CrylAb蛋白在拟环纹豹蛛体内的富集及对其体内酶活性的影响

用Cry1Ab蛋白处理的果蝇喂养拟环纹豹蛛Pardosa pseudoannulata,在第1d、3d、5d、7d、9d、11d用酶联免疫(ELISA)检测技术测定实验组和对照组拟环纹豹蛛体内Cry1Ab蛋白含量,运用紫外分光光度法检测拟环纹豹蛛体内超氧化物歧化酶( SOD)、谷胱甘肽过氧化物酶(GSH-Px)、乙酰胆碱酯酶(AChE)的活性,探讨拟环纹豹蛛体内Cry1Ab蛋白的富集作用与其体内3种酶活性的关系.结果表明,从第1d至第7 d Cry1Ab蛋白在拟环纹豹蛛体内均具富集作用(p＜0 05),到第7d的时候达到最高值,达极显著差异(p＜0.01),然后逐渐降低,但仍显著高于对照(p＜0.05).SOD酶活性总体趋势是降低的,在第7d达到最低;用Cry1Ab蛋白处理拟环纹豹蛛后其体内的AChE和GSH-Px酶活性随饲养时间的延长而增加,并均高于对照组(p＜0.05).该研究证明Cry1Ab蛋白在拟环纹豹蛛体内具有富集效应,并且其体内Cry1Ab蛋白对其体内GSH-Px、AChE具有一定诱导作用,对SOD酶具有一定程度的抑制作用.     

Cry1Ab蛋白在拟环纹豹蛛体内的富集及对其体内酶活性的影响

用Cry1Ab蛋白处理的果蝇喂养拟环纹豹蛛Pardosa pseudoannulata,在第1d、3d、5d、7d、9d、11d用酶联免疫（ELISA）检测技术测定实验组和对照组拟环纹豹蛛体内Cry1Ab蛋白含量,运用紫外分光光度法检测拟环纹豹蛛体内超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH—Px）、乙酰胆碱酯酶（AChE）的活性,探讨拟环纹豹蛛体内Cw1Ab蛋白的富集作用与其体内3种酶活性的关系。结果表明,从第ld至第7dC~IAb蛋F1在拟环纹豹蛛体内均具富集作用（P〈0．05）,到第7d的时候达到最高值,达极显著差异（p〈0．01）,然后逐渐降低,但仍显著高于对照（p〈0．05）。SOD酶活性总体趋势是降低的,在第7d达到最低;用Cry1Ab蛋白处理拟环纹豹蛛后其体内的AChE和GSH—Px酶活性随饲养时间的延长而增加,并均高于对照组（p〈0．05）。该研究征明Cry1Ab蛋白在拟环纹豹蛛体内具有富集效应,并且其体内Cry1Ab蛋白对其体内GSH—Px、AChE具铂一定诱导作用,对SOD酶具有一定程度的抑制作用。     

5种杀虫剂对西花蓟马和花蓟马的毒力及其生理酶活性的影响

【目的】探究不同杀虫剂对重要入侵害虫西花蓟马及其本地近缘种花蓟马的毒力及对保护酶和解毒酶活性的影响,为进一步研究2种害虫的抗性管理提供依据。【方法】采用浸渍法测定5种田间常用杀虫剂对西花蓟马和花蓟马的毒力,并测定杀虫剂亚致死浓度(LC25)下2种蓟马体内保护酶和解毒酶活性的差异。【结果】不同杀虫剂对2种蓟马的毒力依次为:乙基多杀菌素甲维盐阿维菌素吡虫啉噻虫嗪,乙基多杀菌素对西花蓟马和花蓟马的LC_(50)分别为0.28和0.03 mg·L~(-1)。不同药剂的亚致死剂量(LC_(25))对西花蓟马和花蓟马体内保护酶和解毒酶活性普遍具有诱导作用。其中,阿维菌素对西花蓟马超氧化物歧化酶(SOD)活性诱导作用最强,为326.40 U·mg~(-1),是对照的9.37倍,而乙基多杀菌素对花蓟马SOD活性诱导作用最强,为245.35 U·mg~(-1),是对照的9.32倍;吡虫啉对西花蓟马和花蓟马过氧化物酶(POD)诱导作用最强,分别为298.67和246.79 U·mg~(-1),是对照的37.10和20.57倍;阿维菌素对西花蓟马和花蓟马过氧化氢酶(CAT)和羧酸酯酶(CarE)诱导作用最强,分别为298.67、246.79 U·mg~(-1)(CAT活性)和12.53、11.99 U·mg~(-1)(CarE活性);乙基多杀菌素对西花蓟马和花蓟马谷胱甘肽转移酶(GST)和乙酰胆碱酯酶(AChE)诱导作用最强,分别为77527.59、66927.39 U·mg~(-1)(GST活性)和2.34、2.22 U·mg~(-1)(AChE活性)。【结论】5种杀虫剂中,乙基多杀菌素对2种蓟马的毒力最强;西花蓟马对杀虫剂的解毒代谢能力强于花蓟马。     

甲胺磷对拟环纹豹蛛中肠蛋白消化酶活性影响的压电传感监测（英文）

利用压电体声波阻抗分析法实时动态监测了拟环纹豹蛛Pardosa pseudoannulata中肠蛋白消化酶对酪蛋白的酶促水解过程及不同浓度梯度（0.008%、0.016%、0.024%和0.032%）的甲胺磷农药对酶活性的影响,并用紫外分光光度法进行了验证。结果表明,合适低剂量(0.008%)的甲胺磷农药可显著地增强拟环纹豹蛛蛋白消化酶的活性,较高剂量(0.032%)的农药却显著抑制蛋白消化酶的活性,且水解过程稳态频移值可准确地反映酶活性与农药浓度的关系。本工作为研究低剂量农药增强蜘蛛控虫力的机理及酶活性的快速检测提供了一种可行的新方法。     

四种类型杀虫剂对麦长管蚜的温度效应及其与主要解毒酶的关系

为了明确杀虫剂毒力受温度的影响及其程度,本文测定了4大类8种药剂在10～25℃下对麦长管蚜的毒力;并测定了麦长管蚜Sitobion avenae(Fabricius)在不同温度下2个解毒酶和1个靶标酶的活性差异。结果表明,高效氯氰菊酯对麦长管蚜表现不规则负温度系数,啶虫脒表现不规则正温度系数,高效氟氯氰菊酯对麦长管蚜的毒力不受温度影响,其他药剂(辛硫磷、毒死蜱、灭多威、丁硫克百威、吡虫啉)均表现为明显的正温度系数效应,以有机磷类杀虫剂表现最为明显,毒死蜱温度系数高达57.70。酶活性实验表明:麦长管蚜在高温下GST活性增强,羧酸酯酶和乙酰胆碱酯酶活性降低。它们的变化规律表明:GST活性与负温度系数密切相关,正温度系数与羧酸酯酶活性和靶标酶乙酰胆碱酯酶活性有关。     

不同生境汞对拟水狼蛛抗氧化系统的影响

以拟水狼蛛为研究对象,采用原子吸收光谱法测定了不同生境汞在土壤和蜘蛛体内的含量,研究了不同生境汞对拟水狼蛛抗氧化酶的影响.结果 表明:4个采集样点(S1、S2、S3和S4)拟水狼蛛体内重金属汞的含量差异显著(P<0.05).在重金属胁迫下,重金属汞含量高(S1、S2和S3)的拟水狼蛛体内GSH含量显著高于对照组(S4),是对照组的2.4~3.8倍.GSH含量与重金属汞含量显著正相关(r2=0.9624,P<0.01).对于GST、CAT和SOD,重金属汞含量高则酶活性低,GST、CAT和SOD酶活性与重金属汞含量显著负相关.因此检测拟水狼蛛体内的酶活性变化即可知环境中重金属汞的污染程度,提示拟水狼蛛可以作为重金属污染的重要监测指示生物.     

杀虫剂啶虫脒和毒死蜱对捕食蜘蛛血细胞DNA的损伤作用

应用蜘蛛血细胞微核试验和单细胞凝胶电泳试验研究了两种杀虫剂啶虫脒和毒死蜱对蜘蛛头胸部和腹部血细胞DNA的损伤作用。结果表明：在啶虫脒和毒死蜱各供试浓度作用下,对蜘蛛血细胞微核率有明显的影响,与对照组相比有显著性差异(p<0.05,p<0.01);且随着两种农药浓度升高,血细胞微核率显著增加,存在明显的剂量-效应关系(啶虫脒浓度与星豹蛛头胸部血细胞微核率相关系数r=0.9284,腹部为r=0.9071;毒死蜱与星豹蛛头胸部血细胞微核率相关系数r=0.9841,腹部为r=0.9793);啶虫脒和毒死蜱对星豹蛛血细胞DNA损伤有明显的剂量-效应关系(啶虫脒浓度与星豹蛛头胸部血细胞DNA损伤相关系数r=0.9838,腹部为r=0.9834;毒死蜱与星豹蛛头胸部血细胞DNA损伤相关系数r=0.9807,腹部为r=0.9659);且两种农药在同种农药同一浓度作用下,对星豹蛛腹部血细胞微核率和DNA损伤程度要明显大于头胸部。     

辣椒素对西花蓟马雌成虫体内解毒酶活性的影响

【目的】为明确非挥发性次生物质辣椒素对西花蓟马Frankliniella occidentalis雌成虫体内解毒酶活性的影响。【方法】将菜豆叶片研碎离心后取上清液作为西花蓟马的液态饲料,将不同浓度的辣椒素添加到饲料中,饲养西花蓟马雌成虫48、72、96 h后,分别测定西花蓟马体内羧酸酯酶(Car E)、谷胱甘肽-S-转移酶(GSTs)、乙酰胆碱酯酶(AChE)和多功能氧化酶(MFO)的活性。【结果】低剂量辣椒素能诱导西花蓟马雌成虫体内GSTs、AChE和MFO活性明显升高,高剂量辣椒素抑制GSTs、AChE及MFO活性。不论在哪一种辣椒素浓度下,Car E活性一直受到抑制。辣椒素浓度和处理时间对GSTs及AChE活性无明显交互作用,但对Car E及MFO有明显的交互作用,处理时间越长,作用越显著。【结论】西花蓟马雌成虫体内解毒酶活性在次生物质辣椒素处理下发生了明显的变化,说明西花蓟马通过解毒酶适应次生物质对其的影响,但解毒酶的变化有剂量和时间效应。     

草间小黑蛛对茶蚜的捕食功能反应

在实验室条件下研究了草间小黑蛛(Erigonidium graminicolum)对茶蚜(Toxoptera aurantii)的捕食作用。草间小黑蛛对茶蚜的捕食功能反应属于HollingⅡ型。草间小黑蛛有较强的种内干扰反应,随着捕食者密度的增大,草间小黑蛛的捕食率相应降低。猎物密度和天敌密度相互干扰会降低草间小黑蛛的寻找效应,但对捕食量没有影响。     

低剂量农药作用下拟环纹豹蛛对褐飞虱的功能反应及搜寻行为

在室内研究了低剂量农药作用下拟环纹豹蛛对褐飞虱的功能反应及搜寻行为。结果表明,拟环纹豹蛛对褐飞虱的功能反应均符合Holling Ⅱ模型,且在最适的低剂量农药(V_药∶V_水为2∶5 000甲胺磷,12∶5 000杀虫双和1∶20烯丙菊酯)刺激下,蜘蛛捕食褐飞虱的数量是最多的,蜘蛛用于对1头褐飞虱进行制服和取食等活动所需的时间（处理猎物时间,Th）短,仅分别为未经农药处理的蜘蛛所需时间的0.45、0.32和0.35倍;而施用较高剂量8∶5 000的甲胺磷、28∶5 000的杀虫双和6∶20的烯丙菊酯的蜘蛛,处理猎物时间长得多,依次是经最适低剂量3种农药作用的蜘蛛所用时间的9.70、13.60和13.62倍。拟环纹豹蛛在稻株上的搜寻行为属非随机搜索型,在相同的低剂量农药作用下,蜘蛛的搜寻效应随飞虱密度的增加而下降;但在相同的猎物密度下,蜘蛛的搜寻效应与使用的农药浓度有密切的关系,在上述最适低剂量农药作用下,豹蛛对猎物的寻找效应最佳,其在稻株上的总滞留时间依次是未施药情形的1.56、1.49、1.48倍,总搜寻距离依次是未施药情形的1.36、1.42、1.39倍。据此,进一步证实了低剂量农药增强了稻田蜘蛛的控虫效能和对害虫的相对活力。     

Comparative Growth and Development of Spiders Reared on Live and Dead Prey

Scavenging (feeding on dead prey) has been demonstrated across a number of spider families, yet the implications of feeding on dead prey for the growth and development of individuals and population is unknown. In this study we compare the growth, development, and predatory activity of two species of spiders that were fed on live and dead prey. Pardosa astrigera (Lycosidae) and Hylyphantes graminicola (Lyniphiidae) were fed live or dead fruit flies, Drosophila melanogaster. The survival of P. astrigera and H. graminicola was not affected by prey type. The duration of late instars of P. astrigera fed dead prey were longer and mature spiders had less protein content than those fed live prey, whereas there were no differences in the rate of H. graminicola development, but the mass of mature spiders fed dead prey was greater than those fed live prey. Predation rates by P. astrigera did not differ between the two prey types, but H. graminicola had a higher rate of predation on dead than alive prey, presumably because the dead flies were easier to catch and handle. Overall, the growth, development and reproduction of H. graminicola reared with dead flies was better than those reared on live flies, yet for the larger P. astrigera, dead prey may suit smaller instars but mature spiders may be best maintained with live prey. We have clearly demonstrated that dead prey may be suitable for rearing spiders, although the success of the spiders fed such prey appears size- and species specific.     

Antioxidative responses in females and males of the spider Xerolycosa nemoralis (Lycosidae) exposed to natural and anthropogenic stressors

The aim of this study was to assess the intensity of enzymatic antioxidative parameters [i.e., superoxide dismutase (SOD), catalase (CAT), and the glutathione peroxidases each selene dependent, GPOX or selene independent, including GSTPx, glutathione S-transferase, and GST] and non-enzymatic antioxidative parameters [i.e., glutathione total (GSH-t), the heat shock proteins of Hsp70, and metallothioneins (Mt)] in the midgut glands of female and male wolf spiders Xerolycosa nemoralis (Lycosidae) exposed to natural stressors (i.e., heat shock and starvation) and anthropogenic stressors (i.e., the organophosphorous pesticide dimethoate) under laboratory conditions. The spiders were collected from two differentially polluted sites both localized in southern Poland: Olkusz, which is heavily polluted with metals, and Pilica, the reference site. In response to the stressing factors, increases in Hsp70 levels, in the concentrations of total glutathione and in the activity levels of glutathione-dependent enzymes (GPOX, GSTPx, and GST) were found in the midgut glands of males. In the females, high levels of activity of CAT and SOD were revealed, as well as an increased percentage of Mt-positive cells. Preexposed females, in comparison to the individuals from the reference site, responded with increased SOD activity, irrespective of the stressing factor. In contrast, the changes in the antioxidative parameters in the midgut glands of male X. nemoralis seem to reflect a short-term reaction to the applied stressors and do not confirm the effects of long-term selection in a polluted environment.     

Stage-Specific Behavioral Responses of Ageneotettix deorum (Orthoptera: Acrididae) in the Presence of Lycosid Spider Predators

Grasshoppers must gather food while avoiding size-selective predation from other arthropods, especially spiders, potentially leading to a trade-off between foraging and defensive behaviors. This trade-off becomes less intense as prey grow larger and are less susceptible to arthropod predation. Activity budgets were constructed for three nymphal (third- to fifth- instar) and adult life cycle stages of Ageneotettix deorum, a common rangeland grasshopper, for three conditions of predation risk by lycosid spiders (spider absence, spider presence, and presence of a nonlethal, chelicerae-modified spider). In third and fourth instars, exposure to predators resulted in reduced feeding activity, increased time spent in antipredator and defensive behaviors, and reduced general activity compared to individuals not exposed to spiders. No significant shifts in behaviors were observed for fifth-instar nymphs and adult A. deorum in response to spider presence. Activity levels in functional spiders and chelicerae-modified spiders were statistically indistinguishable.     

Transgenic Cabbage Expressing Cry1Ac1 Does Not Affect the Survival and Growth of the Wolf Spider,Pardosa astrigera L. Koch (Araneae: Lycosidae)

Both herbivores that consume transgenic crops and their predators can be exposed to insecticidal proteins expressed in those crops. We conducted a tritrophic bioassay to evaluate the ecotoxicological impacts that Bt cabbage (Brassica oleracea var. capitata) expressing Cry1Ac1 protein might have on the wolf spider (Pardosa astrigera), a non-target generalist predator. Enzyme-Linked Immunosorbent Assays indicated that protein levels were 4.61 ng g^-1 dry weight in fruit flies (Drosophila melanogaster) fed with the transgenic cabbage and 1.86 ng g^-1 dry weight in the wolf spiders that preyed upon them. We also compared the life history traits of spiders collected from Bt versus non-Bt cabbage and found no significant differences in their growth, survival, and developmental rates. Because Bt cabbage did not affect the growth of fruit flies, we conclude that any indirect effects that this crop had on the wolf spider were probably not mediated by prey quality. Therefore, exposure to Cry1Ac1 protein when feeding upon prey containing that substance from transgenic cabbage has only a negligible influence on those non-target predatory spiders.     

Neonicotinoid insecticide imidacloprid causes outbreaks of spider mites on elm trees in urban landscapes

Background

Attempts to eradicate alien arthropods often require pesticide applications. An effort to remove an alien beetle from Central Park in New York City, USA, resulted in widespread treatments of trees with the neonicotinoid insecticide imidacloprid. Imidacloprid''s systemic activity and mode of entry via roots or trunk injections reduce risk of environmental contamination and limit exposure of non-target organisms to pesticide residues. However, unexpected outbreaks of a formerly innocuous herbivore, Tetranychus schoenei (Acari: Tetranychidae), followed imidacloprid applications to elms in Central Park. This undesirable outcome necessitated an assessment of imidacloprid''s impact on communities of arthropods, its effects on predators, and enhancement of the performance of T. schoenei.

Methodology/Principal Findings

By sampling arthropods in elm canopies over three years in two locations, we document changes in the structure of communities following applications of imidacloprid. Differences in community structure were mostly attributable to increases in the abundance of T. schoenei on elms treated with imidacloprid. In laboratory experiments, predators of T. schoenei were poisoned through ingestion of prey exposed to imidacloprid. Imidacloprid''s proclivity to elevate fecundity of T. schoenei also contributed to their elevated densities on treated elms.

Conclusions/Significance

This is the first study to report the effects of pesticide applications on the arthropod communities in urban landscapes and demonstrate that imidacloprid increases spider mite fecundity through a plant-mediated mechanism. Laboratory experiments provide evidence that imidacloprid debilitates insect predators of spider mites suggesting that relaxation of top-down regulation combined with enhanced reproduction promoted a non-target herbivore to pest status. With global commerce accelerating the incidence of arthropod invasions, prophylactic applications of pesticides play a major role in eradication attempts. Widespread use of neonicotinoid insecticides, however, can disrupt ecosystems tipping the ecological balance in favor of herbivores and creating pest outbreaks.     

Spider predation on a mirid pest in Japanese rice fields

Spiders are common generalist predators, and understanding their potential in biological control is important for the development of integrated pest management programs. In this study, predation by three groups of spiders on the mirid bug Stenotus rubrovittatus (Hemiptera: Miridae) in rice paddies was investigated using DNA-based gut-content analysis. A laboratory feeding study revealed that the detection half-lives of bug DNA in the spider gut at 25 °C was 3.4 days for Lycosidae and 1.5 days for Tetragnathidae. Individual spider predation on the mirid bug was investigated by detecting DNA of prey in field-collected spiders. In total, 1199 spiders were assayed from three spider groups: Pirata subpiraticus (Lycosidae), Tetragnatha spp. (Tetra-gnathidae), and Pachygnatha clercki (Tetra-gnathidae), which each differ in their preferred microhabitat as well as their predatory habits. Detection rates of prey DNA in spiders increased significantly with the density of prey across all spider groups. P. subpiraticus and Tetragnatha spp. predation showed a better fit to a saturated response curve to increasing prey density, while P. clercki showed a simple linear relationship with prey density. Densities of alternative prey species did not affect the detection rates of mirids. These results suggest that predation on pests by generalist predators in an agroecosystem is affected not only by prey abundance but also by predator preference for specific prey. Predator preference is therefore an important factor to consider when estimating the role of natural enemies as biological control agents.     

The lethal and sublethal effects of three pesticides on the striped lynx spider (Oxyopes salticus Hentz)

The striped lynx spider, Oxyopes salticus Hentz, is found in high abundances in agricultural fields where it forages on many agricultural pests. Pesticides are applied to these fields and can therefore impact these natural pest predators. Researchers have examined the effects of a number of pesticides on this spider and other pest predators, but many of these studies only examine how these pesticides affect mortality. More recently, researchers have begun to examine the sublethal effects of these chemicals. We examined both the lethal and sublethal effects of three common pesticides with the active ingredients bifenthrin, carbaryl and malathion. We found that only malathion significantly reduced the post‐exposure lifespan of these spiders; however, each pesticide had sublethal effects on behaviour. Exposure to malathion reduced jumping, likely an important foraging and escape behaviour. Spiders exposed to bifenthrin spent increased time grooming, which can reduce the time spent performing other important behaviours. Finally, spiders that were exposed to carbaryl surprisingly increased their prey capture rate. We show here that pesticides can not only directly affect the lifespan of the striped lynx spider but that each pesticide can cause different sublethal effects that likely impact the survival and ecology of these important pest predators.     

Body size and tree species composition determine variation in prey consumption in a forest‐inhabiting generalist predator

Trophic interactions may strongly depend on body size and environmental variation, but this prediction has been seldom tested in nature. Many spiders are generalist predators that use webs to intercept flying prey. The size and mesh of orb webs increases with spider size, allowing a more efficient predation on larger prey. We studied to this extent the orb‐weaving spider Araneus diadematus inhabiting forest fragments differing in edge distance, tree diversity, and tree species. These environmental variables are known to correlate with insect composition, richness, and abundance. We anticipated these forest characteristics to be a principle driver of prey consumption. We additionally hypothesized them to impact spider size at maturity and expect shifts toward larger prey size distributions in larger individuals independently from the environmental context. We quantified spider diet by means of metabarcoding of nearly 1,000 A. diadematus from a total of 53 forest plots. This approach allowed a massive screening of consumption dynamics in nature, though at the cost of identifying the exact prey identity, as well as their abundance and putative intraspecific variation. Our study confirmed A. diadematus as a generalist predator, with more than 300 prey ZOTUs detected in total. At the individual level, we found large spiders to consume fewer different species, but adding larger species to their diet. Tree species composition affected both prey species richness and size in the spider''s diet, although tree diversity per se had no influence on the consumed prey. Edges had an indirect effect on the spider diet as spiders closer to the forest edge were larger and therefore consumed larger prey. We conclude that both intraspecific size variation and tree species composition shape the consumed prey of this generalist predator.