双条杉天牛不同虫期体壁碳氢化合物变化规律分析

目的]研究双条杉天牛幼虫期和成虫期体壁碳氢化合物的变化规律,对不同虫期体壁碳氢化合物成分、含量和比例进行分析,期望在此基础上探索体壁碳氢化合物在其生殖行为中的功能。方法]采用固相微萃取和溶剂浸提两种采样方法收集双条杉天牛不同虫期的体壁碳氢化合物成分,进一步采用气相色谱-质谱联用仪(GC-MS)对提取物进行分析,比较不同成分在不同虫期的含量和比例。结果]双条杉天牛体壁碳氢化合物成分主要包括C15-C31之间的正烷桂、烯桂、单甲基支链烷桂和二甲基支链烷桂。幼虫体壁碳氢化合物以C15~C31正烷桂为主,含量占64.67%,其中n-C27含量最高(21.57%);烯桂仅检测到角鲨烯,含量占19.4%;甲基支链烷桂仅检测到3Me-C25和11,15diMe-C27,含量占15.93%。在刚羽化的雌成虫中正烷桂占60.42%,甲基支链烷桂占39.58%;雄成虫中正烷桂占74.15%,甲基支链烷桂占25.85%。扬飞期雌成虫中正烷桂占53.13%,甲基支链烷桂占46.87%;雄成虫中正烷桂占45.99%,甲基支链烷桂占54.01%;雌雄成虫中均是n-C25含量最高。随着虫体的发育,正烷桂含量呈下降趋势,而甲基支链烷桂呈上升趋势。溶剂浸提法和固相微萃取法提取的体壁碳氢化合物有相似的变化趋势。结论]双条杉天牛不同虫期体壁碳氢化合物各种成分含量的变化与其发育的性成熟度有关。幼虫体壁中未检测到11Me-C26,11Me-C27和3Me-C27,这3种成分在雌雄成虫中含量差异显著,推测其可能在成虫生殖行为中扮演重要角色,这为进一步研究双条杉天牛接触性识别信息素奠定良好基础。

Changes of Cuticular Hydrocarbons of Semanotus bifasciatus Motschulsky in Different Developmental Stages

Objective]To study the change of the cuticular hydrocarbons(CHCs)of larvae and adult of Semanotus bifasciatus and their potential reproductive functions between males and females by analyzing the components,contents,and ratios of CHCs of S.bifasciatus in different developmental stages.Method]The CHCs extracted from different developmental stages of S.bifasciatus by hexane solvent and solid phase microextraction(SPME)methods were analyzed by means of gas chromatography(GC)coupled with mass spectrometer(MS),and comparative analysis of the contents and ratios of CHCs were conducted.Result]GC-MS analysis of the CHCs from different developmental stages of Sbifasciatus demonstrated the presence of four homologous series of alkanes:n-alkanes from C15 to C31,alkenes,monomethylalkanes,and dimethylalkanes.Of the total hydrocarbons in the body wall of the mature larvae,the n-alkane series from C15 to C31 accounted for 64.67%,with the major component being n-heptacosane(abundance:21.57%);Squalene was the only detected alkene with 19.4%proportion in the CHCs;of the methylalkanes,it was 3-methylpentacosane and 11,15-dimethylheptacosane accounting for 15.93%.The n-alkane series accounted for 60.42%of the total hydrocarbons in newly emerged females,74.15%in newly emerged males,53.13%in flying stage females,and 45.99%in flying stage males.In the branched-chain series,the newly emerged female elytra accounted for 39.58%,the newly emerged male elytra for 25.85%,the flying stage female elytra for 46.87%,and the flying stage male elytra for 54.01%of the total hydrocarbons.The n-pentacosane was the highest abundance in male and female adults.With the development of S.bifasciatus from larvae to adult,the contents of nalkanes showed a decreasing trend and the methyl-branched alkanes showed an increasing trend.The change of CHCs from solvent extracts showed the same trends as the SPME sampling method.Conclusion]The change of compositions and contents of CHCs from different stages of Sbifasciatus is related to its developmental sexual maturity stages.11Me-C26911Me-C27,and 3Me-C27 were not detected in the larval body wall,however,they showed significant differences in female and male elytra.It is speculated that these three compounds play important roles in reproductive behaviors of adults.