黄脊雷蓖蝗生物学特性及若虫各龄期雌雄的区分

Biological characteristics of Rammeacris kiangsu Tsai and distinction between female and male nymphs in different instars

黄脊雷蓖蝗Rammeacris kiangsu Tsai是我国的重要森林害虫,给竹业生产造成严重的危害。对黄脊雷蓖蝗重庆永昌、四川长宁、湖南桃江及广西桂林种群若虫发育历期、若虫各龄期虫体大小、若虫各龄期外生殖器形态特征及成虫产卵前期等进行了调查,以期为黄脊雷蓖蝗的虫情调查和预测预报提供基础数据。结果表明,在25℃的实验室条件下,4种群的雌、雄若虫发育历期分别介于68.3～73.6 d和60.8～64.2 d,种群间雌若虫和雄若虫的发育历期均无显著差异。雄若虫均为5龄,而雌若虫则为部分5龄、部分6龄,永昌、长宁、桃江和桂林种群6龄雌若虫所占比例分别为55.6%、40.0%、27.3%和17.0%。第1～4龄若虫各龄期发育历期介于10～13 d,第5龄若虫的发育历期略长,为17 d左右,第6龄雌若虫的发育历期亦较长,达17 d以上。重庆永昌、四川长宁和湖南桃江种群成虫的产卵前均在35 d前后,而纬度较低的广西桂林种群达50 d以上。同时,对各龄期雌、雄若虫的外生殖器形态特征进行了观察,依据外生殖器形态可对若虫各龄期及不同龄期雌、雄若虫进行区分,结合本研究测量的各龄期若虫头幅、后足腿节长等数据,可为黄脊雷蓖蝗的虫情调查和预测预报提供参考。

Rammeacris kiangsu Tsai is an important forest pest in China,and causes serious harm to bamboo production.To provide basic data for investigation and forecasting of occurrence,the development period,body size and characteristics of external genitalia of nymphs in different instars,and the pre-oviposition period of adults in R.kiangsu collected from Yongchang,Changnin,Taojiang,and Guilin were investigated.The results show that the developmental period of female and male nymphs were 68.3～73.6 days and 60.8～64.2 days respectively at 25 ℃.There were no significant differences both in female and male nymphs among the four populations.All male nymphs had five instars,but some of the female nymphs had five instars and some had six instars.The percent of nymphs that had six instars was 55.6 %,40.0 %,27.3 % and 17.0 % in Yongchang,Changning,Taojiang,and Guilin population,respectively.The developmental period of nymphs within 1～4th instars were 10～13 days respectively,the period of the 5th instars was about 17 days,and that of the 6th instars was more than 17 days.The pre-ovipositional periods of adult females in Yongchang,Changning,and Taojiang populations were about 35 days,but that of adults in the Guilin population was longer than 50 days.Meanwhile,the observation of nymphal external genitalia in different instars showed that the instars and sex of nymphs could be distinguished by the characteristics of the genitalia.Combined with the data collected from head width and femur length of hind leg of nymphs in different instars,the findings could provide reference for investigation and forecasting of occurrence.