幼虫密度对马铃薯块茎蛾生长发育及繁殖的影响

室内观察了块茎中不同虫口密度(5、10、15、20、25、30头/块茎)对马铃薯块茎蛾Phthorimaea operculella(Zeller)生长发育、后代发育和繁殖的影响。结果显示:幼虫密度显著影响马铃薯块茎蛾的生长发育及繁殖。对其生长发育影响的结果表明:幼虫的发育历期(7.1～9.1d)、蛹的历期(8.8～9.9d)、雌雄成虫的历期(分别为6.4～12.9d,6.7～11.6d)随幼虫密度的增加而延长;幼虫存活率(70.3%～93.3%)、蛹的羽化率(69.8%～91.7%)随幼虫密度的增加显著下降;单头蛹重(9.2～11.4mg)、单雌产卵量(136.8～166.0粒)、成虫的雌∶雄比(0.54～2.17)随幼虫密度的增加而下降。对其后代发育及繁殖的影响的结果表明:卵的发育历期(3.0～4.4d)、幼虫的发育历期(6.2～10.8d)、蛹的历期(8.1～10.0d)、雌雄成虫的历期(分别为7.4～11.8d,6.6～10.5d)、世代发育历期(24.4～36.1d)随幼虫密度的增加而从延长;卵的孵化率(73.1%～79.0%)、幼虫存活率(55.0%～96.8%)、蛹的羽化率(63.3%～93.3%)、世代的存活率(25.6%～71.5%)随虫口密度的增加而下降;单头蛹重(8.9～9.9mg)、单雌产卵量(93.5～155.6粒)、成虫的雌∶雄比(0.45～2.20)随虫口密度的增加而下降;种群趋势指数(I)(7.44～76.43)随幼虫密度的增加而下降。马铃薯块茎蛾的饲养密度建议以1头/13.0～26.0g块茎为宜。

Effect of larval density on growth, development and reproduction of potato tuber moth, Phthorimaea operculella

The effect of larval density （5,10,15,20,25 and 30 larvae /tuber） on the growth,development and reproduction of offspring of the potato tuber moth Phthorimaea operculella Zeller was investigated under laboratory conditions. The results show that larval density significantly affected growth,development and reproduction. The duration of larval （7. 1 - 9. 1 d）,and pupal （8. 8 - 9. 9 d） stages,and adult female and male life spans （6. 7 - 11. 6 d,6. 4 - 12. 9 d,respectively）,was longer at higher larval densities. Larval survival （70. 3% - 93. 3% ） and pupal emergence （69. 8% - 91. 7% ） were significantly lower at higher larval densities. Pupal weight （9. 2 - 11. 4 mg）,the number of eggs per female （136. 8 - 166. 0） and the ratio of females∶ males （0. 54 - 2. 17） decreased with increasing larval density. Increased larval density also affected the life history of offspring; offspring of insects raised at high larval densities had longer egg （3. 0 - 4. 4 d）, larval （6. 2 - 10. 8 d）,pupal （8. 1 - 10. 0 d）,and adult stages （female = 7. 4 - 11. 8 d,male = 6. 6 - 10. 5 d）,and a longer overall generation time （ 24. 4 - 36. 1 d）. However,they also had lower hatching （73. 1% - 79. 0% ）,larval survival （55. 0% - 96. 8% ）,pupal emergence （63. 3% - 93. 3% ） and overall survival （25. 6% - 75. 1% ）. The offspring of insects raised at high larval densities had lighter pupae （8. 9 - 9. 9 mg）,a lower female∶ male ratio （0. 45 - 2. 20） and fewer eggs per female （93. 5 - 155. 6）. The index of population trend （ Ⅰ） decreased from 76. 43 - 7. 44 with increasing larval density. The optimal density of potato tuber moths was 1 larvae / 13. 0 - 26. 0 g tuber.