低湿胁迫对昆虫病原线虫生物学特性的影响

Effects of anhydrobiosis on entomopathogenic nematode and its biological characteristics

以8种甘肃省优势种昆虫病原线虫为研究对象,采用室内模拟生测法,测定了低湿胁迫对昆虫病原线虫存活率、致病力及生殖力的影响。结果表明:在25℃、相对湿度50.5%分别处理5,7和9 h后,供试的斯氏属线虫仍具有较高的存活率,而异小杆属线虫存活率减低;经低湿处理9 h后再复苏,5种斯氏线虫侵染大蜡螟48 h后,Steinernema feltiae0619HT、S.bicornutum0631PG、S.kraussei0657L、S.karii0663YC对大蜡螟的致病力均为100%,与对照组差异不显著(P>0.05),而S.affine 0619M为75%,差异显著(P<0.05);5种线虫侵入率较对照组均下降,S.bicornutum0631PG、S.affine 0619M、S.kraussei0657L较高,均高于16%,与S.karii0663YC差异显著(P<0.05);低湿胁迫后S.felitiae0619HT和Heterorhabditismegidis0627M的生殖力无显著变化。试验表明,不同种类昆虫病原线虫在低湿胁迫的影响下其生物学特性,异小杆线虫抗低湿胁迫能力较斯氏线虫弱,其中S.kraussei0657L抗低湿胁迫能力最强;低湿胁迫能使昆虫病原线虫的侵入率降低,但是对其致病力无显著影响;且低湿胁迫对S.felitiae0619HT和H.megidis0627M的生殖力无显著影响。

The anhydrobiosis and 8 species of entomopathogenic nematodes from Gansu Province,including 5 species of Steinernema(S.feltiae 0619 HT,S.bicornutum 0631 PG,S.kraussei 0657 L,S.karii 0663 YC and S.affine 0619 M) and 3 species of Heterorhabditis(H.megidis 0627 M,H.brevicaudis 0641 TY and H.marelatu 0639 G),were used to study the impact of low humidity on the survival rate,pathogenicity and fertility of the nematodes.The results showed that Steinernema spp.still kept high survival rate under the conditions of 50.5% humidity and 25℃ for 7 and 9 hours,but it was lower for Heterorhabditis spp.After the low humidity stress treatment for 9 hours and recovery,the pathogenicity of infective juveniles(IJs) of 4 species from Steinernema(S.feltiae 0619 HT,S.bicornutum 0631 PG,S.kraussei 0657 L,S.karii 0663 YC) were 100%,and no significant difference with the control(P>0.05),and as for S.affine 0619 M,it was 75%(P<0.05).The invasion rate of all 5 species was lower than control.And there was no significant difference in the fecundity of S.felitiae 0619 HT and H.megidis 0627 M after low humidity stress.The resistance of Steinernema to low humidity stress was stronger than that of Heterorhabditis,especially S.kraussei 0657 L.Low humidity stress reduced the infection rate of entomopathogenic nematodes,but no significant influence on their pathogenicity.Moreover,the low humidity stress had no significant effect on the fertility of S.felitiae 0619 HT and H.megidis 0627 M.