茭白田蜘蛛的群落结构及多样性调查

对茭白田中的蜘蛛Spider群落进行了系统的采样调查,对茭白田和蔬菜地、蚕豆地、小麦地、冬闲田、田埂和荒地等生境中的越冬蜘蛛的群落结构和多样性进行了比较,并就茭白田对邻近稻田蛛量的影响进行了初步研究.结果表明,茭白田越冬蜘蛛种类有11科、31属、48种.在茭白田中越冬的蜘蛛密度是其它生境的4倍～40倍.拟水狼蛛Piratasubpiraticus是茭白田蜘蛛的优势种,占总数的50%以上.茭白田可提高邻近稻田蛛量约30%.茭白田是蜘蛛尤其是拟水狼蛛在稻田生态系统主要的越冬场所和避难所,对保护稻田蜘蛛起到重要的作用.     

用ELISA方法研究稻田节肢动物的食物关系

应用酶联免疫吸附试验双抗体夹心法,研究了稻田节肢动物,包括19种捕食性天敌、4种主要水稻害虫及1种中性昆虫之间的食物关系。在检测的19种捕食者中,有15种捕食了白背飞虱,11种捕食了褐飞虱。其中食虫沟瘤蛛、拟水狼蛛、八斑鞘蛛、粽管巢蛛、四斑锯螯蛛和拟环纹豹蛛对两种稻飞虱的捕食阳性率较高。有7种捕食了稻纵卷叶螟幼虫,其中粽管巢蛛、褶管巢蛛、拟环纹豹蛛、青翅蚁形隐翅虫和印度细颈步甲的捕食阳性率较高。拟环纹豹蛛、浙江豹蛛和拟水狼蛛对稻蝗若虫有较高的阳性率。13种捕食者捕食了摇蚊,摇蚊作为替代或补充猎物,对稻田捕食性节肢动物亚群落的重建和发展具有重要意义。在实验检测的基础上,构建了被检测节肢动物猎物与捕食者间的食物关系图。     

稻田水狼蛛空间分布型研究初报

稻田水狼蛛占蜘蛛总量的18.1—52.8％,平均达35.8％,主要种类有拟水狼蛛(Pirata subpiraticus)、弓水狼蛛(P.procurvus),它们均栖息于稻丛基数,捕食稻飞虱、叶蝉为主,捕食量大,是稻田害虫最主要捕食性天敌类型,对开展综合防治有一定的意义。为此我们于1986年6—9月正值早稻抽穗灌浆期,在松阳县大东坝稻田对水狼蛛作了调查,并统计判别其空间分布类型,并按Iwao的抽样公式对其抽样数量进行探讨。     

水稻-白背飞虱-拟水狼蛛食物链中生物量流动的定量研究

采用荧光物质示踪技术对早稻稻田生态系统中的水稻-白背飞虱拟水狼蛛食物链在抽穗期与乳熟期中营养物质流动进行了定量测定。结果表明: 在所施荧光示踪物质3种质量浓度20、50、100 mg/L中,水稻、白背飞虱、拟水狼蛛的荧光物含量［μg/鲜重(g)］随所施荧光物浓度的增加而增加,浓度组间差异达到显著水平,呈现出较为稳定的规律性。早稻抽穗期每头白背飞虱每24 h取食水稻0.0636 g,平均每头拟水狼蛛每24 h捕食白背飞虱0.0336 g,约6～7头;在早稻乳熟期每头白背飞虱每24 h取食水稻0.0155 g,平均每头拟水狼蛛每24 h捕食白背飞虱0.0416 g,约16头。结合田间调查数据分析,抽穗期白背飞虱危害低于乳熟期,差异显著;两个水稻生育期3～4龄拟水狼蛛的控虫力差异显著,乳熟期高于抽穗期。     

用ELISA方法评价捕食性天敌对白背飞虱的捕食效能

用酶联免疫吸附试验（ELISA）方法测定了9类捕食性节肢动物对白背飞虱的捕食阳性反应率,定量评价了拟水狼蛛对白背飞虱的捕食效能。结果表明：活动能力强,与稻飞虱生境相似的捕食性天敌种类表现出较高的阳性反应率;拟水狼蛛对白背飞虱的捕食效率随水稻的生长而加强,在水稻生长后期,分别为21.53％和43．08％。     

田埂留草控制稻飞虱效果及对捕食性天敌多样性影响

为探讨稻田田埂保留杂草控制稻飞虱的效果及对捕食性天敌多样性的影响,以稻田田埂周年性保留杂草为处理,以稻田田埂不保留杂草为对照,对处理区和对照区稻田稻飞虱成若虫、捕食性天敌种类和数量进行系统调查和分析。结果表明,在调查期内(6—10月),田埂留草稻田百丛稻株稻飞虱数量为(891.11±133.12)头,较非留草稻田减少35.31%;田埂留草稻田捕食性天敌隶属5目23科35种,而田埂非留草稻田隶属5目21科33种;田埂非留草稻田捕食性天敌优势种为食虫沟瘤蛛Ummeliata insecticepsBoes.etStr.、拟水狼蛛Pirata subpiraticus Boes.etStr.和黑肩绿盲蝽Cyrtorrhinus livdipennis Reuter,而田埂留草后优势种为食虫沟瘤蛛U.insecticeps、草间小黑蛛Erigonidium graminicolum(Sundevall)、拟水狼蛛和拟环纹狼蛛Lycosa pseudoamulata(Bose.etStr.);田埂留草稻田捕食性天敌的个体数量、丰富度、多样性指数分别为(128.89±13.52)、(33.67±0.50)、(4.53±0.04)头/百丛,较田埂非留草稻田分别增加31.96%、25.73%、5.59%,而优势度指数和均匀性指数没有显著变化。研究结果为发展稻田景观多样化控害提供依据。     

Cry1Ab杀虫蛋白在水稻-褐飞虱-拟水狼蛛食物链中转移与富集

采用ELISA方法检测了2个转cry1Ab基因水稻（Bt水稻）品系KMD1和KMD2不同生育期叶鞘内Cry1Ab杀虫蛋白的含量及其通过褐飞虱和拟水狼蛛的转移和富集情况。结果表明,这2个品系中抽穗期和黄熟期叶鞘内Cry1Ab的含量均显著低于苗期、分蘖期和孕穗期,KMD1和KMD2中Cry1Ab杀虫蛋白可以通过食物链转移到Bt水稻非靶标害虫褐飞虱及其天敌拟水狼蛛体内。褐飞虱在KMD1或KMD2上取食2 d后,体内均含有Cry1Ab杀虫蛋白,但连续取食2、4、6、8和10 d后,其体内含量并未因取食时间的延长而呈现明显增加的趋势。当拟水狼蛛捕食以KMD1或KMD2为食的褐飞虱时,在捕食2、4、6、8和10 d后,其体内均可检测到Cry1Ab杀虫蛋白,其含量并未随捕食时间的延长而明显上升,但均显著高于相应时间褐飞虱体内的含量。可见,该蛋白可通过水稻转移至褐飞虱,再转移至拟水狼蛛,并存在明显的富集现象,而这种富集并不随蜘蛛捕食时间的延长而加强。拟水狼蛛捕食以KMD1或KMD2为食的褐飞虱时,其捕食量未受到显著影响,其中肠酶粗提物对Cry1Ab杀虫蛋白具有明显的降解作用。     

几种杀虫剂对拟水狼蛛捕食功能的影响。

研究了稻田常用杀虫剂杀虫双、甲胺磷、扑虱灵3种农药对稻田主要捕食性天敌拟水狼蛛Pirata subpiraticus 捕食褐飞虱Nilaparvata lugens 功能的影响。提出用功能减退率来综合评价农药对天敌的影响。结果表明24h杀虫双常用浓度540mg/L、810mg/L对狼蛛的杀伤力为12.63%、27.57%。功能减退率分别高达65.41%和81.3%;甲胺磷100mg/L24h对狼蛛的杀伤力和功能减退率分别为49.8%和68.56%。这2种药剂对狼蛛的作用机制不同,甲胺磷毒性大,狼蛛死亡率高,但对非致死狼蛛的捕食功能减退率比杀虫双处理略小,狼蛛的捕食功能恢复快于杀虫双处理。杀虫双处理的浓度越高,狼蛛的功能减退率越大、功能恢复越慢。扑虱灵对狼蛛的杀伤和功能减退均不大。2种药剂处理后狼蛛功能恢复到正常水平约需7d左右。田间试验表明频繁地使用甲胺磷削弱了天敌功能导致飞虱再猖獗。     

水稻-褐飞虱-拟水狼蛛食物链的定量研究

应用荧光物质稀土元素铕示踪法对水稻褐飞虱拟水狼蛛食物链进行了定量分析研究。所施荧光物质的三种浓度20 mg/L、50 mg/L和100 mg/L 均为有效浓度,对水稻生长无可见的影响,孕穗期、抽穗期、乳熟期和黄熟期四个生育期水稻、褐飞虱和拟水狼蛛的荧光物含量均随所施荧光物质浓度的增高而增高。褐飞虱对不同生育期水稻的取食量依次为抽穗期>孕穗期>乳熟期>黄熟期,分别为每克褐飞虱生物量在24 h内摄食水稻17.5910 g, 17.4510 g, 13.8290 g和8.7070 g。拟水狼蛛对褐飞虱的捕食量为乳熟期>孕穗期>抽穗期>黄熟期,分别为每克拟水狼蛛生物量24 h捕食褐飞虱3.6380 g, 3.0830 g, 3.0770和2.8000 g。根据田间调查数据换算为每头拟水狼蛛捕食褐飞虱在孕穗期、抽穗期、乳熟期和黄熟期分别为11头、11头、13头和10头。     

蜘蛛对稻纵卷叶螟和白背飞虱的选择捕食作用

讨论蜘蛛的主要种群拟水狼蛛、食虫瘤胸蛛、粽管巢蛛对稻纵卷叶螟、白背飞虱的选择捕食特性。由结果可见：猎物被捕食量与参试种群编码值（密度）的数量关系可由二次多项式模型技术。当取每科水稻上有稻纵卷叶螟５头,白背飞虱１０头,拟水狼蛛２头,粽管巢蛛２头,食虫瘤胸蛛２头时,蜘蛛种群对白背飞虱有较大的选择捕食比率。     

Predator Interference and the Establishment of Generalist Predator Populations for Biocontrol

We conducted a field experiment to determine the extent to which interference among generalist predators limits their effectiveness as biocontrol agents. We manipulated immigration of a guild of actively hunting generalist ground predators, carabid beetles and lycosid spiders, by intercepting them as they attempted to enter fenced 50-m² vegetable gardens. Immigration was blocked, allowed at the mean rate measured at our field site, or doubled. Altered immigration rates were maintained through a spring garden of cabbage, bean, eggplant, and cucumber, followed by a summer garden of squash. We monitored densities of carabids and lycosids to discover if altering their immigration rate changed their densities in the plots. We also measured densities of other predators on the ground and in plant foliage, pest numbers, and vegetable yields. Doubling the immigration rate of carabids and lycosids approximately doubled the densities of carabids inside the plots, but did not increase lycosid densities. Increasing the rate of immigration of carabids and lycosids depressed densities of nonlycosid ground spiders. In the spring gardens, manipulation of carabid and lycosid immigration did not influence numbers of predators or herbivores in the foliage and did not affect vegetable productivity. In contrast, in the summer gardens, foliage-dwelling predators were lower, pest densities were marginally lower, and squash productivity was higher in the carabid and lycosid immigration plots compared to the no-immigration treatment. Doubling carabid and lycosid immigration rate never increased the magnitude of their effects on other predators, pests, or plant productivity. Predator interference limited lycosid establishment, reduced densities of other predator taxa, and apparently prevented a doubling of carabid densities from having an increased impact on pest numbers. Nevertheless, despite widespread effects of predator interference, allowing immigration of lycosids and carabids increased squash productivity.     

Recolonisation and distribution of spiders and carabids in cereal fields after spring sowing

Generalist predators are important for pest suppression during pest establishment because they may occur in the crop before and during pest arrival. However, different crop management practices can have a negative effect on predator populations. If so, there is a need for recolonisation by the predators to the crop fields. An important pest in Sweden is the bird cherry‐oat aphid, Rhopalosiphum padi, which migrates to cereal fields in spring. In turn, many cereal fields are spring sown and thus are disturbed by harrowing and sowing a short time before aphid arrival. In this study, three different questions about the populations of spiders and carabids in spring cereal crops were asked. First, does sowing in spring have a negative effect on the predators present in the fields? Second, if sowing has a negative effect on predator populations, do they recolonise the fields before pest arrival? Third, how are the predators distributed in the fields? We found that most carabids and most lycosid spiders were not affected by sowing and were distributed uniformly in the fields after sowing. Most linyphiid spiders were negatively affected by sowing, but then they recolonised the fields and were uniformly distributed in the fields after recolonisation. Thus, many spiders and carabids are present in the fields after sowing in spring and have the opportunity to suppress aphids during their establishment phase, which in turn may prevent a possible outbreak.     

Laboratory validation of rubidium marking of herbivorous insects and their predators

A simple and effective marking technique is an invaluable tool for tracking the movement of invertebrates in the field. In order to do this, the technique must be validated in a controlled setting. In the first study, two soft bodied herbivores with different feeding strategies and two of their insect predators, also with different feeding strategies, were marked with rubidium (Rb), an elemental marker previously shown to be effective in marking herbivorous invertebrates. The naturally occurring concentration of Rb was determined for both the herbivores and their predators. Rb concentrations were determined in (1) the herbivore species over several days of feeding on rubidium chloride (RbCl) marked plants; (2) in the predatory species immediately after consuming prey marked at different rates with Rb; and (3) in the predatory species for several days after consuming a single meal of Rb marked prey. The concentration of Rb within the marked herbivores was found to be significantly higher than the naturally occurring concentration after eating RbCl marked plants for to up 8 days. A significantly higher concentration of Rb was found in both predators when fed prey that had been on the RbCl sprayed plants for 2 or 8 days compared with naturally occurring concentrations. There was also a significant difference between the Rb concentrations in the controls and each of days 5, 10 and 15 since feeding in both predators. A second smaller study was carried out to examine the effect of feeding Rb marked prey to spiders. The concentration of Rb in the spiders fed marked prey was significantly higher than that of the controls. This suggests that Rb is an effective way of marking both herbivores and their insect and arachnid predators enabling them to be tracked in the field and to determine their movements across habitats.     

Early season natural control of the brown planthopper, Nilaparvata lugens: the contribution and interaction of two spider species and a predatory bug

Nilaparvata lugens St?l, the Brown Planthopper (BPH), is a major pest in rice. The lycosid Pardosa pseudoannulata (B?senberg & Strand) and the linyphiid Atypena formosana (Oi) are the early dominant predators in irrigated rice. Later, predatory bugs, including the mirid Cyrtorhinus lividipennis Reuter, become dominant. In unsprayed rice, BPH numbers normally remain low. While P. pseudoannulata is known to be a key natural enemy of BPH, the contribution to BPH reduction by the smaller A. formosana is less well known. Due to the size difference, A. formosana may also be an intraguild prey of P. pseudoannulata. To investigate predation on BPH by the two spider species alone, together and in combination with C. lividipennis, two cage experiments were conducted, the first with adult spiders, the second with immature/unmated spiders. In the latter, spiders were introduced with a delay to allow a better establishment of C. lividipennis. In both experiments, BPH numbers were lowest in treatments with more than one predator species present. Intermediate BPH reduction was obtained with P. pseudoannulata followed by A. formosana and C. lividipennis. While P. pseudoannulata can prey upon large nymphs and adult BPH, A. formosana favour early instar BPH, leading to a more even control across instars in treatments with both spider species. Pardosa pseudoannulata numbers increased more with A. formosana or A. formosana and C. lividipennis present. In contrast, P. pseudoannulata reduced A. formosana and C. lividipennis numbers. The presence of C. lividipennis apparently lessened intraguild predation on A. formosana and may be an intraguild prey of A. formosana. Competition for prey may have added to the antagonistic interactions found. From a biological control perspective, the presence of both spiders in early rice is an advantage for the biological control of BPH in rice. In early rice, results show that A. formosana is an important predator of BPH and, like C. lividipennis, can complement control by P. pseudoannulata and serve as intraguild prey for the latter species.     

Enhancing spider families and spider webs in Indian rice fields for conservation biological control,considering local and landscape management

Spiders are omnipresent, occurring in almost all terrestrial habitats. They are generalist predators and important for conservation biocontrol in agricultural fields, helping to reduce pesticide applications. In this study, we examined how spider families and spider web types in rice fields are related to local and landscape management. Samples were taken in differently managed rice fields adjoining either homegarden polycultures or banana monocultures. Furthermore, landscape structure, prey abundance, herb richness and cover were taken into account. The results showed that prey availability explained most of the variation in spiders and their web’s abundance, indicating that spiders in the rice fields can potentially contribute to pest control. Adjacent habitat had no effect on the spider populations, but maintaining fallow fields in the surrounding landscape seems to be a useful measure to promote Erigoninae in rice fields. There was no evidence that local management practices such as fertiliser and pesticide use had an impact on spider families, which appeared to be due to the low level of these inputs. Spider web sampling can complement spider sampling as it detects spiders hidden at the base of the rice tillers, which are likely to be missed by sweep netting. Additionally, tetragnathid webs are easy to observe and thus can be used as an indication for farmers not to spray pesticides as spiders are potentially controlling the pest species. Interviews with farmers made clear that many farmers in the study area showed their interest in management methods that promote biological pest control.     

几种化学农药对稻田优势种蜘蛛杀伤力的研究

用５种化学农药对稻田优势种蜘蛛杀伤力的盆栽与田间进行测试。结果表明,５种化学农药对稻田４种优势种蜘蛛都有较大的杀伤力,总的杀伤率达６２．１％－９１．７％,盆栽施药比田间施药对蜘蛛的杀伤力大。田间试验结果应当比较符合实际;田间试验对照组蛛虫减退的民政部进一步说明,蜘蛛对目标害虫具有良好的控制作用,在晚稻后期,如果蛛虫比在１：５以下,用不着使用化学农药防治。     

Diversity of spiders after spring sowing – influence of farming system and habitat type

Spiders contribute considerably to diversity in agroecosystems and are important components of natural pest control. Farming system and adjacent habitats may influence spider diversity. In this study, diversity of the spider families Lycosidae and Linyphiidae was studied after spring sowing until the time when a common pest (Rhopalosiphum padi) colonizes cereal fields. The spiders were collected with pitfall traps at eight organically or conventionally managed farms around Uppsala, Sweden, in three different habitats at each site: field margin, crop field and the edge between the two. The effects of farming system and habitat type on diversity of lycosids and linyphiids were considered using three different measures (activity density, species richness and composition). The most dominant species of each spider family, Pardosa agrestis (Lycosidae) and Oedothorax apicatus (Linyphiidae), had higher activity density at organic sites, and farming systems also contained different species compositions of both lycosid and linyphiid spiders. Also, linyphiid species richness was higher on conventional sites and linyphiid species composition was influenced by habitat type, in contrast with lycosids. Activity density and species richness of lycosid spiders were, on the other hand, more associated with field margins than linyphiid spiders.     

广东双季稻区杂草地和稻田中捕食性节肢动物的群落动态

用吸虫器采样法,于1998年对广东省大沙镇双季稻区两块相邻的杂草地和稻田中捕食性节肢动物群落的结构进行了研究。在杂草地生境中共采集到73种捕食性节肢动物,其中55种为蜘蛛,18种为昆虫。3月21日,早稻田翻耕前,在杂草地中采集到33种捕食性节肢动物,密度为130头/m²。4月4日,水稻移栽1周后,在杂草地中采到29种捕食性节肢动物,密度为92头/m²;同期在稻田中采到12种捕食性节肢动物,密度为16.2头/m2。5月13日早稻成熟前期,在杂草地中只采到19种捕食性节肢动物,密度为28头/m²;而此期,在稻田中采到27种捕食性节肢动物,密度为53.2头/m²。在晚稻生长期,杂草地捕食性节肢动物与稻田捕食性节肢动物物种数和密度的变化与早稻生长期情况相似。杂草地与稻田两生境间的捕食性节肢动物群落的相似性系数大于0.5,由此可见,这两类生境中捕食性节肢动物的物种组成是非常相似的,具有较多的共有种。杂草地捕食性节肢动物群落可能是稻田捕食性节肢动物群落重建的重要种库之一。     

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.