Scott K D, Wilkinson K S, Lawrence N, Lange C L, Scott L J, Merritt M A, Lowe A J, Graham G C
School of Integrative Biology, The University of Queensland, Brisbane, Qld 4072, Australia.
Bull Entomol Res. 2005 Aug;95(4):381-92. doi: 10.1079/ber2005369.
Both large and small scale migrations of Helicoverpa armigera Hübner in Australia were investigated using AMOVA analysis and genetic assignment tests. Five microsatellite loci were screened across 3142 individuals from 16 localities in eight major cotton and grain growing regions within Australia, over a 38-month period (November 1999 to January 2003). From November 1999 to March 2001 relatively low levels of migration were characterized between growing regions. Substantially higher than average gene-flow rates and limited differentiation between cropping regions characterized the period from April 2001 to March 2002. A reduced migration rate in the year from April 2002 to March 2003 resulted in significant genetic structuring between cropping regions. This differentiation was established within two or three generations. Genetic drift alone is unlikely to drive genetic differentiation over such a small number of generations, unless it is accompanied by extreme bottlenecks and/or selection. Helicoverpa armigera in Australia demonstrated isolation by distance, so immigration into cropping regions is more likely to come from nearby regions than from afar. This effect was most pronounced in years with limited migration. However, there is evidence of long distance dispersal events in periods of high migration (April 2001-March 2002). The implications of highly variable migration patterns for resistance management are considered.
利用分子变异分析（AMOVA）和基因分配测试，对澳大利亚棉铃虫（Helicoverpa armigera Hübner）的大规模和小规模迁飞进行了研究。在38个月的时间里（1999年11月至2003年1月），从澳大利亚八个主要棉花和谷物种植区的16个地点采集了3142个个体，筛选了五个微卫星位点。1999年11月至2001年3月期间，种植区之间的迁飞水平相对较低。2001年4月至2002年3月期间，基因流速率显著高于平均水平，种植区之间的分化有限。2002年4月至2003年3月这一年中，迁飞率降低，导致种植区之间出现显著的遗传结构。这种分化在两到三代内就已形成。仅靠遗传漂变不太可能在如此少的世代中导致遗传分化，除非同时伴有极端瓶颈效应和/或选择作用。澳大利亚的棉铃虫表现出距离隔离现象，因此迁入种植区的个体更有可能来自附近地区而非远方。这种效应在迁飞有限的年份最为明显。然而，在迁飞高发期（2001年4月至2002年3月）有远距离扩散事件的证据。文中还考虑了高度可变的迁飞模式对抗性管理的影响。
