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Abstract The diversification of a host lineage can be influenced by both the external environment and its assemblage of microbes. Here, we use a young lineage of spiders, distributed along a chronologically arranged series of volcanic mountains, to investigate how their associated microbial communities have changed as the spiders colonized new locations. Using the stick spiderAriamnes waikula(Araneae, Theridiidae) on the island of Hawaiʻi, and outgroup taxa on older islands, we tested whether each component of the “holobiont” (spider hosts, intracellular endosymbionts and gut microbial communities) showed correlated signatures of diversity due to sequential colonization from older to younger volcanoes. To investigate this, we generated ddRAD data for the host spiders and 16S rRNA gene amplicon data from their microbiota. We expected sequential colonizations to result in a (phylo)genetic structuring of the host spiders and in a diversity gradient in microbial communities. The results showed that the hostA.waikulais indeed structured by geographical isolation, suggesting sequential colonization from older to younger volcanoes. Similarly, the endosymbiont communities were markedly different betweenAriamnesspecies on different islands, but more homogeneous amongA.waikulapopulations on the island of Hawaiʻi. Conversely, the gut microbiota, which we suspect is generally environmentally derived, was largely conserved across all populations and species. Our results show that different components of the holobiont respond in distinct ways to the dynamic environment of the volcanic archipelago. This highlights the necessity of understanding the interplay between different components of the holobiont, to properly characterize its evolution.
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Endosymbiont diversity across native and invasive brown widow spider populations
Abstract The invasive brown widow spider,Latrodectus geometricus(Araneae: Theridiidae), has spread in multiple locations around the world and, along with it, brought associated organisms such as endosymbionts. We investigated endosymbiont diversity and prevalence across putative native and invasive populations of this spider, predicting lower endosymbiont diversity across the invasive range compared to the native range. First, we characterized the microbial community in the putative native (South Africa) and invasive (Israel and the United States) ranges via high throughput 16S sequencing of 103 adult females. All specimens were dominated by reads from only 1–3 amplicon sequence variants (ASV), and most individuals were infected with an apparently uniform strain ofRhabdochlamydia. We also foundRhabdochlamydiain spider eggs, indicating that it is a maternally-inherited endosymbiont. Relatively few other ASV were detected, but included two variantRhabdochlamydiastrains and severalWolbachia,Spiroplasmaand Enterobacteriaceae strains. We then diagnostically screened 118 adult female spiders from native and invasive populations specifically forRhabdochlamydiaandWolbachia.We foundRhabdochlamydiain 86% of individuals and represented in all populations, which suggests that it is a consistent and potentially important associate ofL. geometricus. Wolbachiawas found at lower overall prevalence (14%) and was represented in all countries, but not all populations. In addition, we found evidence for geographic variation in endosymbiont prevalence: spiders from Israel were more likely to carryRhabdochlamydiathan those from the US and South Africa, andWolbachiawas geographically clustered in both Israel and South Africa. Characterizing endosymbiont prevalence and diversity is a first step in understanding their function inside the host and may shed light on the process of spread and population variability in cosmopolitan invasive species.
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- Award ID(s):
- 1953223
- PAR ID:
- 10500270
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- Scientific Reports
- Volume:
- 14
- Issue:
- 1
- ISSN:
- 2045-2322
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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