栎黄枯叶蛾幼虫龄数的确定

【目的】为明确栎黄枯叶蛾Trabala vishnou gigantina Yang幼虫的发育状况,以便进行预测预报及采取防治措施。【方法】通过野外采样获取不同发育状态的栎黄枯叶蛾幼虫,对其头壳宽度,体长,体宽,额宽,上颚基部宽和单眼间距6项形态指标进行测量,利用Crosby生长法则和线性回归方法,推断栎黄枯叶蛾幼虫的龄数。【结果】栎黄枯叶蛾幼虫有7龄,头壳宽度为最佳分龄结构。单眼间距、额宽和上颚宽3项指标均可作为分龄的辅助手段,体长和体宽变异较大,不宜用作幼虫龄数划分。【结论】研究结果为生产上合理防治该害虫提供了参考依据。     

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。     

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。     

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。     

栗山天牛幼虫天敌白蜡吉丁肿腿蜂的转主寄主研究

在利用白蜡吉丁肿腿蜂Sclerodermus pupariae防治世代周期长、 发育整齐的害虫栗山天牛Massicus raddei中, 我们发现该天敌只在寄主1-3龄幼虫时具有良好的寄生效果, 而对3龄以上的中老龄幼虫基本不寄生。为了了解释放白蜡吉丁肿腿蜂后其种群能否在栎树林间延续下去, 达到持续控制靶标害虫的效果, 我们调查了其在栎树林间的转主寄主。结果表明： 白蜡吉丁肿腿蜂除了寄生栗山天牛外, 还能寄生双簇天牛Moechotypa diphysis、 四点象天牛Mesosa myops和栎块斑吉丁Lamprodila virgata幼虫。白蜡吉丁肿腿蜂寄生不同转主寄主幼虫的成功率差异显著, 对栎块斑吉丁和双簇天牛幼虫的寄生率最高, 分别为76.67%和73.33%。寄生上述4种寄主时, 其雌蜂在不同寄主上的产卵前期、 产卵量及第2代雌蜂出蜂量、 出蜂率、 体长和寿命等差异不显著, 只有幼虫期和蛹期历期及第2代雌蜂有翅率和雌雄性比略有差异。室内模拟林间寄生试验表明, 白蜡吉丁肿腿蜂对双簇天牛和四点象天牛幼虫的寄生率较高。对双簇天牛和四点象天牛野外生活史研究发现, 这2种天牛幼虫在白蜡吉丁肿腿蜂不适宜寄生的栗山天牛中老龄幼虫期、 蛹期和成虫期均大量存在, 表明双簇天牛和四点象天牛是白蜡吉丁肿腿蜂在栎树林中的主要转主寄主。本研究说明, 在利用白蜡吉丁肿腿蜂生物防治栗山天牛中, 白蜡吉丁肿腿蜂在林间寄生栗山天牛的1-3龄幼虫后, 可转移寄生双簇天牛等转主寄主, 以延续其种群, 待下一代栗山天牛幼龄幼虫出现时再转移寄生栗山天牛, 达到持续控制栗山天牛的防治效果。     

梨小食心虫幼虫龄数和龄期的划分

【目的】为明确梨小食心虫Grapholitha molesta(Busck)幼虫的发育状况,以便进行预测预报及采取防治措施。【方法】试验对幼虫头壳宽、上颚宽、体长和体宽4项指标进行测量。【结果】头壳宽和上颚宽符合Dyar法则和Crosby法则并呈现明显的线性回归关系,可作为龄期划分的重要指标,确定其龄期为5龄。室内26℃温度下饲养幼虫历期约为15 d,1~4 d为1龄期、4~7 d为2龄期、6~10 d为3龄期、8~12 d为4龄期、11~15 d为5龄期。【结论】幼虫刚毛、体色、斑纹也可作为龄期划分辅助参考方法,体长和体宽变异性较大,不宜作为幼虫龄数划分的标准。     

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...     

薜荔榕小蜂幼虫虫龄的划分

【目的】薜荔Ficus pumila. var.pumila既是热带和亚热带植物生态系统的关键树种,也是城市垂直绿化的重要树种。薜荔榕小蜂Wiebesia pumilae是薜荔的专性传粉蜂。榕小蜂幼虫长期生活于隐头花序内的虫瘿中,虫体小,龄期长,观测困难。本研究旨在建立榕小蜂幼虫虫龄的划分标准,探讨确定隐蔽性昆虫幼虫龄数和龄期的可靠方法。【方法】共采集447头不同龄期的薜荔榕小蜂幼虫,对幼虫头壳宽、第3节宽、体长和周长4个形态指标进行测量,利用频次分布法确定幼虫龄数,并用众数龄期测定法计算各龄幼虫的龄期。【结果】幼虫头壳宽、第3节宽、体长和周长的频次分布均呈5个峰,表明幼虫发育龄数为5龄。因第3节宽的变异系数大于20%,不适合作为虫龄划分的指标。回归分析表明幼虫头壳宽、体长和周长的测量值与虫龄之间均呈极显著正相关性(P<0.01),由于体长测量值与虫龄回归曲线的判定系数(R²)最高,因此体长为分龄的最佳测量指标,其回归方程为y=0.14e^0.55x(P<0.01,R²=0.97)。夏季薜荔榕小蜂1-5龄幼虫的...     

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。     

福建省突颚反颚茧蜂属一新种(膜翅目:茧蜂科)(英)

笔者在整理福建省的茧蜂标本时,发现一新种:赭胸反颚茧蜂Heratemis ustulatus Wu et Chen。该新种与Heratemis vegeta(Papp)近缘,但新种的头部黑褐色,中胸背板红褐色,产卵器与腹部等长。 该新种的主要鉴别特征:雌蜂体长3.7mm。体黑褐色,中胸背板红褐色。无后头瘤,后单眼间距POL及单复眼距(OOL)分别为后单眼直径(D)的1.3和3.0倍。上颚4齿(第4齿在第1、2齿间)。第1、2鞭节长为第3鞭节的1.1和1.2倍。盾纵沟完整,伸及椭圆形的中陷;小盾片隆起,但未形成尖刺。回脉明显前叉式,小脉强烈后叉式。腹柄节长为其后端宽度的1.9倍。产卵器与腹部等长。 正模:♀,福建清流大丰山,1990-07-16,洪盛祥采集。 词源;本新种的种名“ustulatus”意指该新种的中胸背板红褐色。新种模式标本保存于福建农业大学益虫室。     

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...     

降香黄檀食叶害虫棕斑澳黄毒蛾的生物学特性及幼虫虫龄判断

【目的】棕斑澳黄毒蛾Orvasca subnotata Walker是于降香黄檀Dalbergia odorifera T. Chen人工林中新发现的一种食叶害虫,其生物学特性描述和龄期判定是虫害预测预报与林间防治的重要依据。【方法】本研究通过定期林间采样的方法,对棕斑澳黄毒蛾不同发育阶段的形态特征及生活史和生活习性进行调查; 并通过测量头宽、前胸毛瘤宽和体长3项分龄指标,测定棕斑澳黄毒蛾幼虫的龄期。【结果】本文报道了棕斑澳黄毒蛾不同发育阶段的形态特征、生活史和生活习性。研究结果表明,棕斑澳黄毒蛾幼虫随龄期增长,前胸逐渐变黑,腹部背线和翻缩腺颜色逐渐加深,特征逐渐变得明显。通过频次分析统计,测得棕斑澳黄毒蛾幼虫龄数为5龄。头宽和前胸毛瘤宽可作为分龄指标,头宽优于前胸毛瘤宽,且前胸毛瘤宽与头宽呈直线关系（y=0.994x-0.114,R=0.999）。体长经统计检验,符合Dyar氏法则,但区域重叠明显,不宜作为分龄指标。【结论】本研究确定了棕斑澳黄毒蛾的生物学特性及幼虫虫龄,可为林间防治提供参考依据。     

栗山天牛天敌花绒寄甲在栎林中的种群保持机制

花绒寄甲(Dastarcus helophoroides)(鞘翅目:寄甲科Bothrideridae)是寄生栗山天牛(Massicus raddei)中老龄幼虫和蛹的重要天敌,但其寄主栗山天牛世代周期长(3年1代)、发育比较整齐,不利于寄生性天敌种群数量的稳定.为了解利用花绒寄甲防治栗山天牛后,其种群能否在栎树林间长期保持较高的种群数量,达到持续控制栗山天牛的防治效果,调查研究了花绒寄甲在栎树林间的转主寄主和种群保持机制.结果表明,在东北辽东栎树干和树枝上除了栗山天牛外,还有其他8种天牛危害:双簇天牛(Moechotypa diphysis)、四点象天牛(Mesosa myops)、中华薄翅锯天牛(Megopis sinica)、锯天牛(Prionus insularis)、双带粒翅天牛(Lamiomimus gottschei)、八字绿虎天牛(Chlorophorus tohokensis)、日本绿虎天牛(C.japonicus)和拟蜡天牛(Stenygrinumquadrinotatum).其中以栗山天牛、双簇天牛、四点象天牛和拟蜡天牛数量较多,而花绒寄甲在辽东栎树干上的垂直分布与栗山天牛、双簇天牛和四点象天牛的垂直分布重叠较多.室内研究表明,花绒寄甲对四点象天牛老熟幼虫的寄生率达到26.67％,对蛹的寄生率达到了43.33％;对双簇天牛老熟幼虫的寄生率达到20.00％,对蛹的寄生率为6.67％.对双簇天牛和四点象天牛在林间的生活史调查和研究发现,花绒寄甲可寄生的这两种天牛的中老龄幼虫和蛹,在花绒寄甲不适宜寄生的栗山天牛幼龄幼虫期大量存在,表明双簇天牛和四点象天牛是花绒寄甲在栎树林中的主要转主寄主.由于这些转主寄主的存在,花绒寄甲在不利于其寄生的栗山天牛卵期、幼龄幼虫期可转移寄生这些寄主,从而在栗山天牛危害的栎树林间保持了较高的种群数量,达到对栗山天牛长期而有效的持续控制效果.     

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.     

An adaptive bivariate kernel smoothing method for determining instars of Austrosimulium tillyardianum (Diptera: Simuliidae) larvae

1. In insects, instar determination is generally based on the frequency distribution of sclerotised body part measurements. Commonly used univariate methods, such as histograms and univariate kernel smoothing, are not sufficient to reflect the distribution of the measurements, because development of sclerotised body parts is multidimensional. 2. This study used an adaptive bivariate kernel smoothing method, based on 10 pairs of separating variables, to differentiate instars of Austrosimulium tillyardianum (Diptera: Simuliidae) larvae in two‐dimensional space. A variable bandwidth matrix was used and separation lines between instars were defined. Using the Crosby growth ratio, Brooks' rule and the new standard recently proposed, larvae were separated into nine instars. It was found that, using the bivariate kernel smoothing method, the clustering accuracy and determination of separation lines as instar class limits were higher than those associated with the univariate kernel smoothing method. With the exceptions of the paired separating variables, head capsule length and antennal segment 3 length (AS3L), the mean probabilities of correct classifications was > 85%. The pair of separating variables that yielded the greatest classification accuracy comprised mandible length (ML) and AS3L, which had mean probabilities of 0.8984. The clustering accuracy was higher for early‐ and late‐instar larvae, but lower for instars 6 and 7. The adaptive bivariate kernel smoothing method was better than univariate methods for instar determination, especially in the detection of divisions between instars and identification of a larval instar.     

Influence of generation and photoperiod on larval development of Lobesia botrana (Lepidoptera: Tortricidae)

The influence of generation (under field conditions) and photoperiod (under laboratory conditions) on Lobesia botrana larvae development was studied. Some larvae were collected during three annual generations in two grape-growing areas of northeastern Italy, and others were individually reared in the laboratory from egg to pupa on an artificial diet under two different photoperiod conditions (respectively, daylight 16 h/d [long day {LD}] and 14 h/d [short day {SD}]). The mandible lengths of collected larvae were measured and the data analyzed morphometrically to determine the number of larval instars. In the laboratory study, the number of larval moultings, the mandible length of each instar, the development time from hatching larva to pupa, and the pupal weight were considered. The measurement of mandible lengths of larvae collected in the field indicated the existence of five larval instars in all three annual generations, but the size of the two oldest larval instars was significantly higher for third-generation larvae than for the previous generations. Under laboratory conditions, the larvae usually exhibited five instars, but the mandible lengths of larvae and the pupa size were greater for individuals reared under SD. These also took a greater number of days to develop from hatching larvae to pupae. Because a larger size of the final larval instar occurs in individuals that produce diapausing pupae under SD in both the laboratory and the field, a positive association between larval size and the probability of surviving the winter can be inferred.