圆柏大痣小蜂幼虫龄期测定

明确圆柏大痣小蜂Megastigmus sabinae Xu et He（1989）幼虫的最佳分龄指标、幼虫龄数与各虫龄龄期,为探明圆柏大痣小蜂幼虫期的生长规律奠定基础。本研究通过测量圆柏大痣小蜂幼虫上颚关节宽、头宽、体宽和体长4个形态指标,利用频次分布推测幼虫龄数,运用Crosby生长法则和线性回归的方法判断圆柏大痣小蜂幼虫的最佳分龄指标并验证幼虫的龄数。将最佳分龄指标作为龄期判断依据,根据测量结果对其幼虫龄期进行划分。圆柏大痣小蜂幼虫共划分为5个龄期,上颚关节宽为圆柏大痣小蜂幼虫龄期划分的最佳形态指标,各龄幼虫的历期约为30 d、200 d、30 d、30 d、15 d,共305 d,主要以2龄越冬。     

双条杉天牛幼虫龄数的划分(鞘翅目:天牛科)

双条杉天牛 Semanotus bifasciatus Motschulsky 是危害我国侧柏 Platycladus orientalis 和圆柏 Sabina chinensis 的重要钻蛀性害虫,其幼虫龄数及最佳分龄指标的确定是进一步研究其生物学特性、发生规律的基础.本研究通过室内木段饲养法获取不同发育阶段的双条杉天牛幼虫,分别测量幼虫的前胸背板宽、头壳宽和上颚宽3项形态指标.采用频次分析法确定幼虫龄数,运用Crosby生长法则和线性回归进行验证分析.结果表明:双条杉天牛幼虫有5龄,其前胸背板宽符合Dyar氏法则和Crosby生长法则并呈现明显的线性回归关系,可作为幼虫龄数划分的重要指标.1～5龄幼虫前胸背板宽分别为0.574±0.012 mm、1.162±0.013 mm、1.738±0.027 mm、2.760±0.011 mm 和3.492±0.015 mm.前胸背板宽(Y1)和幼虫龄数(X)的最佳线性回归方程为lgY1 = 0.185X-0.340(r =0.9647).本研究明确了双条杉天牛幼虫龄数及最佳分龄指标,为深入研究该虫各生长发育阶段的生物生态学特性提供了参考.     

栗山天牛幼虫龄数和龄期的测定

栗山天牛Massicus raddei (Blessig)是危害我国东北柞树天然林的重要蛀干害虫, 长期营隐蔽性生活, 3年发生1代, 防治困难。幼虫的龄数和龄期测定是害虫预测预报以及制订其科学治理策略的重要依据。本研究于2008-2011年通过林间定期解剖受害树进行取样, 在辽宁省宽甸县采集不同发育阶段的栗山天牛幼虫, 分别测量幼虫上颚长、 主单眼间距、 前胸背板宽、 中胸气门长和体长等5项形态指标, 利用频次分析的统计方法, 测定了栗山天牛幼虫的龄数。结果表明: 栗山天牛幼虫有6龄, 雌雄性幼虫龄数相同。上颚长、 主单眼间距和前胸背板宽3项指标均可用于分龄, 中胸气门长和体长变异较大, 不宜用作幼虫龄数划分。利用种群众数龄期法计算1-6龄幼虫的平均龄期分别为9.25, 266.85, 48.09, 51.29, 260.33和385.71 d, 幼虫期共1 021.52 d。在我国东北地区, 自然条件下栗山天牛世代发生非常整齐而且高度同步, 完成1代发育需跨越4个年份, 幼虫经历3次越冬, 第1年以2-3龄幼虫越冬, 第2年主要以4-5龄幼虫越冬, 第3年全部以末龄幼虫越冬。研究结果进一步明确了栗山天牛幼虫期的生物学特性, 为生产上合理防治该害虫提供了参考依据。     

Determining the number of instars in potato tuber moth Phthorimaea operculella (Zeller) using density‐based DBSCAN clustering

The potato tuber moth (PTM), Phthorimaea operculella (Zeller), is an important pest of Solanaceae crops and especially devastating to potatoes. There is no significant difference in morphological characteristics of PTM from the first to third instar larvae; therefore, it is difficult to directly determine the number of instars of this pest based on morphology. In the present study, head capsule width and length and mandible width of 340 PTM individuals were measured. Density‐based spatial clustering of applications with noise (DBSCAN) clustering was used for instar grouping. The results of DBSCAN clustering were compared with those obtained using Gaussian mixture models and k‐means clustering; the results of the three clustering methods were verified using Brooks–Dyar rule, Crosby rule and linear regression model. The clusters obtained using the three methods were the same and comprised four PTM instars with three morphological characteristics. Moreover, the results of the three methods fit the Brooks–Dyar rule, Crosby rule, frequency analysis and logarithmic regression model well. Head capsule width was the best morphological characteristic for determining the number of instars of PTM, and this characteristic may be used for determining PTM instars in the field. These results show that the DBSCAN clustering method is a promising tool for the identification of insect instars.     

柑桔爆皮虫幼虫龄期的划分

近些年柑桔爆皮虫Agrilus auriventris Saunders在浙江部分柑桔产区暴发危害,幼虫龄数的确定是进一步研究其发生规律、生物学习性、预测预报以及制定综合防治技术的基础。本研究采用田间取样和室内孵化的方法收集柑桔爆皮虫各龄幼虫,测量了幼虫头部口上片最大宽度（Y1）、尾部钳状突最大宽度（Y2）、钳状突最大长度（Y3）、钳状突左侧侧缘最大长度（Y4）等4个形态特征。根据所测数据的频次分布图以及Dyar定律推测柑桔爆皮虫幼虫分为5龄。运用Crosby生长法则和线性回归的方法进行分析,发现口片最大宽度是幼虫分龄的最佳指标。1～5龄幼虫口上片宽度（mm）分别为0.1196±0.0013, 0.2008±0.0030, 0.3304±0.0041, 0.5150±0.0049, 0.7844±0.0040。口上片宽度和幼虫龄数的最佳线性回归方程为y=-0.0766+exp(-1.9883+(0.3675)×x)（R₂＝0.9876）。     

骆驼斯氏副柔线虫病传播媒介西方角蝇和截脉角蝇的幼虫龄期划分

【目的】本研究旨在找出区分西方角蝇Haematobia irritans和截脉角蝇H.titillans幼虫龄期划分标准,为准确鉴定两种角蝇各龄幼虫,研究斯氏副柔线虫在角蝇体内的发育过程,以及制定防控骆驼斯氏副柔线虫病的有效措施等奠定基础。【方法】采用实验室人工孵育两种角蝇幼虫的方法,分别测量不同发育阶段幼虫的虫体长、咽骨体长和咽骨体宽3项指标,利用SPSS Statistics 19.0统计软件对数据进行处理,结合Crosby生长法则和线性回归的方法进行分析,比较两种角蝇幼虫之间差异,以确定两种角蝇幼虫最佳龄期划分标准。【结果】结果表明,两种角蝇的幼虫均分为3龄,咽骨体是两种角蝇幼虫龄期划分的特征性结构,两种角蝇各龄幼虫相同指标的测量值随龄期的增长呈现出相同的增长规律。咽骨体长是划分两种角蝇幼虫龄期的最佳测量指标,咽骨体宽可作为分龄的辅助指标;两种角蝇相邻龄期幼虫的体长变化范围存在相互重叠,不能准确划分角蝇幼虫龄期。【结论】研究表明通过西方角蝇和截脉角蝇幼虫咽骨体的形态特征可简便、快速和准确地鉴定两种角蝇幼虫的龄期。     

基于外部形态特征量化分析判别菱角水螟幼虫龄期

【目的】本实验拟为田间准确快速判别菱角水螟Parapoynx crisonalis(Walker)幼虫龄期提供一种新方法,以便监测其发生规律、预测其发生时间。【方法】本研究通过对幼虫头壳宽、复眼距、体宽和体长4项外部形态指标的测量,运用Crosby生长法则和线性回归分析方法,结合各项指标的频次分布进行分析。【结果】各龄幼虫头壳宽平均值的变异系数和Crosby指数最小,为判别幼虫龄期的最佳分龄指标,幼虫期共分为5龄,1~5龄的头壳宽分别为(0.2493±0.0053)、(0.3454±0.0018)、(0.5079±0.0031)、(0.7419±0.0190)和(1.1287±0.0369)mm,其与龄期数呈线性关系。通过实验室饲养观察菱角水螟幼虫蜕皮次数验证该虫幼虫期分为5个龄期。【结论】头壳宽为判定菱角水螟幼虫龄期的最佳指标,复眼距次之。     

Within‐generation dynamics of leatherjackets (Tipula paludosa Meig.)

Larvae of Tipula paludosa (leatherjackets) are pests of grassland and cereals, and important prey items for a range of farmland birds. Their population dynamics from year to year have been the subject of study, but within‐generation dynamics have received much less attention. The duration and occurrence of instars and size of the population is important to both pest management and bird conservation. Leatherjackets were collected monthly from four grass fields over five generations (October to September). Count data were analysed for sources of variability and used to estimate the timing and duration of instars and population changes over a single generation. Instar durations were correlated with temperature. From the first to third instars, sample counts were strongly influenced by the location of the site and the generation. Fourth instar larvae showed a similar decline in numbers across all sites and generations. The duration and timing of first to third instars was more variable than that of the fourth instar, but there was limited evidence that this was influenced by temperature. Only the durations of the third and fourth instars were correlated. The population decline from April to September coincided with the onset of the fourth instar. Our results show that the factors influencing leatherjacket numbers change over the life cycle, but by the fourth instar, these are biotically driven. The predictability of its numerical decline indicates defined windows for crop damage and availability as prey. The stability of its timing suggests that day length may synchronize the annual cycle. Fixed timing of the fourth instar will have important consequences for the timing of crop damage and the conservation of farmland birds as climate changes.     

桉蝙蛾幼虫实时荧光定量PCR内参基因的筛选

本研究通过筛选桉蝙蛾Endoclita signifer Walker幼虫不同龄期与不同体节中稳定表达的内参基因,为桉蝙蛾基因表达研究提供参考。通过实时荧光定量PCR技术测定5个候选内参基因（ACTIN、GAPDH、TUB、RIB、EF）在桉蝙蛾幼虫不同龄期（3龄、5龄、9龄、12龄）与不同体节（头部、胸部、腹部）及全样品（由所有样品组成）处理中的表达量,后利用GeNorm、NormFinder、BestKeeper对5个候选基因的稳定性进行评估,最后由RefFinder综合分析结果,选出最佳的内参基因。基于4种分析方法的评估可知,桉蝙蛾5龄和9龄幼虫的不同体节、不同龄期幼虫的头部和胸部中内参基因的最佳数目为2,而3龄和12龄幼虫的不同体节、不同龄期幼虫的腹部及全样本中内参基因的最佳数目为3。3龄、5龄、9龄和12龄幼虫的不同体节中可分别选择ACTIN+RIB+GAPDH、EF+RIB、GAPDH+EF和ACTIN+RIB+GAPDH作为最稳定的内参基因组合;EF+RIB、RIB+GAPDH和EF+GAPDH+ACTIN可分别作为不同龄期幼虫头部、胸部和腹部的最佳内参基因组合;综合考虑桉蝙蛾幼虫不同龄期与不同体节的影响时,可选择RIB、ACTIN和GAPDH作为内参基因。     

杨黑点叶蜂幼虫龄数和龄期

夏季,采用室内常温、常光照条件下饲养的方法和解剖镜测微技术,研究杨黑点叶蜂Pristophora conjugata Dahlbom幼虫龄数和龄期。结果表明,杨黑点叶蜂雄性幼虫共5龄,雌性幼虫共6龄;各龄幼虫头宽值分别为(mm):0.585~0.849;0.849~1.371;1.371~1.960;1.960~2.350;2.350~2.868;2.868。根据幼虫头宽值确定幼虫所处龄期,为准确掌握防治时期提供科学依据。     

Development and feeding efficiency of Malacosoma neustrium larvae reared with Quercus spp. leaves

Observations on larval development of Malacosoma neustrium were conducted both in a cork oak stand and in the laboratory by using leaves of different host trees (cork oak, holm oak and downy oak) as food source. Instars were determined using head capsule and frass measurements. In the field the larvae progressed up to the fifth instar before pupating, and the increase in head capsule width followed Dyars Rule with a rate of increase (R.I.) value of 1.74. The same number of instars was determined for the larvae reared with cork oak (R.I. = 1.73) and holm oak (R.I. = 1.70) leaves. The caterpillars reared with downy oak foliage completed larval development in five, six and seven instars and the R.I. values obtained were 1.60, 1.52 and 1.44 respectively. A lower mortality was recorded for the larvae reared on holm oak. Growth and feeding indices were determined for the larvae from the third up to the last instar. The highest leaf consumption was detected for the fifth instar larvae reared on holm oak. For the caterpillars which completed five instars before pupating, the relative consumption rate (RCR) decreased from the third up to the fifth instar: from 4.8 to 1.7 (cork oak), from 7.4 to 3.3 (holm oak) and from 14.3 to 2.1 (downy oak). The relative growth rate (RGR) was highest during the fourth stadium (0.24, 0.27 and 0.33 for larvae reared with cork oak, holm oak and downy oak leaves respectively) and decreased in the fifth instar (0.09, 0.14 and 0.14 for larvae reared with cork oak, holm oak and downy oak leaves respectively), probably because of greater expense of energy due to the approach of maturity. Feeding and growth indices could be useful to define a defoliation prediction model.     

甜菜夜蛾不同龄期幼虫对药剂的敏感性及其与酶活力的关系

【目的】明确甜菜夜蛾Spodoptera exigua(Hübner)不同龄期幼虫对甲氨基阿维菌素苯甲酸盐和毒死蜱的敏感性及其与羧酸酯酶、多功能氧化酶、谷胱甘肽S-转移酶和乙酰胆碱酯酶活性的相关性。【方法】采用室内生物测定方法检测甜菜夜蛾不同龄期幼虫对药剂的敏感性,并检测了不同龄期幼虫体内羧酸酯酶、多功能氧化酶、谷胱甘肽S-转移酶和乙酰胆碱酯酶的活力。【结果】在所测定的5个龄期中,随龄期增加,敏感性逐渐降低,其中1~5龄幼虫对甲氨基阿维菌素苯甲酸盐的LC50分别为0.1010、0.3561、0.7568、1.4325和8.4390 mg/L,对毒死蜱的LC50分别为27.4632、46.8495、87.5222、129.3217和1 356.6770 mg/L。单头幼虫的羧酸酯酶、多功能氧化酶、谷胱甘肽S-转移酶和乙酰胆碱酯酶活力随虫龄的增加而提高,与龄期间对药剂的敏感性呈负相关(由于外源化合物摄入量减少,5龄单头幼虫的多功能氧化酶活力略有降低)。【结论】甜菜夜蛾不同龄期幼虫对药剂的敏感性存在非常明显的差异,在田间防治中,应选择对杀虫剂敏感性较高的低龄幼虫作为最佳防治时期。     

麦长管蚜虫龄鉴别特征

【目的】为明确麦长管蚜Sitobion avenae (Fabricius)虫龄鉴别特征, 达到快速鉴别的目的。【方法】在成像观察的基础上, 测定无翅型和有翅型个体不同虫龄的体长、 体宽、 头壳宽、 触角长、 腹管长和后足胫节长6项指标。【结果】麦长管蚜不同翅型个体的体长、 体宽、 头壳宽、 触角长、 腹管长和后足胫节长在虫龄间均存在显著差异, 其中体长、 体宽、 头壳宽和触角长在相邻虫龄之间重叠程度大, 后足胫节长的重叠百分比极小或无重叠; 除有翅型个体4龄若蚜和成蚜之间存在13.93%的重叠外, 腹管长在不同翅型的其他相邻虫龄之间重叠百分比均极小或无重叠, 说明后足胫节长和腹管长可作为虫龄鉴定的主要特征。翅、 触角和尾片的其他外部形态特征在虫龄间也存在一定差异： 3-4龄有翅型若蚜和成蚜虫个体前胸的膨大程度及其翅的长度明显大于同一龄期的无翅型个体, 可用于蚜虫翅型的分辨以及3-4龄有翅若蚜和成蚜的鉴别; 麦长管蚜1和2龄若蚜触角均为5节, 3-4龄若蚜和成蚜的触角均为6节; 同时, 除了成蚜具有完整的尾片外, 1-4龄若蚜尾片均不发达, 说明触角的节数和尾片的发达程度可作为麦长管蚜不同龄期形态鉴别的辅助特征。【结论】以腹管和后足胫节作为麦长管蚜虫龄鉴别的主要特征, 配合其他辅助特征, 如翅的大小、 触角的节数以及尾片的发达程度等, 可达到快速鉴别不同翅型不同龄期蚜虫的目的。     

Achieving high sexual size dimorphism in insects: females add instars

Abstract.  1. In arthropods, the evolution of sexual size dimorphism (SSD) may be constrained by a physiological limit on growth within each particular larval instar. A high SSD could, however, be attained if the larvae of the larger sex pass through a higher number of larval instars.
2. Based on a survey of published case studies, the present review shows that sex-related difference in the number of instars is a widespread phenomenon among insects. In the great majority of species with a sexually dimorphic instar number, females develop through a higher number of instars than males.
3. Female-biased sexual dimorphism in final sizes in species with sexually dimorphic instar number was found to considerably exceed a previously estimated median value of SSD for insects in general. This suggests a causal connection between high female-biased SSD, and additional instars in females. Adding an extra instar to larval development allows an insect to increase its adult size at the expense of prolonged larval development.
4. As in the case of additional instars, SSD is fully formed late in ontogeny, larval growth schedules and imaginal sizes can be optimised independently. No conflict between selective pressures operating in juvenile and adult stages is therefore expected.
5. In most species considered, the number of instars also varied within the sexes. Phenotypic plasticity in instar number may thus be a precondition for a sexual difference in instar number to evolve.     

榆木蠹蛾幼虫龄数的确定

为弄清榆木蠹蛾Holcocerus vicarius Walker幼虫的发育情况及预测其发生时间, 通过测量榆木蠹蛾幼虫的头壳宽、 体长、 体宽、 前胸背板宽、 上颚长和上颚宽, 运用Crosby生长法则和线性回归方法分析来找出判定幼虫龄数的最佳形态指标, 推断其幼虫的龄数。结果表明： 各龄幼虫头壳宽平均值的变异系数和Crosby指数最小, 其他5项指标的变异系数和Crosby指数较大, 头壳宽为最佳分龄指标。根据头壳宽将榆木蠹蛾幼虫分为20龄, 不同龄幼虫头壳宽值符合Dyar定律提出的幼虫头壳宽增长规律, 头壳宽和龄数的回归方程为y=0.233+1.686x+0.127x²-0.005x³ （R²=0.996）。榆木蠹蛾幼虫龄数的确定为研究其发生规律、 生物学习性及进行综合防治提供依据。     

Instar determination for sugarcane internode borer Chilo sacchariphagus indicus (Kapur) (Lepidoptera: Crambidae)

Internode borer (INB), Chilo sacchariphagus indicus has been a serious threat to sugarcane cultivation for more than six decades. We have determined the number of instars for INB through frequency distribution analysis of cast head capsule widths. This is the first report, which proves that the INB of sugarcane passes through five larval instars to attain its pupal stage. The number of instars determined by kernel density estimation was in corroboration with the number of instars observed in the laboratory. The mean Dyar’s ratios for both the instar-wise observed data on head capsule widths and the theoretical data derived from the frequency distribution analysis were one and the same (1.46). Linear regression (R² > 0.998) between the instar numbers and their corresponding mean head capsule widths reaffirmed that no instar has been overlooked. Further, the theoretical misclassification probabilities of 0.16–1.97% indicates that the chance of misidentifying an INB instar into its preceding or succeeding one is very remote. Since the determination of the exact number of instars in a pest species is a pre-requisite for developing appropriate management strategies, the outcome of this study holds great promise in managing the most notorious Crambid borer of sugarcane.     

Dry-matter budgets for Diacrisia casignetum larvae fed on sunflower leaves

Larvae of Diacrisia casignetum Kollar were reared in groups of 100, 50 and 10 on fresh sunflower leaves at 27 ± 1°C temperature, 75 ± 5% r.h. and 12 h light each day. Rates of feeding, excretion and weight gain increased with age of the larva and were greatest in the sixth instar. Differences in these rates attributable to density were statistically heterogeneous (P < 0.001) whereas, of those attributable to instar, the weight gain was significant (P < 0.10). The second-instar larvae had highest levels of protein and carbohydrates in the body tissues; and the sixth-instar larvae had, the least. The pattern of protein assimilation in various instars was similar to that of glycogen except that proportional differences in the latter were pronounced in fifth and sixth instars. Consumption index, growth rate and approximate digestibility were high in the early instars whereas efficiencies of conversion of ingested and digested food were high in advanced instars. Food utilization, as reflected by efficiency of conversion of ingested and digested values in advanced instars, indicated the amount needed for maintenance decreased and more energy was left for growth and reproduction.     

Larval biometry of Simulium rubrithorax (Diptera: Simuliidae) and size comparison between populations in the states of Minas Gerais and Roraima,Brazil

The number of larval instars of Simulium (Hemicnetha) rubrithorax Lutz (Diptera: Nematocera) was determined using the lateral length of the head capsule. In this study 1,035 larvae, of different sizes, were measured (639 from the state of Roraima and 396 from the state of Minas Gerais). A frequency distribution analysis was carried out on the measurements of the lateral length of the head capsule to determine the number of larval instars. The limits of each instar were defined by the lower frequency of the measurements falling in a range of values, by the presence of the "egg burster" that characterizes the first larval instar, and by the developmental stage of the gill histoblast. The determination of the instar number was tested using a Student's t-test (p < 0.05), the Dyar rule and the Crosby growth rule. The results indicate the existence of 7 larval instars for this species, although this result was not in accordance to the Crosby rule. Last-instar larvae from two widely separated geographical populations (Roraima and Minas Gerais), collected in habitats with different water temperature were compared and no differences (p > 0.05) were observed between them.     

Caste Determination in Bombus terrestris: Differences in Development and Rates of JH Biosynthesis between Queen and Worker Larvae

To study the possible role of juvenile hormone in caste determination in Bombus terrestris, we measured development and rates of juvenile hormone biosynthesis in vitro in larvae destined to develop into either workers or queens. Larvae of both castes developed through four instars and had the same growth rates. However, the duration of the instars was longer for queen larvae, and their head width at the third and fourth instars was significantly larger. After validating the well-known radiochemical assay of JH for bumble bee larvae, we show that worker larvae corpora allata exhibited a constant and low rate of JH biosynthesis, never more than 5 pmol JH/h/pair. Queen larvae, in contrast, had two peaks of JH biosynthesis: a small one during the first instar, which has previously been correlated with caste determination; and a large peak, previously undetected, above 40 pmol JH/h/pair, during the second and third instars. We suggest that caste determination in this species is mediated by JH and that the duration of larval instars is a key factor. The possibility that the queen influences caste determination via an effect on instar duration is also discussed. Copyright 1997 Elsevier Science Ltd. All rights reserved     

油茶象幼虫虫龄的划分

【目的】油茶象 Curculio chinensis Chevrolat是我国特有木本油料树种--油茶 Camellia meiocarpa 的专性蛀果害虫,常导致大量落果。幼虫准确分龄是其生物学、生态学及防控研究的基础,但对钻蛀性昆虫来说,这非常困难。本研究旨在明确研究样地油茶象幼虫龄数及各龄形态指标极差,试图探讨确定钻蛀性昆虫龄数及合理划分虫龄的可靠方法。【方法】收集了1 253头不同发育阶段的幼虫,测量头壳宽、头壳长和上颚宽3个形态指标,用多峰拟合分析频次分布资料,结合戴氏法则判断幼虫龄数。以正态曲线交点作为相邻虫龄分界点,计算各龄幼虫测量指标的平均值、极差、增长率及误判率。【结果】头壳宽、头壳长和上颚宽频次分布多峰拟合均呈显著的5个正态峰（P＜0.01）,对应5个虫龄;头壳宽、头壳长和上颚宽3个形态指标均以对3龄幼虫的误判率最大,分别为6.04%,7.03%和6.51%,而对其他虫龄误判率均小于5%,提示3个形态指标均可作为油茶象虫龄划分的可靠依据,以头壳宽最佳。各龄幼虫头壳宽、头壳长及上颚宽增长率依次为1.41~1.54,1.43~1.61及1.44~1.64,基本恒定,其平均值的自然对数与虫龄均呈极显著线性正相关（P＜0.01）,油茶象幼虫头壳生长呈间断性几何级数增长,符合戴氏法则。【结论】油茶象幼虫具5个虫龄,不同于前人报道的仅4个虫龄;多峰拟合可用于确定钻蛀性昆虫或野外种群的龄数,特别是为相邻虫龄形态指标重叠区虫龄划分提供有效方法。