利用苦瓜子衣制备食用色素的研究

对苦瓜子衣色素的提取工艺及安全性进行了研究,确定了最佳提取工艺条件为:用乙醚作提取剂,提取剂用量为1∶40g/ml,提取时间为20min,提取温度为20℃,提取次数为2次。毒性试验表明:该色素的毒性很低,主要有毒元素的含量为Pb<2.0ppm、As<2.0ppm、Hg<0.01ppm。     

Interspecific aggression in colonies of the slave-making ant Harpagoxenus sublaevis

Colonies of the slave-making ant, Harpagoxenus sublaevis, may simultaneously contain workers of several Leptothorax slave species. We observed aggressive interactions among slave-makers, between slavemakers and slaves, and among slaves in 11 mixed colonies. The first two types of aggression appear to be correlated with reproductive competition for the production of males. Aggressive interactions among slaves, however, occurred mainly between slaves belonging to different species. In two colonies, in which one slave species clearly outnumbered the other, the majority attacked and finally expelled all nestmates belonging to the minority species. Our observations thus suggest that in Harpagoxenus colonies a homogeneous colony odor is not always achieved and that heterospecific slaves may occasionally be mistaken for alien ants. Gas chromatographic analyses of ants from mixed colonies similarly show that cuticular hydrocarbon profiles may differ strongly between heterospecific nestmate slaves.     

Trail pheromones and Dufour gland contents in three <Emphasis Type="Italic">Camponotus</Emphasis> species (<Emphasis Type="Italic">C. castaneus,C. balzani,C. sericeiventris</Emphasis>: Formicidae,Hymenoptera)

Summary. By means of gas chromatography, gas chromatographic coupled mass spectrometry and behavioral analysis the major trail pheromone components from the hindgut of the formicine species Camponotus castaneus, C. balzani and C. sericeiventris were identified. The trail pheromone of C. castaneus is 3,5-dimethyl-6-(1-methylpropyl)- tetrahydro-2H-pyran- 2-one, and that of the other two species is 3,4-dihydro-8-hydroxy-3,5,7-trimethylisocoumarin. Although both compounds release precise trail following behavior in the respective species, the major recruitment signal in the three Camponotus species appears to be formic acid discharged from the poison gland. The composition of the Dufour gland secretions of C. castaneus and C. sericeiventris is similar, but that of the hypertrophied Dufour gland of C. balzani is very different from any other Camponotus Dufour gland content described up to date: it contains large amounts of esters, the major compound of which is octyl hexanoate, which makes up 97% a/a of the total volatiles.     

Vibrational communication between hitchhikers and foragers in leaf-cutting ants (Atta cephalotes)

Abstract In a foraging column of the leaf-cutting ant Atta cephalotes, minim workers (the smallest worker subcaste) hitchhike on leaf fragments carried by larger workers. It has been demonstrated that they defend leaf carriers against parasitic phorid flies. The present study examines the cues used by the potential hitchhikers to locate leaf carriers. As recently reported, foraging workers stridulate while cutting a leaf fragment, and the stridulatory vibrations serve as closerange recruitment signals. We tested the hypothesis that these plant-borne stridulatory vibrations are used by the potential hitchhikers to locate workers engaged in cutting. Three different lines of evidence support this view. Firstly, the repetition rate of the stridulations produced by foraging workers increases significantly as foragers maneuver the leaf fragment into the carrying position and walk loaded to the nest. This is the moment when hitchhikers usually climb on the leaf. Although the leaf-borne stridulatory vibrations are considerably attenuated when transmitted through the workers' legs, they can nevertheless be detected at short distances by minims. This subcaste is several times more sensitive to substrate-borne vibrations than larger workers. Secondly, when a stridulating and a silent leaf were simultaneously presented at the foraging site, minim workers spent significantly more time on the stridulating than on the silent leaf. Thirdly, hitchhiking was more frequent in leaf carriers which cut fragments out of the stridulating leaf than in those cutting the silent leaf.Abstract In a foraging column of the leaf-cutting ant Atta cephalotes, minim workers (the smallest worker subcaste) hitchhike on leaf fragments carried by larger workers. It has been demonstrated that they defend leaf carriers against parasitic phorid flies. The present study examines the cues used by the potential hitchhikers to locate leaf carriers. As recently reported, foraging workers stridulate while cutting a leaf fragment, and the stridulatory vibrations serve as closerange recruitment signals. We tested the hypothesis that these plant-borne stridulatory vibrations are used by the potential hitchhikers to locate workers engaged in cutting. Three different lines of evidence support this view. Firstly, the repetition rate of the stridulations produced by foraging workers increases significantly as foragers maneuver the leaf fragment into the carrying position and walk loaded to the nest. This is the moment when hitchhikers usually climb on the leaf. Although the leaf-borne stridulatory vibrations are considerably attenuated when transmitted through the workers' legs, they can nevertheless be detected at short distances by minims. This subcaste is several times more sensitive to substrate-borne vibrations than larger workers. Secondly, when a stridulating and a silent leaf were simultaneously presented at the foraging site, minim workers spent significantly more time on the stridulating than on the silent leaf. Thirdly, hitchhiking was more frequent in leaf carriers which cut fragments out of the stridulating leaf than in those cutting the silent leaf.Communicated by P. Pamilo     

无公害食用菌生产技术规程的制定研究

通过分析近年来我国食用菌生产管理和产品质量安全存在的问题,论述了开展无公害食用菌生产的重要性.同时吸收各地的生产经验.根据国家有关标准,从食用菌生产场所的选择、培养基材料和水的要求、栽培管理、病虫害防治、采后处理、加工贮藏和产品质量安全检测等几个方面,提出了一整套较系统的无公害食用菌生产技术操作规程.该项技术规程在生产上的推广应用,对提高食用菌生产技术水平、改善和保障食用菌产品质量、增强产品在国际市场的竞争力将产生积极的推动作用.     

上海食用鱼中短链氯化石蜡的污染特征

为了解长三角地区食用鱼中短链氯化石蜡(SCCPs)的污染特征,根据当地人的食鱼习惯,在上海采集了不同营养级的食用鱼8种,共计68尾,测定了肌肉中SCCPs含量并分析了其同族体的分布模式.结果表明,食用鱼肌肉中SCCPs的含量(干重,dw)范围为36～801 ng.g-1;同族体分布以C10-和C11-SCCPs为主,随着碳链长度的增加,SCCPs同族体含量所占比例随之降低,并且均以低氯(Cl6～Cl8)取代的SCCPs为主要组成部分,相对丰度之和占总丰度的61.46%～82.50%.上海食用鱼中SCCPs的含量在世界范围内处于中等水平,其分布模式与国内外研究一致.     

The Effects of Site Conditions and Mitigation Practices on Success of Establishing the Valley Elderberry Longhorn Beetle and Its Host Plant,Blue Elderberry

This study performed the first systematic evaluation of the success of habitat mitigation at establishing the threatened Valley elderberry longhorn beetle (Desmocerus californicus dimorphus) and its host plant, blue elderberry (Sambucus mexicana). Habitat mitigation performed through enforcement of the U.S. Endangered Species Act represents a tightly controlled form of habitat restoration, facilitating the evaluation of restoration practice. Restoration plantings of blue elderberry have been substantial in our study area, the Central Valley of California. Surveys of 30 mitigation sites and 16 nearby natural sites showed that mitigation sites were a fraction of the size of natural habitat areas (mean = 24%) and contained smaller shrubs. The beetle colonized 53% of mitigation sites and its populations were denser in sites with moderate levels of dead stems on elderberry shrubs, and moderate damage to elderberry stems and bark. This likely indicates that the beetle responds to stressed shrubs, which are likely to contain elevated levels of nitrogen. Beetle density also increased with the size and age of mitigation sites. This indicates a need to make restoration sites as large as possible and to monitor these sites for longer than current guidelines suggest, thereby allowing more time for convergence of natural and mitigation sites. Few factors examined here directly influenced the growth of elderberry shrubs, but elderberry grew more rapidly in sites closer to riparian areas, indicating that such sites should be favored for mitigation sites.