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、0.71...

Measurement of larval instars and stadia of Stenocephus fraxini larva

In order to determine the number of larval instars and stadia of Stenocephus fraxini, the body length, head width, body width (3rd segment of thorax), forceps length and forceps basal width of the larva of S. fraxini were measured. According to the frequency distribution and regression analysis, the results showed that the larvae of S. fraxini had 5 instars. The head width and forceps basal width can be variable for the distinguishment of larval instars. The head width of each instars larvae were 0.414 ± 0.002, 0.526 ± 0.002, 0.713 ± 0.005, 1.003 ± 0.006 and 1.398 ± 0.010, respectively, and their forceps basal width were 0.060 ± 0.001, 0.095 ± 0.001, 0.150 ± 0.002, 0.231 ± 0.002 and 0.344 ± 0.005, respectively. The average stadia of 1-5 instar were 2.5, 3.5, 5, 8 and 40 d, respectively. The development duration of the larva of S. fraxini was about 50-70 d, with an average of 60 d.