The distribution, spatial clustering, and density of trapdoor spiders in two California coastal dune ecosystems

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  The distribution, spatial clustering, and density of trapdoor spiders in two California coastal dune ecosystems Abstract Coastal dune ecosystems support endemic trapdoor spiders, yet population data for these species are limited. We conducted the first coastal dune trapdoor spider population estimation surveys at Moss Landing State Beach (California) and for Aptostichus stephencolberti Bond 2008 at Sunset State Beach using randomly selected 1m 2 quadrats across ~26,000 m 2 per site. Burrow densities were similar between sites (Sunset: 0.287 burrows/m 2 ; Moss: 0.453 burrows/m 2 ), yielding estimated population sizes of ~35,206 and ~30,959 individuals, respectively. However, spatial analyses revealed contrasting patterns of burrow distribution. At Sunset State Beach, burrow presence was strongly associated with vegetation and occurred closer to plants, despite vegetation being randomly distributed. In contrast, no vegetation–burrow association was detected at Moss Landing, alth...

Discovery of novel non-retroviral endogenous viral elements reveals their long-term co-evolution with spiders

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Discovery of novel non-retroviral endogenous viral elements reveals their long-term co-evolution with spiders

Endogenous viral elements (EVEs) are widespread in the genomes of various organisms and have played a crucial role in evolution. Historically, research on EVEs primarily focused on those derived from retroviruses; however, the significance of non-retroviral EVEs (nrEVEs) has gradually gained recognition. In this study, we employed a novel approach that combines protein structure prediction with sequence analysis to identify a large group of previously unrecognized nrEVEs across spider genomes. Additionally, we identified nrEVE-related messenger RNAs, microRNAs, and PIWI-interacting RNAs in spiders, suggesting that these nrEVEs may be functionally active. We also experimentally confirmed the presence of spider nrEVEs and their transcripts in individual spiders. Evolutionary analysis suggests that these spider nrEVEs originated from an ancestral nuclear arthropod large DNA virus (NALDV) belonging to the order Lefavirales, class Naldaviricetes, approximately 270 million years ago. The integration of these nrEVEs occurred prior to the last common ancestor of the Araneae, indicating a long-term co-evolutionary relationship between these nrEVEs and spiders. Our findings reveal a novel group of nrEVEs and provide valuable insights into their evolutionary relationship with arthropods.

Manli Wang, Hengrui Hu, Just Vlak et al. Discovery of novel non-retroviral endogenous viral elements reveals their long-term co-evolution with spiders, 15 October 2024, PREPRINT (Version 1) available at Research Square [https://doi.org/10.21203/rs.3.rs-4996788/v1]