Nariman Nijat, Entling Martin H, Krehenwinkel Henrik, Kennedy Susan
Institute of Organismic and Molecular Evolution (iomE), Johannes Gutenberg-University of Mainz, Hanns-Dieter-Hüsch-Weg 15, Mainz, 55128, Germany.
iES Landau, Institute for Environmental Sciences, Ecosystem Analysis, University of Kaiserslautern-Landau (RPTU), Landau, 76829, Germany.
Microb Ecol. 2025 Jul 2;88(1):70. doi: 10.1007/s00248-025-02565-6.
Mermessus trilobatus, an invasive North American linyphiid spider, has expanded its invasion range up to 1400 km in Europe, accelerating its dispersal speed in less than 40 years. The high heritability of dispersal behaviour and the spatial sorting of high and low dispersers indicate a genetic basis of dispersal behaviour. However, microbial endosymbionts can moderate dispersal behaviour in related species (Rickettsia in Erigone atra). Hence, dispersal behaviour in M. trilobatus might also be dictated by the activity of dispersal-mediating endosymbionts. Here, we investigated the microbiome of invasive M. trilobatus spiders extracted from (1) high- and low-dispersive individuals and (2) spiders originating from locations close to the edge and core of the expansion. We examine the microbiomes for the presence of potential dispersal- and reproduction-mediating bacterial strains and compare the microbial assemblages of spiders based on their dispersal behaviour and locations of origin. The composition of microbial assemblages was similar among spiders of different geographic origins and dispersal behaviour. However, microbial richness was lower in high- than in low-dispersive individuals. Surprisingly, none of the known dispersal- or reproduction-altering endosymbionts of arthropods was identified in any tested spider. This contrasts with published results from North America, where M. trilobatus is a known host of Rickettsia and Wolbachia. Thus, the invasive European population appears to have lost its associated endosymbionts. As endosymbionts can reduce spider mobility, it is possible that their absence facilitates the spread of the invasive spider population. The absence of endosymbionts among the analysed individuals substantiates the role of genetic mechanisms behind the variable dispersal behaviour of invasive M. trilobatus in Europe.
三裂梅氏蛛（Mermessus trilobatus）是一种入侵性的北美皿蛛科蜘蛛，其在欧洲的入侵范围已扩大至1400公里，在不到40年的时间里加速了扩散速度。扩散行为的高遗传性以及高扩散者和低扩散者的空间分类表明扩散行为存在遗传基础。然而，微生物内共生体可以调节相关物种（如艾氏姬蛛（Erigone atra）中的立克次氏体）的扩散行为。因此，三裂梅氏蛛的扩散行为也可能由介导扩散的内共生体的活动所决定。在此，我们研究了从（1）高扩散和低扩散个体以及（2）来自扩张边缘和核心附近地点的蜘蛛中提取的入侵性三裂梅氏蛛的微生物组。我们检查微生物组中是否存在潜在的介导扩散和繁殖的细菌菌株，并根据蜘蛛的扩散行为和起源地点比较其微生物群落。不同地理起源和扩散行为的蜘蛛之间微生物群落的组成相似。然而，高扩散个体的微生物丰富度低于低扩散个体。令人惊讶的是，在任何测试的蜘蛛中都未鉴定出任何已知的改变节肢动物扩散或繁殖的内共生体。这与北美已发表的结果形成对比，在北美，三裂梅氏蛛是立克次氏体和沃尔巴克氏体的已知宿主。因此，入侵欧洲的种群似乎已经失去了其相关的内共生体。由于内共生体可以降低蜘蛛的移动性，它们的缺失可能促进了入侵蜘蛛种群的扩散。分析个体中内共生体的缺失证实了欧洲入侵性三裂梅氏蛛可变扩散行为背后遗传机制的作用。
