Venom composition of the Iberian adder (Vipera seoanei) from northern Portugal reveals limited sex and size variation

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  Venom composition of the Iberian adder (Vipera seoanei) from northern Portugal reveals limited sex and size variation Abstract Snake venom is a complex and dynamic ecological trait, with high potential for intraspecific variation. In this study, the venom composition of the Iberian adder ( Vipera seoanei ) from the Peneda Mountains of northern Portugal was investigated to explore whether venom varies with body size and sex. Venom proteomes from six individuals representing juvenile, subadult, and adult males and females were characterised using LC–MS/MS, while individual variation was assessed from SDS–PAGE profiles of 18 snakes. LC–MS/MS identified 144 proteins, dominated by phospholipases A 2 (PLA 2 ), snake venom serine proteases (svSP), and C-type lectin-related proteins (CTL). Descriptive comparisons revealed contrasting individual profiles, particularly between the juvenile male, characterised by high svSP and svMP abundance, and the juvenile female, characterised by high ...

Declining freshwater habitats in Greenland may shift diets of the ubiquitous wolf spider Pardosa glacialis

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Declining freshwater habitats in Greenland may shift diets of the ubiquitous wolf spider Pardosa glacialis


Abstract

Freshwater habitats in Arctic landscapes provide essential food resources to predaceous terrestrial fauna. However, climate change threatens the continuation of aquatic resources as increased temperatures prompt widespread drying. We investigated how declines in surface waters in the Arctic may have implications for the diets of the wolf spider Pardosa glacialis (Araneae: Lycosidae), an abundant top predator in western Greenland known to consume both aquatic and terrestrial prey. We estimated the abundance of ground-dwelling prey taxa near and far from shallow ponds to compare resource availability for P. glacialis. We also measured the stable isotopes ratios of carbon and nitrogen of potential prey taxa and used linear mixing models to estimate the relative proportions of aquatic and terrestrial prey in the diets of P. glacialis collected near ponds versus drier, upland locations. Overall, near ponds there was a 3.7 times greater abundance of ground-dwelling organisms compared to locations far from ponds. Near ponds, depleted δ13C values of P. glacialis compared to the upland locations were explained by the consumption of aquatic insects, which were relatively depleted in 13C compared to terrestrial ground-dwelling and canopy taxa. Our linear mixing model indicated that the mean relative contribution of aquatic taxa to the diets of P. glacialis at pond locations was ~ 23% versus ~ 0% at upland locations, though these results were accompanied by significant uncertainty. Our results emphasize the importance of Arctic ponds in providing habitat to potential prey of terrestrial predators. We highlight how climate change, and the continued disappearance of aquatic habitats, could disrupt critical linkages between aquatic insects and terrestrial predators.

Bliska, H.M., DeSiervo, M.H., Virginia, R.A. et al. Declining freshwater habitats in Greenland may shift diets of the ubiquitous wolf spider Pardosa glacialis. Polar Biol (2024). https://doi.org/10.1007/s00300-024-03259-4