川硬皮肿腿蜂幼虫龄期的划分

通过对川硬皮肿腿蜂幼虫头壳宽度和长度的测定,推断该虫幼期有5龄。1~5龄幼虫的头壳宽度分别为0.1221±0.0017,0.1574±0.0019,0.2030±0.0019,0.2454±0.0020,0.2886±0.0035 mm。经统计分析得到其龄期y与幼虫头壳宽度x的关系式为y=23.72x-1.8222。1~5龄幼虫的头壳长度分别为0.07946±0.0017,0.1039±0.0013,0.1260±0.0014,0.1624±0.0016,0.2008±0.0032 mm。经统计分析得到其龄期y与幼虫头壳长度x的关系式为y=32.694x-1.3977。同时得出幼虫头壳长度y和头壳宽度x的关系式为y=0.7159x-0.011。     

长木蜂幼虫龄期的划分

长木蜂Xylocopa tranquebarorum幼虫龄期的确定是进一步研究巢室行为、生活规律以及制定保护策略的理论基础。本研究采用田间取样和室内孵化的方法收集长木蜂各龄幼虫,测量了幼虫头壳宽度、体长和体重3个形态指标。根据所测数据的频次分布图以及Dyar定律推测长木蜂幼虫分为4龄。1-4龄幼虫的头壳宽度分别为1.405 mm,1.783 mm,2.084 mm,2.250 mm。统计分析得出其龄期y与幼虫头壳宽度x的关系为y=0.2836x+1.1715(R2=0.9724)。     

眉斑并脊天牛幼虫龄数及各龄特征

测定头壳宽度室内观察结果表明,眉斑并脊天牛Glenea cantor(Fabricius)幼虫有4龄。1~4龄幼虫的头壳宽度分别为(0.66±0.20),(1.45±0.20),(2.22±0.23),(3.26±0.29)mm。其龄数(Y)与幼虫头壳宽(X)度符合关系式Y=0.2975+1.1606X。在25℃条件下,1~4龄幼虫的平均龄期分别为(5.25±0.60),(4.94±0.58),(5.98±0.63)d和(22.92±1.28)d,整个幼虫期为(39.09±2.14)d。还对眉斑并脊天牛各龄幼虫的形态特征作了描述。     

法氏柴胡宽蛾幼虫龄期的划分

【目的】法氏柴胡宽蛾Depressaria falkovitshi Lvovsky为三岛柴胡的一种优势害虫,主要以幼虫危害柴胡的叶片、茎尖、花序,幼虫龄期的确定可以为其生物学特性的研究和防治措施的制定与实施提供理论依据。【方法】本文通过测量法氏柴胡宽蛾幼虫头壳宽度和体长,根据所测数据的频次分布及Dyar定律推测出法氏柴胡宽蛾幼虫的虫龄数。运用Crosby生长法则和线性回归分析验证分龄的合理性。【结果】研究表明,法氏柴胡宽蛾的幼虫期共分为5龄,1~5龄幼虫的头壳宽度(mm)分别为0.163±0.006,0.262±0.012,0.437±0.025,0.690±0.038,1.116±0.051。幼虫头壳宽度(y)与虫龄(x)的回归方程为y=0.101e~(0.4815x),R~2=0.9998。【结论】头壳宽度适宜于法氏柴胡宽蛾幼虫期的分龄,而体长由于变异大不宜用作幼虫龄期的划分。     

二点委夜蛾幼虫虫龄的测定

【目的】二点委夜蛾Athetis lepigone(M?schler),属鳞翅目夜蛾科。我国于2005年7月在河北省夏玉米田首次发现。近年来,该虫发生范围不断扩大,为害日益加重,因此应制定科学有效的防治策略。幼虫的虫龄和龄期测定是害虫预测预报以及制定科学防治策略的重要依据。【方法】本文通过测量二点委夜蛾幼虫头壳宽度、体长、体重,对幼虫虫龄的划分进行了研究。根据所测数据的频次分布图及Dyar定律推测幼虫虫龄数,并运用Crosby生长法则和线性回归的方法进行验证。【结果】经测量,幼虫头壳宽度值呈现出5个明显的集中区,1~5龄幼虫头壳宽度分别为0.50~0.62、0.64~0.76、0.82~0.94、1.00~1.12、1.24~1.40 mm。幼虫体长呈现出4个较明显的集中区,分别为2.00~6.50、7.50~12.50、14.50~17.50、18.50~23.00 mm。而实际观察测得1~5龄幼虫体长范围分别为1.96~3.60、2.78~4.10、3.98~6.20、5.38~12.48、14.06~22.96 mm。1~5龄幼虫体重范围分别为<0.0001、0.0003~0.0009、0.0005~0.0036、0.0027~0.0240、0.0337~0.1332 g。【结论】研究结果表明,幼虫头壳宽度可用于分龄,二点委夜蛾幼虫期共分为5龄。头壳宽度y与幼虫虫龄x的回归方程为y=0.4579e0.2121x。幼虫体长和体重在各龄间重叠度较大,不宜用于幼虫虫龄的划分。     

异斑小字大蚕蛾幼虫形态、龄期与生活史研究

【目的】通过观察异斑小字大蚕蛾Cricula variabilis的各虫态发育特征,掌握其基本生活史、幼虫各龄形态特征及区分方法。【方法】在室内进行饲养观察,通过测量幼虫头壳宽、体长、体宽3个指标并计算Brooks指数和Crosby指数,结合线性回归方法对得到的数据进行拟合,确定最佳分龄指标。【结果】异斑小字大蚕蛾一个世代共(77.86±1.09)d,蛹期占29.44%,卵期占14.46%,成虫期占6.19%。幼虫共6龄,历期最长,占整个世代的49.91%,且每个龄期随虫龄的增长而增加。运用Dyar法则与Crosby生长法则验证了头壳宽是幼虫最合理的分龄指标。通过对头壳宽、体长、体宽3个分龄指标的进行线性回归方法分析,头壳宽的指数、二次、三次线性方程来划分幼虫龄期的效果较优,其回归方程分别为y=0.103 8x~2-0.026 2x+0.735 8(R~2=0.996 5)、y=0.572 6e~(0.340 4x)(R~2=0.995 6)、y=0.001 5x~3+0.087 9x~2+0.021 8x+0.697 6(R~2=0.996 5)。【结论】本研究描述了异斑小字大蚕蛾各龄期幼虫的形态特征,和明确幼虫共6龄,头壳宽是幼虫分龄最合适的指标。     

黄羽摇蚊Chironomus flaviplumus Tokunaga幼虫龄期的研究

[目的]探寻黄羽摇蚊Chironomus flaviplumus Tokunaga幼虫最佳分龄形态指标并判断其龄数,准确区分其幼虫龄期。[方法]本文采用实验室内人工养殖定期取样观察的方法,分别测量了不同发育阶段摇蚊幼虫的头壳长、颏中齿顶端至冠突前缘间距离、头壳宽、颏宽、颏中齿宽、触角长、触角基节长、触角除基节以外2~5节长、上颚长、腹颏板长、腹颏板宽11项形态指标,运用Crosby生长法则、频次分析、回归方法分析对11项形态指标测量数据进行统计分析,选择判定幼虫龄数的最佳形态指标,推断其幼虫的龄数及龄期。[结果]黄羽摇蚊幼虫可分为4个龄期,颏宽为最佳的分龄形态指标,1~4龄幼虫的颏宽(μm)分别为(30.9008±0.3253),(52.2114±0.7172),(98.6165±0.6146),(171.2985±0.5582)。幼虫颏宽(y)与龄期(x)的回归方程为y=0.1971x~3+11.365x~2-14.163x+33.502,R~2=0.9827。另外,Y2(颏中齿顶端至冠突前缘间距离)、Y5(颏中齿宽)和Y9(上颚长)也可以作为分龄的辅助指标。选取颏宽对各龄期持续时间进行推测,得出1~4龄幼虫的龄期分别为2~3、2~4、5~6、7d,幼虫期共为16~20d。[结论]黄羽摇蚊幼虫具有4个龄期,颏宽为最佳分龄形态指标,幼虫期共为16~20d。     

绿豆象幼虫虫龄的划分及末龄幼虫头部形态和感器观察

【目的】明确绿豆象Callosobruchus chinensis幼虫的龄期,了解其末龄幼虫头部感受器的种类、形态和分布。【方法】测量绿豆象幼虫体长、头壳宽和上颚宽,根据所得数据的频次分布图、关系拟合结果和戴氏法则确定绿豆象最佳分龄指标,明确幼虫虫龄数,并利用Crosby生长法则和线性回归的方法进行验证;采用扫描电镜对末龄幼虫头部形态及感受器进行观察。【结果】绿豆象体长、头壳宽和上颚宽的频次分布均呈显著的4个峰,因此推断绿豆象幼虫为4个虫龄。各龄的体长变幅分别为1.581～2.556, 2.406～3.381, 3.381～4.281和4.206～4.881 mm,头壳宽度变幅分别为0.444～0.689, 0.654～0.934, 0.934～1.179和1.144～1.389 mm,上颚宽变幅分别为0.080～0.256, 0.234～0.344, 0.322～0.542和0.542～0.652 mm。体长、头壳宽和上颚宽均符合戴氏法则和Crosby生长法则,并呈现明显的线性关系,因此体长、头壳宽和上颚宽可作为绿豆象幼虫龄期划分的重要指标。头壳宽的Crosby指数均小于体长和上颚宽的Crosby指数,且头壳宽与体长测量值的对数值与幼虫龄期的相关系数要优于上颚宽测量值的对数值与幼虫龄期的相关系数,因此可将头壳宽作为最佳分龄指标。绿豆象末龄幼虫头部感器共有锥形感器、毛形感器、瓶形感器、刺形感器、板形感器、栓锥形感器和坛形感器7种感器,主要分布于触角、下颚须、上唇和上颚。【结论】绿豆象幼虫分龄形态指标和头部形态观察为研究其行为活动及综合防治提供理论基础。     

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。     

蜂巢奇露尾甲幼虫龄期的划分

为了明确蜂巢奇露尾甲Aethina tumida Murray幼虫的龄期和最佳分龄指标,本研究分别对不同发育阶段幼虫的头壳宽进行测量,根据各指标的频次分布结果初步确定龄期,并运用Crosby生长法则和线性回归方法进行验证分析。结果表明：蜂巢奇露尾甲幼虫可分为4龄,1~4龄头壳宽度平均值分别为0.1842 mm、0.2942 mm、0.4613 mm、0.7280 mm;此外,本文还对蜂巢奇露尾甲幼虫的形态特征进行描述。本文为研究蜂巢奇露尾甲的发生规律、生物学特性及制定防治措施等提供参考。     

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。     

Instar determination for Pissodes castaneus (Coleoptera: Curculionidae) using head capsule widths and lengths

The aim of this research was to assess the larval instar number of Pissodes castaneus (De Geer) and to facilitate the study of its biology by identifying a reliable method to determine the instar of individual larvae. The larvae of this weevil were collected in central Italy in 2004, and their head capsules were measured by means of a binocular microscope. Head capsule width and length data were analyzed using Hcap, a computer program that use the distribution of size measures to determine instar separation rules. To determine instar number, the Gaines and Campbell method, which represents the perfect geometric progression of size measures (Dyar's rule) by a regression line, was also used. This study identified four larval instars of P. castaneus and found that head capsule widths and lengths followed Dyar's rule and reliably distinguished instars.     

沙棘木蠹蛾幼虫龄期的初步研究

通过测量沙棘木蠹蛾Holcocerus hippophaecolusHua,Chou,FangetChen幼虫的头壳宽、体长、体宽、上颚长和宽等指标,确定其幼虫共有16龄,不同龄幼虫的头壳宽值符合Dyar氏发现的幼虫头壳宽增长规律。同时,探讨了不同龄幼虫的臀足趾钩数、前胸侧毛L1、L2和L3以及腹足大小等指标之间的关系,结果表明:除臀足趾钩数在不同龄幼虫间的数量变化无明显规律,无法用于幼虫的龄期划分外,其它指标均呈现较明显的线性回归关系,初步判断,这些指标可以用于沙棘木蠹蛾不同龄期幼虫的划分。     

白蜡外齿茎蜂幼虫龄数和龄期测定

为掌握白蜡外齿茎蜂Stenocephus fraxini幼虫的龄数和发育历期,本文测量了幼虫体长、头宽、体宽(胸部第3节)、尾铗长和尾铗基径宽等5项指标.经频次分布和回归分析,结果表明:白蜡外齿茎蜂幼虫可分5龄.头宽和尾铗基径宽均可作为分龄指标.各龄头宽值分别为:0.414±0.002、0.526±0.002、0.713±0.005、1.003±0.006、1.398±0.010 mm;尾铗基径宽值分别为:0.060±0.001、0.095±0.001、0.150±0.002、0.231±0.002、0.344±0.005 mm.1～5龄幼虫平均龄期分别为2.5、3.5、5、8、40 d,整个幼虫历期约50～70 d,平均60 d左右.     

RELIABILITY OF USING HEAD CAPSULE WIDTH AND BODY LENGTH TO IDENTIFY LARVAL INSTARS OF AEDES VIGILAX (DIPTERA: CULICIDAE)

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Discriminant function analyses on head capsule width and body length of 940 larvae of the saltmarsh mosquito Aedes vigilax (Skuse) were used to determine their reliability in distinguishing between different instars. Of larvae reared under different temperature/salinity regimes, 99.4% were correctly graded on the basis of head capsule width whereas only 88.0% of determinations were correct when body length was used. Thus head capsule width was found to be a reliable character to grade instars regardless of rearing conditions.     

Head capsule width as an instar indicator for larvae of the cranberry fruitworm (Lepidoptera: Pyralidae) in southeastern New Brunswick

The objective of this study was to determine the number of instars of the cranberry fruitworm Acrobasis vaccinii Riley in southeastern New Brunswick based on the distribution of head capsule widths from field and laboratory observations. In 2000, head capsules from field samples were measured across their widest point, and the results were plotted against observed frequencies. The data from field samples suggested that A. vaccinii exhibited five instars in 2000. In 2001, larvae were reared in the laboratory until the final molt, and head capsules were counted and measured. The results were also plotted against observed frequencies. None of the laboratory specimens exhibited more than five instars, supporting the results of the previous year. Various factors are invoked to explain the difference between these results and those of a previous study conducted 50 yr earlier and 200 km away, in which six instars and larger head capsules were reported.     

Development,growth and metabolic rate of Hermetia illucens larvae

The larvae of Hermetia illucens are known to successfully bio‐convert a vast range of organic substrates into high protein and fat biomass, but little is known about the larval instars. During this research, larval head capsules and biomass growth were measured daily and the specific metabolic rate of larger instars were considered. The head capsule measurements revealed that H. illucens pass through 6 actively feeding larval stadia before entering the last nonfeeding but migrating 7th stadium. Larval growth follows a sigmoid curve with slowly accelerating growth in the earlier stadia and decelerating growth in the latest stadia. In contrast, development was fast until reaching stadium 6 and then slowed down. Accordingly, the specific metabolic rate was high in instars 3, 4 and 5 and reduced in instars 6 and 7.     

Interactive effect of diet and temperature on instar numbers in Spodoptera litura,with reference to head capsule width and weight

The effects of diet and temperature on instar numbers and head capsule width in Spodoptera litura F. were compared among individuals reared on an artificial diet, lettuce and perilla leaves at 25 and 30 °C. The number of instars that the insect completed varied as diet and temperature were changed. All the larvae developed through seven instars at 25 °C regardless of diet, but at 30 °C, the number of instars varied depending on the diet. All larvae fed on lettuce leaves had six instars, while larvae fed on the artificial diet passed through seven instars. On perilla, 52% of larval individuals had six instars, and the rest had seven instars. Head capsule width could be used effectively to determine the developmental stage of individual larvae. The frequency distribution of head capsule width showed six or seven distinct peaks, depending on diet and temperature conditions. The relationship between mean head capsule width and weight of larvae was described using an exponential model.