Spider webs that serve as snares are one of the most fascinating and abundant type of animal architectures. In many cases they include an adhesive coating of silk lines-so-called viscid silk-for prey capture. The evolutionary switch from silk secretions forming solid fibres to soft aqueous adhesives remains an open question in the understanding of spider silk evolution. Here we functionally and chemically characterized the secretions of two types of silk glands and their behavioural use in the cellar spider, Pholcus phalangioides. Both being derived from the same ancestral gland type that produces fibres with a solidifying glue coat, the two types produce respectively a quickly solidifying glue applied in thread anchorages and prey wraps, or a permanently tacky glue deployed in snares. We found that the latter is characterized by a high concentration of organic salts and reduced spidroin content, showing up a possible pathway for the evolution of viscid properties by hygroscopic-salt-mediated hydration of solidifying adhesives. Understanding the underlying molecular basis for such radical switches in material properties not only helps to better understand the evolutionary origins and versatility of ecologically impactful spider web architectures, but also informs the bioengineering of spider silk-based products with tailored properties.

• Klíčová slova
• adhesive, convergence, piriform silk, spider silk, spidroin, viscid silk,
• MeSH
• adheziva chemie   MeSH
• biologická evoluce MeSH
• hedvábí * chemie   MeSH
• pavouci * chemie   MeSH
• predátorské chování MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• adheziva MeSH
• hedvábí * MeSH

Spiders are a highly diversified group of arthropods and play an important role in terrestrial ecosystems as ubiquitous predators, which makes them a suitable group to test a variety of eco-evolutionary hypotheses. For this purpose, knowledge of a diverse range of species traits is required. Until now, data on spider traits have been scattered across thousands of publications produced for over two centuries and written in diverse languages. To facilitate access to such data, we developed an online database for archiving and accessing spider traits at a global scale. The database has been designed to accommodate a great variety of traits (e.g. ecological, behavioural and morphological) measured at individual, species or higher taxonomic levels. Records are accompanied by extensive metadata (e.g. location and method). The database is curated by an expert team, regularly updated and open to any user. A future goal of the growing database is to include all published and unpublished data on spider traits provided by experts worldwide and to facilitate broad cross-taxon assays in functional ecology and comparative biology. Database URL:https://spidertraits.sci.muni.cz/.

• MeSH
• členovci * MeSH
• databáze faktografické MeSH
• ekosystém MeSH
• fenotyp MeSH
• pavouci * genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The coexistence of phylogenetically related species is an attractive topic because of the potentially intense interspecific competition. The most often investigated mechanisms mediating coexistence of these species are environmental filtering and niche partitioning. However, the role of other factors, such as species-specific parasites, is still poorly understood. Along the riparian understory of a tropical forest, we explored niche occupation and coexistence between Chrysso intervales and Helvibis longicauda, two related syntopic web-building spiders. We also investigated the effect of H. longicauda mortality induced by a specific fungus parasite, Gibellula pulchra, on the dynamic of C. intervales spatial distribution. Coexistence was mediated mainly by a fine-scale horizontal spatial segregation. H. longicauda built webs almost exclusively close to the river, while C. intervales occupied adjacent areas (10-20 m away from margins). We also found differentiation in other niche dimensions that might allow coexistence, such as in plants occupied, height of web placement, width of leaves used for thread attachment and phenology. H. longicauda mortality caused by fungi was higher during winter than in summer. Consequently, the abundance of C. intervales increased at distances close to the river, indicating competitive release through a density-mediated indirect effect. This demonstrates how non-competitive specific-antagonists can indirectly affect other non-hosts competing community members and influence their spatial distribution in fine-scale ranges. We suggest that environmental filtering restricts H. longicauda to cooler regions; niche partitioning leads populations to occupy different vertical strata and competitive exclusion precludes C. intervales to reach river margins, generating an unusual horizontal zonation pattern.

• Klíčová slova
• Coexistence, Competition, Fungal infection, Niche, Parasitism,
• MeSH
• druhová specificita MeSH
• lesy MeSH
• paraziti * MeSH
• rostliny MeSH
• zaměstnání MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH