龟纹瓢虫的捕食胁迫作用对连续三代果蝇发育与繁殖的影响

Effect of prey stress from Propylea japonica on development and fecundity of Drosophila melanogaster in successive three generations

捕食性天敌不仅直接捕食害虫,而且还能改变害虫的生长发育、繁殖,间接地影响害虫的适合度。以常见模式昆虫黑腹果蝇Drosophila melanogaster Meigen及捕食性天敌龟蚊瓢虫为研究系统,研究龟纹瓢虫Propylea japonica Thunberg连续多代直接捕食胁迫、一代捕食胁迫后下一代不捕食胁迫,对果蝇生长发育、繁殖和适合度的影响。结果表明:如果持续地释放瓢虫对果蝇的捕食胁迫作用,显著缩短了第1代、第2代果蝇的幼虫的发育历期,增加了第1代、第2代果蝇的繁殖量。但在第3代的影响却是延长了果蝇的幼虫的发育历期,降低第3代果蝇的繁殖量。如果在上一代胁迫作用得到释放后,下一代不再有瓢虫胁迫,那么连续2代胁迫后去掉胁迫的果蝇比只胁迫一代后去掉胁迫的果蝇幼虫的发育历期明显延长,繁殖量明显下降,后代性比也明显下降。与连续胁迫条件下的处理相比,成虫的寿命明显延长;对果蝇幼虫的发育历期、繁殖量则没有显著影响。结果表明,龟蚊瓢虫的干扰胁迫作用,可以间接的增加果蝇的适合度,促进果蝇种群的增长,使果蝇种群自我维持、调节到相应的水平。

The development and fecundity of Drosophila melanogaster Meigen,were examined as the response to the predator,Propylaea japonica Thunberg. The results showed that the developmental duration of larvae in the first and second generation decreased under continuous stress from ladybeetle,and the fecundity increased. However,the developmental duration of larvae increased and fecundity decreased in the third generation. When the prey stress disappeared,the developmental duration of larvae after two generations under prey stress was longer than that of larvae after one generation under prey stress,and the fecundity and sexual ratio significantly decreased. In comparison with those under continuous stress,the longevity of adults significantly increased,whereas there was no difference in the fecundity and developmental duration of larvae. It revealed that the stress of P. japonica could indirectly increase the fitness of D. melanogaster,and promote population growth,which led to auto-regulation of D. melanogaster population.