花绒寄甲幼虫调控寄主松褐天牛幼虫免疫系统的生理机制

Dastarcus helophoroides Fairmaire is the most important parasitic natural enemy of Monochamus alternatus Hope, the primary vector of pine wilt disease, and is of great significance in control of this important pest. To explore the parasitic mechanism of D. helophoroides to M. alternatus, the project select D. helophoroides larvae and M. alternatus as the research object. M. alternatus larvae are inoculated with D. helophoroides larvae to explore the impact of parasitization of D. helophoroides larvae on the immune system in M. alternatus larvae. We measure the indicators about cellular immunity and humoral immunity in M. alternatus larvae, including hemocyte counts, cell spreading and encapsulation, hemolymph phenoloxidase activity, melanization, agglutination and antimicrobial effect, after parasitization. At the same time, we study the variation and relationship of the indicators above. The purport is to analyze the physiological mechanism of the regulation of immune system in M. alternatus larvae by D. helophoroides larvae, in order to provide theoretical foundation for explaining the parasitic mechanism of D. helophoroides to M. alternatus, and further improving the biological control effect of D. helophoroides.

花绒寄甲是松褐天牛最主要的寄生性天敌，在控制这种重要害虫进而防治由其传播的松材线虫病上具有重要意义。为了探索花绒寄甲寄生松褐天牛的机理，本项目以花绒寄甲幼虫和寄主松褐天牛幼虫为研究对象，采用松褐天牛幼虫人工接种花绒寄甲幼虫的方法，探索花绒寄甲幼虫寄生对寄主松褐天牛幼虫免疫系统的影响。分别于花绒寄甲幼虫寄生寄主松褐天牛幼虫后不同时间，对寄主细胞免疫和体液免疫各项指标进行测定，包括血细胞数量、延展行为、吞噬作用，以及血淋巴酚氧化酶活性、黑化反应、凝集作用、抑菌作用，探索其变化规律及相互关系。其意义是要解析花绒寄甲幼虫调控寄主松褐天牛幼虫免疫系统的生理机制，为明确花绒寄甲寄生松褐天牛的机理，及进一步完善和提高花绒寄甲的生物防治效果，提供理论依据。

花绒寄甲是松褐天牛的一种外寄生型天敌，为了明确花绒寄甲寄生对其寄主松褐天牛幼虫免疫反应的影响，测定了寄主在被寄生后1、2、4、8、12、24、48、72h，血淋巴的黑化作用、凝集作用、酚氧化酶活性、抗菌活性，以及血细胞的数量、延展作用、结节作用。结果显示：花绒寄甲寄生对松褐天牛幼虫的免疫反应有明显的影响；寄主血淋巴黑化反应在寄生后1 h和24 h，明显被抑制；寄主血淋巴酚氧化酶活性在寄生后4 h显著升高，寄生后12 h 显著降低，之后又恢复到对照的水平；寄主血淋巴抗菌活性在寄生后1 h显著低于对照；寄主血细胞总数在寄生后72 h低于对照的1/2；寄主血细胞在寄生后的各个时间点，都具有结节作用能力，并且血细胞形成的结节数量波动很大；然而，寄主血淋巴的凝集作用以及血细胞中延展细胞的比例，并未受到寄生的影响。这些研究结果表明，花绒寄甲幼虫可以调控其寄主松褐天牛幼虫的免疫系统，从而导致寄主免疫反应的变化。