蒙脱石、铁氧化物及其复合体对水中As(Ⅲ)的吸附效果

利用蒙脱石、FeCl_3·6H_2O制备出改性蒙脱石复合体,并对蒙脱石、铁氧化物及其改性复合体吸附水中As(Ⅲ)的效能进行对比试验。结果表明:这3者对水中As(Ⅲ)的吸附动力学均符合Lagergren速度模型,且均属于Freundlich等温吸附。复合体的沉降效率明显优于其他2种吸附剂,且对含As(Ⅲ)溶液的pH值具有很好调节能力。SO_4~(2-)和Mg~(2+)浓度对As(Ⅲ)的去除基本无影响,Ca~(2+)能促进As(Ⅲ)的吸附,NO_3~-、PO_4~(3-)与As(Ⅲ)存在较强的竞争吸附。     

青稞β—1，3—葡聚糖酶Ⅱ基因启动子的克隆分析及表达载体的构建

根据本实验室克隆并公布的藏青稞β—1，3—葡聚糖酶Ⅱ(BGH Ⅱ)基因序列，以藏青稞QB09基因组DNA为模板，构建DNA步移文库，并通过步移技术克隆出BGH Ⅱ起始密码子上游调控序列BGHP．鉴定和分析表明，BGHP具备大多数高等植物启动子的保守元件，预测它对BGHⅡ基因的表达具有一定的作用．为鉴定BGHⅡ基因的基本启动子元件，将基因5′侧翼序列做缺失片段分析，利用PCR方法从BGHP中得到3个不同大小两端带有Hind Ⅲ、BamH I酶切位点的片段BGHP1、BGHP2和BGHP3，定向插人载体pMGFP4(pBI221改建，报告基因为GFP)中，取代原有的CaMV35S启动子，构建了由驱动报告基因GFP的植物表达载体BGHPVl、BGHPV2和BGHPV3，用于大麦的遗传转化，为进一步研究其功能奠定了基础．图5表1参15     

从水稻种子表面分离的紫云英根瘤菌与不同水稻品种亲合性的研究

采用紫云英琼脂管结瘤试验，在10个供试的不同水稻品种中，仅从“汕优63”和“珍A一代”2个品种的种子表面各分离筛选到在紫云英上结瘤较早且较多的1个菌株，分别命名为SY63－4和SA1D－3。采用无菌盆栽试验分别将这2个菌株接种于4个不同水稻品种“汕优63”、“珍A一代”、“马协63”及“博湛优19”，发现菌株ZA1D－3对4种水稻均表现出显著的促生作用，SY63－4仅对“汕优63”和“珍A一代”表现出明显的促生作用。利用MPN法检测不同水稻品种根内外根瘤菌ZA1D－3和SY63－4的数量，发现ZA1D－3和SY63－4在4种水稻根部的定殖数量也不相同。SY63－4在“汕优63”根部定殖的数量log(ncfumFW^-1/g^-1)为5．20，比在其余3种水稻根部高出2个数量级；ZA1D－3在“珍A一代”根部定殖的最大数量log(ncfumFW^-1/g^-1)为4．54，比在其余3种水稻根部高出1个数量级。这说明SY63－4与“汕优63”，ZA1D－3与“珍A一代”间存在着一定的亲和性。图1表2参12     

Fe(Ⅲ)-Salen功能化纳米Fe_3O_4复合材料的合成及其对三氯苯的催化降解性能

采用溶剂热制备了氨基功能化纳米Fe_3O_4磁性复合材料(NH2-nFe_3O_4),并进一步通过缩合、配位等反应得到Fe(Ⅲ)-Salen功能化纳米Fe_3O_4复合材料(nFe_3O_4@Fe(Ⅲ)Salen).通过元素分析(EA)、X-射线衍射(XRD)、红外光谱(FTIR)、透射电镜(TEM)、振动样品磁强计(VSM)等手段对其进行了组成、结构、形貌、磁性等表征.结果表明,nFe_3O_4@Fe(Ⅲ)Salen平均粒径为约200 nm,饱和磁化强度为24.8 emu·g-1.催化剂为nFe_3O_4@Fe(Ⅲ)Salen,研究了其在可见光/H_2O_2类Fenton体系催化降解水中2,4,6-三氯酚(2,4,6-TCP)的性能.研究发现,当nFe_3O_4@Fe(Ⅲ)Salen用量≥0.8 g·L~(-1),溶液pH值为4.0—7.0,H_2O_2浓度为8.16—40.8 mmol·L~(-1)时,nFe_3O_4@Fe(Ⅲ)Salen/H_2O_2/可见光体系可以实现对浓度50.0 mg·L~(-1)(253.2 mg·L~(-1))的TCP溶液在5 min内近100%降解,较普通Fenton反应体系有更宽的pH适用范围.循环使用5次后,该催化体系对TCP的降解率仍能保持95%以上,nFe_3O_4@Fe(Ⅲ)Salen是有优异潜力的水中TCP绿色催化剂.     

TiO2光催化降解乙酰甲胺磷

在TiO2悬浮体系中,利用光催化技术消除乙酰甲胺磷(DMAPT).探索了催化剂用量和目标物浓度对消除速率的影响.结果表明,催化剂的最佳用量为4g·l-1,DMAPT的光催化降解规律符合L-H模型,吸附常数和反应速率参数分别为2mmol-1·l和0.6mmol·l-1·min-1.反应中主要的活性物种为·OH.反应的主要中间产物和矿化产物有O,S-二甲基硫代磷酰胺酯,O,O',S-三甲基硫代磷酸酯和磷酸甲酯等.DMAPT的降解从C-N键的断裂开始,随后经过P-N,P-S,P-C键的氧化分解,生成低毒和无毒的中间产物,并随着反应的继续最终达到彻底矿化,最终产物为SO2-4,NO-3,PO3-4和CO2.     

产甲烷条件下吲哚类有机物的降解途径

产甲烷条件下从废水污泥中驯化的细菌对吲哚的降解包括两步羰基化反应，生成中间产物氧化吲哚和靛红。本文研究了产甲烷条件下细菌降解吲哚类有机物的能力。在所研究的吲哚类化合物中，细菌在产甲烷条件下可以降解3－甲基吲哚和3－吲哚醋酸酯。氧化吲哚，3－甲基化吲哚和羰基吲哚分别为吲哚，3－甲基吲哚和3－吲哚醋酸酯的代谢产物，产甲烷条件下细菌可降解氧化吲哚并生成中间产物靛红，这证明了在吲哚降解过程中，吲哚吡咯环在2，3位碳间断裂之间连续进行了两步羰基化，吲哚1位和2位上甲基的存在，抑制了羰基化反应，3－甲基吲哚可在2位上羰基化，但不能在3位上羰基化，所以不能通过氧化吲哚－靛红途径进行代谢。3－吲哚醋酸酯的脱乙酰产物－羰基吲哚也不能在2位上羰基化，所以不能被进一步代谢。当3位上有H原子或供电子基团时，羰基化可在2位上进行，但3位上的吸电子取代基团会抑制羰基化。表1图4参25     

热力学平衡模拟研究Am(Ⅲ)的人体毒性

模拟研究了Am3 在胃液、汗液、组织液、细胞液和尿液中的形态分布及pH值和[Am]对形态分布的影响.结果表明,在胃液中,当[Am]=1×10-7mol·1-1,pH＜2.9时,Am(Ⅲ)主要以水溶性Am3 ,[AmCl]2 和[AmH2PO4]2 形态存在,随pH值的增高,固相AmPO4含量逐渐占据主导地位,而且随[Am]的增加而升高.汗液中,当[Am]=1×10-7mol.1-1时,在pH 4.2-7.5范围内,Am(Ⅲ)主要以各种可溶的形态存在,在pH 6.5,[Am]＜3×10-10mol.1-1或[Am]＞5×10-3mol·1-1时,Am(Ⅲ)主要以Am3 和[AmOH]2 形态存在.组织液中,当[Am]＞1×10-12mol·1-1时,Am(Ⅲ)主要以AmPO4存在,但在组织液中加入EDTA后,Am(Ⅲ)便以可排出体外的[AmEDTA]-形态存在.细胞液中,当pH为7.0时,即使[Am]为4×10-12mol·1-1,Am(Ⅲ)仍主要以固相AmPO4存在,提示Am(Ⅲ)有高的细胞毒性,另外,随pH值降低,固相含量降低,说明肺巨噬细胞摄取的Am(Ⅲ)气溶胶可逐渐释放到人体组织液中.当[Am]=1×10-10mol·1-1,pH＜4.5时,尿液中的Am(Ⅲ)以可溶于水的形态存在,但当pH＞4.5时,则主要以固相AmPO4形式存在,说明可通过降低尿液pH促进肾脏.Am(Ⅲ)排泄.     

冬虫夏草中一株内生菌次级代谢产物的化学成分

对一株冬虫夏草内生真菌Penicillium herquei发酵液次级代谢产物乙酸乙酯萃取部位的化学成分进行研究.利用柱色谱、制备色谱等手段进行分离纯化,并利用NMR、ESI-MS等波谱手段对化合物进行结构鉴定.分离了11个化合物,鉴定为2′,4′-二羟基-3′,5′-二甲基苯乙酮(1),香草醛(2),3-氧代-α-紫罗兰酮(3),3,3,5-三甲基-4-(3-氧代-1-丁烯基)-1-环己酮(4),对羟基苯甲醛(5),对羟基苯乙酮(6),对羟基苯乙酸甲酯(7),环(脯氨酸-异亮氨酸)(8),环(脯氨酸-缬氨酸)(9),4-甲氧基苯乙酸(10),环(4-甲基脯氨酸-缬氨酸)(11).本研究表明苯甲醛类、紫罗兰酮类和环二肽类化合物为冬虫夏草内生菌P. herquei的主要次级代谢产物.     

极端嗜热菌海栖热袍菌木聚糖酶B的克隆和表达

极端嗜热菌海栖热袍菌MSB8(ThermotogamaritimaMSB8)能够利用木聚糖代谢 ,并具有两个产木聚糖酶的基因 .本研究首次克隆和在大肠杆菌中表达海栖热袍菌MSB8的第 2个木聚糖酶基因即xynB基因 .以基因组DNA为模板 ,根据xynB基因的全序列设计了两对引物 ,在合适的PCR反应条件下有效地扩增出了xynB基因片段 .选用pET2 8a(+)表达载体 ,NcoI-HindⅢ酶切位点并编码了羧基端 6×His标签的阳性克隆表达成可溶且具有生物活性的蛋白质 .xynB结构基因由 10 4 4对碱基组成 ,编码 347个氨基酸 .根据已知木聚糖酶蛋白质氨基酸的同源性分析 ,XynB与T .sp.strainFjSS3-B .1的XynA的同源性最大 ,为 85 % ,与T .neapolitana的XynB同源性次之 ,为 82 % ,与其它木聚糖酶的同源性小于 4 3% .另外 ,XynB属于F/ 10族木聚糖酶 ,且含有单一功能区 .表 3图 3参 12     

新农药氯虫酰胺在醇液中的光解

分别以氙灯和紫外灯为光源,对氯虫酰胺在甲醇和乙醇中的光解动力学及降解机理进行了研究。结果表明,在氙灯和紫外照射下,氯虫酰胺在甲醇和乙醇中的光解符合一级反应动力学规律。在模拟太阳光氙灯辐射下,氯虫酰胺在甲醇和乙醇中的光解半衰期分别为1．58h和2．57h,而紫外光辐射下分别为1．49min和1．60min。采用LC-MS对氯虫酰胺光解产物进行分离和鉴定,推断氯虫酰胺在醇中的光解途径主要涉及到分子环合和重排生成光解产物A[2-（2-溴-4H-吡唑并[1,5．d]吡啶并[3,2-b]B,4]恶嗪-4-基亚氨基）-5-氯-N,3-二甲基苯甲酰胺]和B[2-（3-溴-1-（3-羟基吡啶-2-基）-1H-吡唑-5-基）-6-氯-3,8-二甲基喹啉-4（3H）-酮1。     

Representation of the world's biophysical conditions by the global protected area network

Protected areas (PAs) are often implemented without consideration of already existing PAs, which is likely to cause an overrepresentation of certain biophysical conditions. We assessed the representativeness of the current PA network with regard to the world's biophysical conditions to highlight which conditions are underprotected and where these conditions are located. We overlaid terrestrial and marine PAs with information on biophysical conditions (e.g., temperature, precipitation, and elevation) and then quantified the percentage of area covered by the PA network. For 1 variable at a time in the terrestrial realm, high temperature, low precipitation, and medium and very high elevation were underrepresented. For the marine realm, low and medium sea surface temperature (SST), medium and high sea surface salinity (SSS), and the deep sea were underrepresented. Overall, protection was evenly distributed for elevation across the terrestrial realm and SST across the marine realm. For 2 variables at a time, cold and very dry terrestrial environments had mostly low protection, which was also the case for low SST and low and medium SSS across most depths for marine environments. Low protection occurred mostly in the Sahara and the Arabian Peninsula for the terrestrial realm and along the Tropic of Capricorn and toward the poles for the marine realm. Although biodiversity measures are of prime importance for the design of PA networks, highlighting biophysical gaps in current PAs adds a frequently overlooked perspective. These gaps may weaken the potential of PAs to conserve biodiversity. Thus, our results may provide useful insights for researchers, practitioners, and policy makers to establish a more comprehensive global PA network.     

Quantitative composition of the defensive secretion ofBledius species (Coleoptera: Staphylinidae: Oxytelinae) is adapted to naturally occurring predators

Summary The adaptation of defensive secretions to their target organisms was examined for the abdominal gland secretions ofBledius furcatus, B. spectabilis andB. arenarius. Therefore the target organisms of the secretion of theseBledius species (i.e. their predators) had to be identified. At the collection sites examined these were the earwigLabidura riparia, the antCataglyphis bicolor, the flyLispe candicans, different carabids of the generaPogonus, Dichirotrichus, Dyschirius, Bembidion andCalathus and the wading birdsHaematopus ostralegus andCalidris alba. The secretion of the abdominal glands contains the toxin ptoluquinone dissolved in either-dodecalactone and 1-undecene (B. furcatus andB. spectabilis) or in octanoic acid and octyloctanoate (B. arenarius). The ratio of these solvents is species-specific. Application experiments using some of the natural insect predators (L. riparia, C. bicolor, Pogonus, Di. gustavii, Dyschirius) revealed that these solvent ratios provided a more effective deterrent than other possible ratios. Thus by combining the solvents in certain ratios, the capability of cuticular penetration and therefore the effectiveness of the defensive secretions are adapted to their natural targets.     

Democracy versus development: New urban debates

The politics of development includes subtexts of choice, as underpinned by community consensus (or lack of it), against the larger backdrop of a liberal democracy, with its intricate power structures that influence the choice of concepts and often lead to complicity rather than consent. A dilemma exists between the understanding of field-level practitioners and that of academics, whose understandings of progress differ. Progress can (and often does) imply long-term change across generations whereas development is often more a matter of crisis management and delivering tangible results to end-users. This makes it a bone of contention across political systems, irrespective of local or global dynamics. Development can emerge as a tool to be wielded for power and further political mileage at the expense of progress. Progress cannot be studied as a counterpoint to development as the sense of history is often missing in development interventions. Development tends to be piecemeal as its very logic often stems from the rationale of power. This is not to suggest, however, that development is only about politics; it is definitely more than the politics of everyday life and involves all of civil society that requires its critical and immediate attention. In this sense, it has become a priority for politicians with an underlying agenda designed to out-manouevre dissent and all statements of protest.     

A framework to measure the wildness of managed large vertebrate populations

As landscapes continue to fall under human influence through habitat loss and fragmentation, fencing is increasingly being used to mitigate anthropogenic threats and enhance the commercial value of wildlife. Subsequent intensification of management potentially erodes wildness by disembodying populations from landscape-level processes, thereby disconnecting species from natural selection. Tools are needed to measure the degree to which populations of large vertebrate species in formally protected and privately owned wildlife areas are self-sustaining and free to adapt. We devised a framework to measure such wildness based on 6 attributes relating to the evolutionary and ecological dynamics of vertebrates (space, disease and parasite resistance, exposure to predation, exposure to limitations and fluctuations of food and water supply, and reproduction). For each attribute, we set empirical, species-specific thresholds between 5 wildness states based on quantifiable management interventions. We analysed data from 205 private wildlife properties with management objectives spanning ecotourism to consumptive utilization to test the framework on 6 herbivore species representing a range of conservation statuses and commercial values. Wildness scores among species differed significantly, and the proportion of populations identified as wild ranged from 12% to 84%, which indicates the tool detected site-scale differences both among populations of different species and populations of the same species under different management regimes. By quantifying wildness, this framework provides practitioners with standardized measurement units that link biodiversity with the sustainable use of wildlife. Applications include informing species management plans at local scales; standardizing the inclusion of managed populations in red-list assessments; and providing a platform for certification and regulation of wildlife-based economies. Applying this framework may help embed wildness as a normative value in policy and mitigate the shifting baseline of what it means to truly conserve a species.     

Achieving Open Access to Conservation Science

Conservation science is a crisis discipline in which the results of scientific enquiry must be made available quickly to those implementing management. We assessed the extent to which scientific research published since the year 2000 in 20 conservation science journals is publicly available. Of the 19,207 papers published, 1,667 (8.68%) are freely downloadable from an official repository. Moreover, only 938 papers (4.88%) meet the standard definition of open access in which material can be freely reused providing attribution to the authors is given. This compares poorly with a comparable set of 20 evolutionary biology journals, where 31.93% of papers are freely downloadable and 7.49% are open access. Seventeen of the 20 conservation journals offer an open access option, but fewer than 5% of the papers are available through open access. The cost of accessing the full body of conservation science runs into tens of thousands of dollars per year for institutional subscribers, and many conservation practitioners cannot access pay‐per‐view science through their workplace. However, important initiatives such as Research4Life are making science available to organizations in developing countries. We urge authors of conservation science to pay for open access on a per‐article basis or to choose publication in open access journals, taking care to ensure the license allows reuse for any purpose providing attribution is given. Currently, it would cost $51 million to make all conservation science published since 2000 freely available by paying the open access fees currently levied to authors. Publishers of conservation journals might consider more cost effective models for open access and conservation‐oriented organizations running journals could consider a broader range of options for open access to nonmembers such as sponsorship of open access via membership fees. Obtención de Acceso Abierto a la Ciencia de la Conservación     

Sexual Predators,Energy Development,and Conservation in Greater Yellowstone

Abstract: In the United States, as elsewhere, a growing debate pits national energy policy and homeland security against biological conservation. In rural communities the extraction of fossil fuels is often encouraged because of the employment opportunities it offers, although the concomitant itinerant workforce is often associated with increased wildlife poaching. We explored possible positive and negative factors associated with energy extraction in the Greater Yellowstone Ecosystem (GYE), an area known for its national parks, intact biological diversity, and some of the New World's longest terrestrial migrations. Specifically, we asked whether counties with different economies—recreation (ski), agrarian (ranching or farming), and energy extractive (petroleum)—differed in healthcare (gauged by the abundance of hospital beds) and in the frequency of sexual predators. The absolute and relative frequency of registered sex offenders grew approximately two to three times faster in areas reliant on energy extraction. Healthcare among counties did not differ. The strong conflation of community dishevel, as reflected by in‐migrant sexual predators, and ecological decay in Greater Yellowstone is consistent with patterns seen in similar systems from Ecuador to northern Canada, where social and environmental disarray exist around energy boomtowns. In our case, that groups (albeit with different aims) mobilized campaigns to help maintain the quality of rural livelihoods by protecting open space is a positive sign that conservation can matter, especially in the face of rampant and poorly executed energy extraction projects. Our findings further suggest that the public and industry need stronger regulatory action to instill greater vigilance when and where social factors and land conversion impact biological systems.     

Comparison of the insecticidal effects of water extracted and intact aromatic plants onAcanthoscelides obtectus,a bruchid beetle pest of kidney beans

Summary Acanthoscelides obtectus (Say) is one of the most damaging pests of kidney beans,Phaseolus vulgaris L. worldwide. However, aromatic plants from the families Lamiaceae, Lauraceae, Myrtaceae and Poaceae can protect kidney beans by direct or delayed insecticidal effect, through increased adult mortality and inhibition of beetle reproduction (both oviposition and adult emergence). The efficiency of hydrodistillated and intact plants fromThymus vulgaris andT. serpyllum, Mentha piperata, Rosmarinus officinalis, Satureia hortensis, Eucalyptus globulus, Laurus nobilis, Origanum vulgare, andCymbopogon nardus was compared. For both extracts,Origanum vulgare had the best effect. The insecticidal effect was induced by more than the essential oils because no significant difference was noticed between distilled and intact plants extract. Inhibition of reproduction was particularly important. These results suggest that lipidic as well as non lipidic, allelochemicals, such as phenolics, or non-protein amino-acids, or flavonoids may be involved in the toxicity of aromatic plants to this beetle.     

Rapid,recurring, structured survey versus bioblitz for generating biodiversity data and analysis with a multispecies abundance model

A bioblitz inexpensively and quickly generates biodiversity data, but bioblitzes are often conducted with haphazard, unreplicated sampling. Results tend to be taxonomically, geographically, or temporally biased, lack metadata, and consist of lists of observed taxa that do not enable further analyses or correction for imperfect detection. A rapid, recurring, structured survey (RRSS) uses a structured sampling design and temporal and spatial replication to survey randomly selected sites on a conservation property. We participated in a loosely structured bioblitz and a subsequent RRSS at Big Canoe Creek Nature Preserve in Springville (St. Clair County), Alabama (USA) to compare observed richness derived from the 2 survey approaches. The RRSS data structure enabled us to fit models that accounted for imperfect detection to estimate abundances, occupancy probabilities, and habitat associations. The loosely structured bioblitz data could not be used in such models. We present a new integrated multispecies abundance model that we applied to avian RRSS data. Our model extension enables estimation for the community, employs data augmentation to estimate the number of undetected species, and incorporates covariates. The RRSS generated a more comprehensive and less biased list of observed taxonomic richness than the loosely structured bioblitz (e.g., 73 vs. 45 bird species and 104 vs. 63 insect families from the RRSS vs. loosely structured bioblitz, respectively). Models fit to the RRSS data identified seasonal patterns in avian community composition and allowed for estimation of habitat–occupancy relationships for insect taxa. The RRSS protocol has potential for broad transferability as a standardized, quick, and inexpensive way to inventory biodiversity and estimate ecological parameters while providing an outreach opportunity.     

Compliance with and ecosystem function of biodiversity offsets in North American and European freshwaters

Land-use change via human development is a major driver of biodiversity loss. To reduce these impacts, billions of dollars are spent on biodiversity offsets. However, studies evaluating offset project effectiveness that examine components such as the overall compliance and function of projects remain rare. We reviewed 577 offsetting projects in freshwater ecosystems that included the metrics project size, type of aquatic system (e.g., wetland and creek), offsetting measure (e.g., enhancement, restoration, and creation), and an assessment of the projects’ compliance and functional success. Project information was obtained from scientific and government databases and gray literature. Despite considerable investment in offsetting projects, crucial problems persisted. Although compliance and function were related to each other, a high level of compliance did not guarantee a high degree of function. However, large projects relative to area had better function than small projects. Function improved when projects targeted productivity or specific ecosystem features and when multiple complementary management targets were in place. Restorative measures were more likely to achieve targets than creating entirely new ecosystems. Altogether the relationships we found highlight specific ecological processes that may help improve offsetting outcomes.     

Some polyphagous Homoptera gain protection from their natural enemies by feeding on the toxic plantsSpartium junceum andErythrina corallodendrum (Leguminosae)

Summary Interactions were studied among alkaloid-containing legumes (Erythrina corallodendrum andSpartium junceum) and non-toxic plants (Citrus sinensis, Cucurbita moschata andEuphorbia tirucalli), several polyphagous homopterans,Aphis craccivora (Aphididae),Icerya purchasi, I. aegyptiaca (Margarodidae),Lepidosaphes ulmi (Diaspididae) andPlanococcus citri (Pseudococcidae), and some major natural enemies of these homopterans. Significant reductions in survival due to negative effects of alkaloid containing as compared with non-alkaloidal plants were recorded for the predatorsRodolia cardinalis andChilocorus bipustulatus, but not forCryptolaemus montrouzieri (Coleoptera: Coccinellidae),Chrysoperla carnea (Neuroptera: Chrysopidae) andSympherobius sanctus (Neuroptera: Sympherobiidae). The development time of the larvae or pupae ofR. cardinalis, C. carnea andS. sanctus was longer on the toxic plants than on the non-toxic ones. The percentage of parasitism ofA. craccivora collected from the non-alkaloidal plantsVicia palaestina andMelilotus albus was much higher than that onS. junceum. The parasitoid complexes ofA. craccivora differed between both plant groups. The nutritive value of honeydew ofI. purchasi andA. craccivora, as expressed by the life span ofEncyrtus infelix (Hymenoptera: Encyrtidae) adults, was also investigated. Life spans were significantly longer when the wasps fed on honeydew produced on non-alkaloidal plants (C. sinensis andPittosporum tobira) than on alkaloid containing plants whenI. purchasi — but notA. craccivora — was the producer. It is suggested that the chemical defense ofE. corallodendrum andS. junceum is exploited by polyphagous phytophages to reduce predation. In nature, population growth and density of four of the investigated homopterans are conspicuously high when they developed on the alkaloid containing plant species, and very low on non-alkaloid plants. The efficiency of their natural enemies may be reduced by sequestration of alkaloids (or other toxic plant compounds) or their transfer into excreted honeydew. Therefore it is assumed that a generalist phytophagous homopteran may be protected from its natural enemies, although at different rates of efficiency, if it can safely sequester the host allelochemical when it develops on toxic species within its host range.