The chromosome-level genome of Mesobuthus martensii provides insights into its evolution and the diversity of venom peptides

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  The chromosome-level genome of Mesobuthus martensii provides insights into its evolution and the diversity of venom peptides Abstract Mesobuthus martensii , the source species of the traditional Chinese medicine “Quanxie”, has long been utilized for its therapeutic properties. Venom peptides are recognized as the major active molecular basis of these pharmacological activities. Despite this, their development as therapeutic agents remains poorly explored. In this study, we performed an integrated multi-omics investigation to systematically explore the venom peptides of Mesobuthus martensii . We generated a chromosome-level genome assembly of Mesobuthus martensii using third-generation sequencing technologies, yielding a genome size of 1.08 Gb with a contig N50 of 46.46 Mb. Integrated genomic and transcriptomic analyses led to the identification of 51 putative novel venom peptide candidates. From the broader venom peptide set, five lysine- and arginine-rich candidates were select...

Maternal care thwarts parasitoids in the invasive brown widow spider (Latrodectus geometricus)

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Maternal care thwarts parasitoids in the invasive brown widow spider (Latrodectus geometricus)

Abstract

Maternal care can maximize offspring survival and may contribute to the establishment success of invasive species. The brown widow spider, Latrodectus geometricus, is a successful invader worldwide. Here, we investigated the role of maternal care in enhancing its success. We compared the defence mechanisms of the invasive L. geometricus with those of another widow spider native to the Negev desert, Latrodectus pallidus, against an egg sac parasitoid wasp. Both spider species exhibited guarding behaviours following exposure to wasps; however, only L. geometricus efficiently evaded and successfully killed the parasitoid. Accordingly, its egg sacs were parasitized less frequently than those of L. pallidus. Next, we evaluated the defensive role of the silk spike-like structures on L. geometricus egg sacs. When spikes were removed from half of the egg sac surface, the wasps laid more eggs on the spike-free side. In an additional experiment, L. geometricus females increased spike density on subsequent egg sacs after exposure to the parasitoid. We showed that L. geometricus employs both behavioural defences and modifications to the egg sac structure to protect against the parasitoid. These defences may provide L. geometricus with an advantage over native species in its invasive range, potentially contributing to its invasion success.

Arabesky Valeria, Johnson Alfred Daniel, Rozenberg Tamir, Lubin Yael, Segoli Michal and Mowery Monica A. 2025 Maternal care thwarts parasitoids in the invasive brown widow spider (Latrodectus geometricus)Proc. R. Soc. B.29220242735 http://doi.org/10.1098/rspb.2024.2735