两种复壮方法对昆虫病原线虫致病力、生殖力、存活能力的影响

Comparison of two rejuvenation methods on the virulence, fecundity and viability of Heterorhabditis megidis and Steinernema felitiae

【目的】为探明不同复壮方法对昆虫病原线虫致病力、生殖力等的影响。【方法】选用韭蛆BradysiaodoriphagaYangetZhang和大蜡螟Galleriamellonella2种寄主昆虫复壮异小杆线虫Heterorhabditis megidis0627M和斯氏线虫Steinernema felitiae0619HT,复壮后测定2种品系线虫的致病力、生殖力、死亡率,并观察线虫寄生后2种寄主的行为、体色的变化情况及引起寄主死亡时间。【结果】不同复壮方法对2种品系线虫存活能力的影响不同。短时间保存10 d时,2种复壮方法下2种品系的线虫死亡率都很低,且随保存时间递增,死亡率均有上升;保存30 d时,经韭蛆复壮的S. felitiae 0619HT的死亡率高于H. megidis0627M品系的,而经大蜡螟复壮的H. megidis 0627M和S. felitiae 0619HT的死亡率相差不大;韭蛆复壮后的昆虫病原线虫致病力较高;保存40 h时,H. megidis 0627M和S. felitiae 0619HT对大蜡螟的致死率均为100%,侵入率分别为5.67%和2.33%,均低于用大蜡螟复壮的线虫;韭蛆复壮后2种品系的生殖力高于大蜡螟复壮的且差异显著,用韭蛆复壮后H.megidis0627M和S.felitiae0619HT的生殖力分别为1.4613×10^(5)头/g和2.395 2×10^(5)头/g,均高于用大蜡螟复壮的生殖力。【结论】与大蜡螟相比,用寄主韭蛆复壮异小杆线虫和斯氏线虫是比较好的复壮方法,H. megidis 0627M和S. felitiae 0619HT两种品系可以通过寄主韭蛆复壮使其生殖力、致病力和侵入率都明显升高,更有利于后期线虫的非生物胁迫提供基础。因此,室内复壮昆虫病原线虫时,可采用寄主昆虫回归复壮。

[Objectives] To investigate the effects of different rejuvenation methods on the pathogenicity and fecundity of the entomopathogenic nematodes Heterorhabditis megidis 0627 M and Steinernema felitiae 0619 HT. [Methods] The pathogenicity, fecundity and mortality of H. megidis 0627 M and S. felitiae 0619 HT with respect to two different host species Bradysia Odoriphaga Yang et Zhang and Galleria mellonella was measured and compared. Changes in host behavior, body color and time to death of both species were also observed. [Results] Different methods of rejuvenation had different effects on nematode survival. Mortality of both strains was very low when they had been stored for a short time(10 d) but increased with increased duration of storage. Mortality of S. felitiae 0619 HT was higher, but not significantly so, than that of H. megidis 0627 M. The pathogenicity of both H. megidis 0627 M and S. felitiae 0619 HT to Mellonella mellonella was 100% after 40 h,and the infection rate was 5.67% and 2.33%, respectively. The fecundity of H. megidis 0627 M was 1.461 3×10^(5) individuals/g whereas that of S. felitiae 0619 HT was 2.395 2×10^(5) individuals/g, respectively, higher than that of S. mellonella. [Conclusion]It is preferable to reinvigorate H. megidis 0627 M and S. felitiae 0619 HT by reinvigorating their hosts, which significantly increased the fecundity, pathogenicity and infection rates of both species.