甜菜夜蛾虫酰肼抗性品系选育及相对适合度研究

本试验在室内对甜菜夜蛾Spodoptera exigua(Hübner)武汉敏感品系进行了8代群体汰选后分别于9、10、12代采用了单对汰选。结果表明虫酰肼处理后各单对品系后代幼虫存活率发生明显分离,F9(s1)、F10(s2)和F12(s3)代幼虫平均存活率分别为48.34%、11.72%和2.37%,筛选后分别为84.00%、83.33%和7.29%。经过12代汰选后,汰选品系抗性倍数为敏感品系的5.24倍,且单对汰选世代对虫酰肼的抗性发展较快,其抗性倍数分别是群体汰选的1.27、1.67和1.38倍。比较单对汰选世代与群体汰选世代某些生物学特性,显示单对汰选世代并不存在生长发育和生殖不利性,表明在虫酰肼群体汰选中穿插几代单对汰选可以加速抗性品系的选育。汰选品系相对于敏感品系具有0.31的适合度,表明甜菜夜蛾对虫酰肼产生抗性后存在适合度缺陷。

Selection of Spodoptera exigua for tebufenozide resitance and relative fitness of the resultant resistant strain

A Wuhan-susceptible strain of Spodoptera exigua （Hiibner） was selected for in the laboratory through 12 generations of selective breeding, using mass selection, alternating with single selection in the 9th, 10th and 12th generations. We found that survival rates of S. exigua larvae from different single pair families after treatment with tebufenozide were significantly different. Average survival rates were 48.34% , 11.72% , 2.37% respectively in F9（a1） , F10（a2） and F12（,3） , compared with 84. 00% , 83.33% and 7.29% respectively in selected single pair families. After selection for 12 generations by mass and single selection, the selected strain showed a 5.24-fold increase in resistance to tebufenozide compared with the susceptible strain. Resistance of single selected generations increased faster than that of mass selected generations, the increases of the former being 1.27, 1.67, 1.38 times, respectively, that of the latter. In comparisons of some biological parameters between mass and single selected generations of S. exigua, the single selected generations did not display developmental or reproductive disadvantages. The speed of development of resistance selection was increased by alternating a few generations of single pair selection in the mass-selected population. The selected strain had a fitness of 0. 31 relative to the susceptible strain. This indicates that the development of tebufenozide-resistanee in S. exigua has a fitness cost.