【摘要】 马尾松毛虫Dendrolimus punctatus Walker是南方林业重大害虫,目前对其在高海拔区(>700 m)的发生特点仍不清楚。本研究从湖南绥宁(26.35°N,110.09°E)高海拔区采虫,放在5个光周期处理下饲养,以年龄-时期、两性生命表法计算种群参数,揭示光周期对该种群发生的影响。结果显示:L∶D=15.5∶8.5(15.5 h)和L∶D=14.5∶9.5(14.5 h)光周期处理组种群发生正常,而L∶D=11.5∶12.5(11.5 h)、L∶D=12.5∶11.5(12.5 h)和L∶D=13.5∶10.5(13.5 h)光周期处理组未观察到成虫发生。15.5 h组内禀增长率(r)为0.057 d-1,净生殖力(R0)为55.73粒,单雌产卵力(fecundity)为241.5粒,平均世代时间T为71.05 d,14.5 h组r为0.018 d-1,R0为6.29粒,显著低于15.5 h组。该种群在14.5 h光周期处理下表现出分散繁殖行为,即出现两个繁殖期,时差1个月左右。与15.5 h处理组相比,14.5 h处理组成虫寿命显著缩短。该研究表明:马尾松毛虫高海拔种群对光周期变化响应强烈,而湖南绥宁光周期在7月底就开始变短,当地马尾松毛虫在这种光周期诱导下较早进入滞育发育,因而种群年发生仅一代。更多还原

【Abstract】 Dendrolimus punctutas Walker is a key forest pest in South China,but its occurrence athigh altitudes( > 700 m) is still unknown. We collected samples of D. punctutas at the high altitude site of Suining( 26. 35°N,110. 09° E). These samples were subjected to five successive photoperiods in the laboratory,with the aim of investigating the influence of photoperiod on population parameters,which were computed for different age-stages and by compiling two-sex life tables. The results show that entire captive population went into diapause at L∶D = 15. 5∶8. 5( 15. 5 h) and L∶ D = 14. 5∶9. 5( 14. 5 h),but only partly at L∶ D = 11. 5∶12. 5( 11. 5 h),L∶D = 12. 5∶11. 5( 12. 5 h) and L∶ D = 13. 5 ∶10. 5( 13. 5 h). Population parameters were calculated as 0. 057 d- 1intrinsic rate of increase( r),net reproductive rate( R 0) of 55. 73,fecundity of 241. 5/female and 71. 05 d mean generation time( T) at 15. 5 h. r and R 0 were significantly higher than 0. 018 d- 1and 6. 29 at 14. 5 h. Dispersive breeding behavior was observed at 14. 5 h because reproduction peaked at two separate times,with the second time lagging almost one month. Adults at 14. 5 h showed reduced longevity compared with those at 15. 5 h. These results suggest that the response to photoperiod change is intensified in high altitude populations,and that D. punctutas is induced into early diapause by a decrease of photoperiod after the end of July in Suining. It therefore possibly produces just one generation there annually.更多还原