Data from: Stay at home aphids: comparative spatial and seasonal metapopulation structure and dynamics of two specialist tansy aphid species studied using microsatellite markers

Two tansy-feeding aphids – Macrosiphoniella tanacetaria (MA) and Metopeurum fuscoviride (ME) – were studied at a small spatial scale in and around Jena (< 80 km2) using polymorphic microsatellite markers. Both species were found in ~ 60% of sites formerly known to harbour the aphids, although generally when they did occur, they occurred singly (MA ~ 50%; ME ~60%) and rarely together on the same plant at the same time (~10%) and then usually only in the early part of the growing season. This difference may be due to quasi-apparent competition effects elicited to ants farming ME aphids, and preferentially actively eliminating or disturbing MA aphids. In terms of population genetics, both aphids showed extreme genetic heterogeneity within a metapopulation structure, ME more than MA, i.e. higher FST values, ~ 0.4 vs. 0.15, respectively, and limited levels of interpopulation gene flow. Subpopulations often deviated from Hardy-Weinberg equilibrium and showed linkage disequilibria, as expected in animals with extended parthenogenetic reproduction, and had positive FIS values for most large samples, suggesting inbreeding, and possibly philopatry, certainly in ME. Hierarchical analysis (allele range and number per locus, analysis of molecular variance and FST) strongly suggested that the plant rather than site governs the level of genetic variation. Bayesian clustering analysis revealed that both species had heterogeneous historical genetic patterning, with K (number of subgroups) ranging from 3-7. Evidence is also provided from isolation by distance (IBD) and private allele analyses, that in MA, the presence of winged autumn males, absent in ME where males are wingless, influences comparative population genetic structuring, such that ME subpopulations are comparatively more inbred and genetically differentiated than MA subpopulations. Lastly, additional spatial arrangement (ALLELES-IN-SPACE) analysis showed that in both species, certain subpopulations were genetically isolated from the remainder, probably due to geographical barriers, including intervening buildings and woods. As such, the biology of these tansy aphids living in semi-natural habitats is very different from many pest aphid species examined within agro-ecosystems and infesting ephemeral crops, since the former seem much more reluctant to fly and hence show contrastingly much higher levels of interpopulation divergence, even at small spatial scales as here investigated. Indeed, the number of genotypic clusters found for tansy aphids found using Bayesian approaches is similar to that for the major pest the peach-potato aphid, Myzus persicae, globally.

以耶拿市及周边区域（面积小于80平方千米）为研究范围，在小空间尺度下利用多态性微卫星标记，对两种取食艾菊的蚜虫——艾菊长管蚜（Macrosiphoniella tanacetaria，MA）与暗绿长管蚜（Metopeurum fuscoviride，ME）开展了研究。两种蚜虫均在约60%的已知原栖生境中被发现，但通常二者均以单一种群形式出现（MA占比约50%，ME占比约60%），极少同时在同一植株上共存（共存占比仅约10%），且该共存现象大多仅出现在生长季早期。这种单一种群占优的现象可能源于饲养ME蚜虫的蚂蚁所引发的准表观竞争效应——蚂蚁会主动偏好性地清除或干扰MA蚜虫。从种群遗传学角度来看，两种蚜虫在集合种群（metapopulation）结构下均表现出极强的遗传异质性，且ME的异质性高于MA：二者的FST值分别约为0.4与0.15，种群间基因流水平均较为有限。蚜虫的亚种群大多偏离哈迪-温伯格平衡（Hardy-Weinberg equilibrium），且存在连锁不平衡（linkage disequilibria）现象——这与长期进行孤雌生殖（parthenogenetic reproduction）的动物种群特征相符；多数大样本的FIS值为正，表明种群存在近交现象，且可能存在恋巢行为，这一点在ME种群中尤为显著。分层分析（包括等位基因范围与每基因座等位基因数、分子方差分析（analysis of molecular variance）以及FST分析）结果强烈表明，遗传变异水平主要由宿主植物而非采样位点决定。贝叶斯聚类分析显示，两种蚜虫均具有异质性的历史遗传模式，其亚群数K（即分组数）的取值范围为3至7。基于距离隔离（isolation by distance, IBD）与私有等位基因分析的结果同样证实：MA种群存在有翅秋季雄虫，而ME种群的雄虫无翅且不存在该类雄虫；这种差异会影响种群的遗传结构，使得ME亚种群相比MA亚种群具有更高的近交程度与遗传分化水平。此外，额外的空间排列（ALLELES-IN-SPACE）分析结果显示，两种蚜虫的部分亚种群与其余亚种群存在遗传隔离，这大概率是由地理屏障（如其间分布的建筑与林地）导致的。因此，栖息于半自然生境中的这类艾菊蚜虫，其生物学特性与农业生态系统中被研究的多种害虫蚜虫以及侵染短命作物的蚜虫均存在显著差异：前者飞行意愿极低，因此即便在本研究的小空间尺度下，种群间的分化水平也远高于后者。实际上，通过贝叶斯方法得到的艾菊蚜虫基因型簇数量，与全球范围内的主要害虫——桃蚜（Myzus persicae）的基因型簇数量相当。