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

Posted by
  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 ...

Is predation by ants driving the evolution of tarantulas? First report of tarantulas (Araneae, Theraphosidae) actively using urticating setae against invertebrates

Posted by

 


Is predation by ants driving the evolution of tarantulas? First report of tarantulas (Araneae, Theraphosidae) actively using urticating setae against invertebrates

Abstract

The use of urticating setae by tarantulas from the Americas and the Caribbean has been known for centuries and is considered a defensive behavior against vertebrate predators. However, their passive use against invertebrates, such as parasitic fly maggots and ants, has also been recently proposed, but no active use of these setae against invertebrates has been observed or tested. In this study, eight tarantula specimens representing four different species from the family Theraphosidae were tested in twelve tests with the army ant Eciton burchelli and the carpenter ant Camponotus rufipes. Four spiders interacted with Eciton burchelli, and one interacted with Camponotus rufipes. The defensive behavior was distinct from that used against vertebrates, as the spider rubs the lower posterolateral region of the abdomen with downward and outward movements of the hind legs and uses silk threads. Scanning electron microscopy (SEM) demonstrated that the ants were entangled with urticating setae, primarily of type I morphology. Type I urticating setae are found exclusively in an important clade of theraphosine spiders, the tribe Theraphosini, which includes the largest known spiders. It is hypothesized here that protection against predation by ants due to the emergence of a specific type of urticating seta may be one of the factors responsible for the success of tarantulas in the New World.

Bertani, R. (2026). Is predation by ants driving the evolution of tarantulas? First report of tarantulas (Araneae, Theraphosidae) actively using urticating setae against invertebrates. Scientific Reports, 16(1), 23769. https://doi.org/10.1038/s41598-026-64167-7