悬铃木方翅网蝽若虫龄数的测定

Determination of Nymph Instars of Corythucha ciliata(Say)

为提供悬铃木方翅网蝽测报、科学防治基础数据,本研究通过野外采集不同发育状态的悬铃木方翅网蝽若虫,测量若虫头壳宽、复眼宽、前胸背板宽、体宽及体长5种形态指标,制作频次分布图判断若虫龄数,运用Dyar法则、Brooks指数和Crosby指数确定分龄依据,使用回归分析进行验证。结果表明:前胸背板宽、体宽、体长Crosby指数不符合正确的分龄标准,故不适合为分龄依据;头壳宽、复眼宽各龄Crosby指数均小于10%,其中头壳宽Crosby指数最小,故头壳宽为悬铃木方翅网蝽若虫最佳分龄依据,复眼宽为次要分龄依据,若虫共划分为5龄,各龄若虫头壳宽均值为0.1540±0.0022mm、0.1965±0.0016mm、0.2314±0.0011mm、0.2699±0.0009mm和0.3033±0.0007mm,分龄指标头壳宽(y)与龄数(x)的二次回归方程为y=23.373x^(2)+5.459x-2.680(R^(2)=0.954)。

To provide the basic data of forecasting and control agaist Corythucha ciliata,we collected the nymphs of C.ciliata with different developmental status in the field,and measured five morphological indexes of the nymphs,including head capsule width,compound eye width,pronotum width,body width and body length.The frequency distribution map was made to determine the nymph instars.The Dyar rule,Brooks index and Crosby index were used to determine the basis of instar,and verify with the regression analysis.The results showed that the Crosby index of pronotum width,body width and body length couldn’t meet instar division standard,so it was not suitable for instar division.The Crosby index of head capsule width and compound eye width was less than 10%,and the Crosby index of the head capsule width was the smallest.Therefore,the head capsule width was the best instar division basis for the nymphs of C.ciliata,and then followed by the compound eye width.The nymphs were divided into 5 instars,and the average head capsule width of each instar was 0.1540±0.0022 mm,0.1965±0.0016 mm,0.2314±0.0011 mm,0.2699±0.0009 mm and 0.3033±0.0007 mm.The quadratic regression equation of the instar index head capsule width(y)and instar number(x)was y=23.373x^(2)+5.459x-2.680(R^(2)=0.954).