A Remarkable Discovery: Exploring a Rare Eresus and Spider Wasp Interaction

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  Photo Credit: © Antonino Rametta . All photographs are used with permission. No part of these images may be reproduced, distributed, or used in any form without the prior written permission of the photographer. A Remarkable Discovery: Exploring a Rare Eresus and Spider Wasp Interaction One of the most rewarding aspects of maintaining Arácnido Taxonomy is hearing from naturalists and photographers around the world who take the time to share their discoveries. Every so often, an email arrives that immediately captures your attention. Not because it claims to rewrite what we know about biodiversity, but because it documents something that very few people have the opportunity to witness. Recently, I was contacted by a naturalist in Sicily who shared a series of exceptionally high-quality photographs of a female ladybird spider ( Eresus ) during what appeared to be an interaction with a spider wasp. Along with the images came a simple question: "Could this be scientifically import...

First report of arm-span competition in buthid scorpions: male-male contest in Tityus cf. rosenbergi Pocock, 1898

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First report of arm-span competition in buthid scorpions: male-male contest in Tityus cf. rosenbergi Pocock, 1898

Abstract

Although courtship and mating behaviors have been described for nearly all scorpion lineages, intrasexual interactions in scorpions remain understudied. Recently, a novel ritualized behavioral unit, termed “arm-span competition,” in which individuals face off and extend their pedipalps laterally, was described from analyses of male-male contests in several scorpionid species. Here, we present the first documented observation of arm-span competition in a buthid scorpion, Tityus cf. rosenbergi Pocock, 1898. Interestingly, both T. cf. rosenbergi and most scorpionid species known to engage in arm-span competition exhibit a similar sexual dimorphism: males have markedly longer and more slender pedipalps than females. We suggest that the elongated pedipalps in males of these species might be the result of selective pressure related to ritualized arm-span competition. We also highlight the potential for citizen science to contribute rare observations to scientific literature.

Aunque se han descrito comportamientos de apareamiento para casi todos los linajes de escorpiones, las interacciones intrasexuales siguen poco estudiadas. Recientemente, a partir del análisis de luchas macho-macho en algunos escorpiónidos, se describió una nueva unidad de comportamiento ritualizado denominada “competencia por extensión de pedipalpos” en que los individuos se enfrentan extendiendo sus pedipalpos lateralmente. En este trabajo, presentamos la primera observación documentada de este comportamiento en un bútido, Tityus cf. rosenbergi Pocock, 1898. Tanto T. cf. rosenbergi como la mayoría de las especies de escorpionidos en que se describió este comportamiento, exhiben un dimorfismo sexual similar: los machos tienen pedipalpos notablemente más elongados y delgados que las hembras. Con esta observación, sugerimos que los pedipalpos de los machos en estas especies sean el resultado de la presión selectiva relacionada con la competencia ritualizada por extensión de pedipalpos. Además, enfatizamos el potencial de la ciencia ciudadana para contribuir con observaciones raras a la literatura científica.

Jules Thornton Wyman, Julien Wright-Ueda, Quinn Agnew, Ismael Castellano, Yuri Simone "First report of arm-span competition in buthid scorpions: male-male contest in Tityus cf. rosenbergi Pocock, 1898," The Journal of Arachnology, 52(3), 210-213, (5 January 2025) https://doi.org/10.1636/JoA-S-23-009