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 ...

Are female Pardosa spiders (Araneae: Lycosidae) from a Mexican coffee crop more efficient than males in capturing a standard prey of various sizes?

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Are female Pardosa spiders (Araneae: Lycosidae) from a Mexican coffee crop more efficient than males in capturing a standard prey of various sizes?

Abstract

Wolf spiders (Lycosidae) are considered one of the main groups of predators in economically relevant crops. Despite their importance, most studies have focused on Nearctic species and have aimed to determining diet composition and analyzing predation primarily using female spiders as models. Although it is known that male spiders also hunt and consume prey effectively, the type and quantity of prey consumed by males may, due to sexual dimorphism, complement that of females. There is an evident lack of information regarding to males which limits their knowledge as potential biological control agents. The study aimed to experimentally assess prey acceptance, immobilization time, and the length of predatory behavior in both female and male Pardosa spiders when exposed to a standard prey (Acheta domesticus) of different sizes. Our findings revealed no significant differences between females and males in terms of prey acceptance, immobilization time, or length of predatory behavior. The increase in relative prey size was related to a decrease in prey acceptance by the spiders. Furthermore, prey immobilization time and length of predatory behavioral sequences increased in relation to increasing prey size. Our findings support the idea that both female and male Pardosa spiders are voracious predators with similar trophic attributes. Size emerges as a critical factor in prey selection by these generalist predators. Understanding the preferred prey size range can be useful for selecting beneficial controllers in various crops.

Mauricio Alejandro Olvera Pale, Mauricio Alejandro Olvera Pale, Luis Fernando García Hernández et al. Are female Pardosa spiders (Araneae: Lycosidae) from a Mexican coffee crop more efficient than males in capturing a standard prey of various sizes?, 22 August 2024, PREPRINT (Version 1) available at Research Square [https://doi.org/10.21203/rs.3.rs-4682875/v1]