德国小蠊若虫龄期区别的体征研究

Study on physical characteristics of Blattella germanica in different nymphal instars

目的通过观察德国小蠊的蜕皮现象确定其发育龄期,以获取不同发育阶段的德国小蠊体征与龄期相关信息,为德国小蠊实验室研究和现场工作的龄期判断以及德国小蠊实验与研究的标准化提供依据。方法取德国小蠊的单卵荚进行饲养,逐日观察并记录其蜕皮和龄期发育情况,测定各龄期若虫的头宽、体长和体重等身体特征,通过统计分析各龄期的主要体征值来确定若虫龄期。结果在饲养条件下,德国小蠊若虫共经历6个龄期,各龄历期分别为(13.00±1.29)、(11.17±1.17)、(12.33±2.07)、(10.20±1.10)、(10.50±1.05)和(9.50±1.05)d,各龄历期间差异无统计学意义;1～6龄若虫的头宽分别为(0.99±0.16)、(1.03±0.15)、(1.62±0.19)、(1.83±0.22)、(2.02±0.21)和(2.05±0.22)mm;体长分别为(3.69±0.35)、(5.27±0.57)、(7.03±0.70)、(9.48±0.67)、(11.19±0.61)和(11.48±0.44)mm;体重分别为(2.39±0.11)、(8.70±0.69)、(17.64±5.27)、(37.97±5.04)、(50.66±9.23)和(66.20±11.60)mg/只;德国小蠊的龄期与头宽、体长或体重间呈显著正相关,相关系数(r)分别为0.9539、0.9854和0.9879。结论在相对稳定的条件下,德国小蠊不同龄期间的体重变化最明显,其次是体长;可根据体重、体长和头宽,对个体的龄期进行综合判断。

Objective To determine the nymphal instar of Blattella germanica by observing its ecdysis and acquire the physical characteristics of B. germanica in different nymphal instars, and to provide a basis for judging the nymphal instar of B. germanica in the field work and laboratory study and standardizing the experimental study of B. germanica. Methods Egg capsules were collected from female adults of B. germanica and then hatched to obtain nymphs. The nymphs were fed, and their ecdysis and instars were observed and recorded every day. The head width, body length, and body weight of the B. germanica in each nymphal instar were measured to statistically analyse the correlation between the nymphal instar and these physical characteristics. Results In the laboratory, the nymph ofB. germanica went through six instars, with durations of （13.00± 1.29）, （11.17 ± 1.17）, （12.33 ± 2.07）, （10.20 ± 1.10）, （10.50 ± 1.05）, and （9.50 ± 1.05） days, respectively, and there were no significant differences among the instars. From the first to the sixth instar, the head widths were （0.99± 0. 16）, （1.03 ±0. 15）, （1.62±0.19）, （1.83±0.22）, （2.02 ± 0.21）, and （2.05 ± 0.22） mm, respectively; the body lengths were （3.69 ± 0.35）, （5.27 ± 0.57）, （7.03 ± 0.70）, （9.48 ± 0.67）, （11.19 ± 0.61）, and （11.48 ± 0.44） mm, respectively; the body weights were （2.39 ± 0.11）, （8.70 ± 0.69）, （17.64 ± 5.27）, （37.97 ± 5.04）, （50.66 ± 9.23）, and （66.20 ± 11.60） mg, respectively. There was a significant positive correlation of the nymphal instar of B. germanica with the head width, body length, and body weight （r=0.9539, 0.9854, and 0.9879）. Conclusion Under the relatively stable conditions, the B. germanica in different nymphal instars shows the most significant change in body weight, followed by body length, so the nymphal instar of B. germanica can be judged by its body weight, body length, and head width.