Silk physico-chemical variability and mechanical robustness facilitates intercontinental invasibility of a spider

Abstract

There are substantive problems associated with invasive species, including threats to endemic organisms and biodiversity. Understanding the mechanisms driving invasions is thus critical. Variable extended phenotypes may enable animals to invade into novel environments. We explored here the proposition that silk variability is a facilitator of invasive success for the highly invasive Australian house spider, Badumna longinqua. We compared the physico-chemical and mechanical properties and underlying gene expressions of its major ampullate (MA) silk between a native Sydney population and an invasive counterpart from Montevideo, Uruguay. We found that while differential gene expressions might explain the differences in silk amino acid compositions and protein nanostructures, we did not find any significant differences in silk mechanical properties across the populations. Our results accordingly suggest that B. longinqua’s silk remains functionally robust despite underlying physico-chemical and genetic variability as the spider expands its range across continents. They also imply that a combination of silk physico-chemical plasticity combined with mechanical robustness might contribute more broadly to spider invasibilities.

1000 spider silkomes: Linking sequences to silk physical properties

“…The transcriptomes of 1774 individual spiders were sequenced, which included 1098 species belonging to 441 genera and 76 families, globally sampled from four continents. Redundant sampling was performed for certain species to observe locality or sex differences in spidroin expression ( 22 , 38 ) and sequence variations within species. After the curation of the assembled transcripts, a total of 11,155 putative spidroin genes were identified ( Fig.…”

Can Wolf Spider Mothers Detect Insecticides in the Environment? Does the Silk of the Egg‐Sac Protect Juveniles from Insecticides?

“…Silk is covered by a lipid wax that spiders use as a physical barrier against desiccation and entrance of insecticides (Zhao et al 2006) and as a pheromone source for mothers to identify the status of their egg‐sac contents (Ruhland et al 2019). Although the silk and structure of egg‐sacs can vary greatly (Lewis 2006; Garb et al 2010; Vetter and Carrol 2013; Viera et al 2019), insecticides generally penetrate an egg‐sac and kill the juveniles (Vetter 2015). For example, in the laboratory, cypermethrin at 9% generates an ovicide effect in the spider Latrodectus geometricus (Flores et al 2007), and imidacloprid at 0.05% provokes 78% mortality (Vetter 2015).…”

The Spider Silk Standardization Initiative (S3I): A Powerful Tool to Harness Biological Variability and to Systematize the Characterization of Major Ampullate Silk Fibers Spun by Spiders from Suburban Sydney, Australia

“…We anaesthetized each spider collected using CO 2 and pinned them 2019) (Viera et al, 2019). We weighed the spiders immediately upon collection and prior to silking to ensure that capture and/or housing the spiders did not result in significant (>20% of captured body mass) weight loss.…”