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 ...

Hiding in plain sight: Microhabitat selection by the trunk-dwelling spider Ypypuera crucifera (Araneae, Hersiliidae), with notes on its natural history

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Hiding in plain sight: Microhabitat selection by the trunk-dwelling spider Ypypuera crucifera (Araneae, Hersiliidae), with notes on its natural history

Abstract

Habitat selection provides biological advantages, including benefits for foraging, reproduction, and predator avoidance. Abiotic factors like vegetation and substrate characteristics play a critical role in this process. This study examined the microhabitat selection of the two-tailed trunk-dwelling spider Ypypuera crucifera in semideciduous dry tropical forests. Rough, circular tree trunks were preferred, likely aiding escape behaviors and reducing predation risk, while smooth or concave trunks were avoided. Spider abundance peaked at mid-height positions (100–160 cm), aligning with predator avoidance strategies. Contrary to expectations, lichen coverage did not influence occupancy, despite its potential role in camouflage for Y. crucifera. Observations revealed reproductive behaviors, including guarded, trunk-attached egg sacs. These findings enhance understanding of Y. crucifera's habitat preferences and natural history, highlighting the importance of tree trunk characteristics in shaping its ecology.

Vanessa Cardoso Pereira, Leonardo Sousa Carvalho "Hiding in plain sight: Microhabitat selection by the trunk-dwelling spider Ypypuera crucifera (Araneae, Hersiliidae), with notes on its natural history," Invertebrate Biology, 144(2), (12 September 2025) https://doi.org/10.71161/ivb.144.2.2025.00001