocking rates

Understanding the effect on host plants of defending against herbivores is important in grazing ecology and grassland management. In this study, the morphological and reproductive responses of Caragana microphylla Lam. to grazing sheep were investigated using a 15-year grazing experiment with six stocking rates in the Inner Mongolia steppe of China. Plant height, rachis length, leaflet size, and number of pods decreased significantly, whereas spine density and length increased significantly with increased stocking rate. Significant negative correlations were observed between production of vegetative and reproductive organs and defensive organs, indicating that it is costly for C. microphylla to defend against herbivores and that morphological miniaturization and a tradeoff between production and defense were main responses of C. microphylla to herbivores. (c) 2006 Elsevier Ltd. All rights reserved.

Influence of leaf tissue structure on host feeding selection by pea leaf miner Liriomyza huidobrensis (Diptera : Agromyzidae)

Host feeding selection by the female pea leafminer, Liriomyza huidobrensis, on 47 species of plants was studied. The leaves were sectioned by microtome, and 15 characteristics of the leaf tissue structure were measured under a microscope. Correlation analysis between host feeding selection and leaf tissue structure indicated that the preference of host feeding selection was positively correlated with the percentage of moisture content of leaves and negatively with thickness of the epidermis wall, and densities of the palisade and spongy tissues of leaves. Leaf tissue structure was influential in feeding and probing behavior of female L. huidobrensis. So, thickness of epidermis wall, densities of the palisade and spongy tissues can act as a physical barrier to female oviposition. Furthermore, higher densities of palisade and spongy tissues can be considered a resistant trait which affects mining of leaf miner larvae as well. As a result, plants with lower leaf moisture content may not be suitable for the development of L. huidobrensis.

Host dependent frequency upconversion of Yb3+/Tm3+-codoped oxyfluoride tellurite glasses

The upconversion luminescence properties of Yb3+/Tm3+-codoped oxyfluoride tellurite glasses under 980 nm excitation are investigated experimentally. The intense blue and relatively weak red emissions centered at 475 and 649 nm corresponding to the transitions (1)G(4) -> H-3(6) and (1)G(4) -> H-3(4) of Tm3+, respectively, are simultaneously observed at room temperature. The effect of PbF2 on upconversion intensity is observed and discussed, and possible upconversion mechanisms are evaluated. The intense blue upconversion luminescence of Yb3+/Tm3+-codoped oxyfluoride tellurite glasses may be a potentially useful material for developing blue upconversion optical devices. (c) 2005 Elsevier B.V. All rights reserved.

Host dependent thermal stability and frequency upconversion of Er3+-doped heavy metal oxyfluoride germanate glasses

The upconversion properties of Er3+-doped heavy metal oxyfluoride germanate glasses under 975 nm excitation have been investigated. The intense green (551 and 529 nm) and relatively weak red (657 nm) emissions corresponding to the transitions S-4(3/2) -> I-4(15/2), H-2(11/2) -> I-4(15/2) and F-4(9/2) -> I-4(15/2), respectively, were simultaneously observed at room temperature. The content of PbF2 has an important influence on the upconversion luminescence emission. With increasing content of PbF2, the intensities of green (529 nm) and red (657 nm) emissions increase slightly, while the green emission (551 nm) increases markedly. These results suggest that PbF2 has an influence on the green (551 nm) emission more than on the green (529 nm) and red (657 nm) emissions.

Host dependent frequency upconversion of Er3+-doped oxyfluoride germanate glass

Er3+-doped oxyfluoride germanate glasses have been synthesized by the conventional melting and quenching method. The Judd-Ofelt intensity parameters were calculated based on the Judd-Ofelt theory and absorption spectra measurements. With the substitution of PbF2 for PbO, the Omega(2) parameter decreases, while the Omega(6) parameter increases. These change trends indicate that fluoride anions come to coordinate erbium cations and the covalency of the Er-O bond decreases. Structural and thermal stability properties were obtained by Raman spectra and differential thermal analysis, indicating that PbF2 plays an important role in the formation of glass network and has an important influence on the maximum phonon energy and thermal stability of host glasses. Intense green and red emissions centered at 525, 546, and 657 nm, corresponding to the transitions H-2(11/2) -> I-4(15/2), S-4(3/2) -> I-4(15/2), and F-4(9/2) -> I-4(15/2), respectively, were simultaneously observed at room temperature. With increasing PbF2 content, the intensity of red (657nm) emissions increases significantly, while that of the green (525 and 546nm) emission increases slightly. The results indicate that PbF, has more influence on the red (657nm) emission than the green (525 and 546nm) emissions in oxyfluoride germanate glasses. The possible upconversion luminescence mechanisms have also been estimated and discussed. (c) 2005 Elsevier B.V. All rights reserved.

Holmium laser in-band pumped by a thulium laser in the same host of YAlO3

We report on the room-temperature continuous-wave (CW) operation of a Ho:YAlO3 laser that is resonantly end pumped at 1.94 mu m by a diode-pumped thulium-doped laser in the same host. Through the use of a 1 at % Ho3+-doped 20-mm-long YAlO3 crystal (b cut), the Ho:YAlO3 laser generated 1 W of linearly polarized (E//c) output at 2118 nm and 0.55 W of E//a output at 2128.5 nm for an incident pump power of 5 W, with an output coupler transmission of 14 and 3%, respectively. An optical-to-optical conversion efficiency of 20% and a slope efficiency of 33% were achieved at 2118 nm corresponding to an incident pump power.