Beyond Venom and Constriction: Bite Performance and Trophic Ecology in the Genus Drymarchon

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  Beyond Venom and Constriction: Bite Performance and Trophic Ecology in the Genus Drymarchon Abstract Snakes exhibit extreme cranial kinesis that facilitates ingestion of prey with large cross-sectional area, but this ability is widely predicted to reduce bite performance due to decreased structural rigidity. Consequently, most large-bodied snakes rely on envenomation or constriction to subdue prey prior to ingestion. Species within the genus Drymarchon represent a notable exception: these large, non-venomous, non-constricting snakes routinely consume a wide range of prey, including large and potentially dangerous vertebrates, using only simple seizing and pinioning behaviors. Here, we quantify bite performance in three species of Drymarchon ( D. corais, D. couperi, and D. melanurus ), examine morphological predictors of biting performance, compare biting pressure to constriction pressure in similarly sized snakes, and synthesize dietary records across the genus. Our results sh...

Integrative taxonomy for widow spiders (Araneae: Theridiidae) surveillance in Mexico City, Mexico

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Integrative taxonomy for widow spiders (Araneae: Theridiidae) surveillance in Mexico City, Mexico

Abstract

The spiders of the genus Latrodectus (Theridiidae), commonly known as widow spiders, includes species of medical importance due to the high toxicity of their venom. Envenomation can range from mild to severe, occasionally resulting in fatal outcomes. In Mexico, four Latrodectus species have been recorded: L. mactans Fabricius, L. geometricus C. L. Koch, L. hesperus Chamberlin and Ivie, and L. occidentalis Valdez and Espinosa. Until recently, only L. mactans had been reported in Mexico City, though its range appears limited to the Tamaulipecan province and Sierra Madre Oriental. This study reports, for the first time, the presence of L. hesperus and a novel lineage designated as Latrodectus sp. 2 in Mexico City. Spider specimens were collected from 14 localities across Mexico City and identified using both morphological keys and molecular methods. Mitochondrial cytochrome c oxidase subunit I (CO1) was amplified via conventional PCR (Polymerase Chain Reaction) and sequenced to confirm species identity. Of the 24 spiders analyzed, 10 were identified as L. hesperus and 14 as Latrodectus sp. 2. Phylogenetic analyses validated the presence of both taxa.

Salceda-Sánchez, B. ., Sánchez-Montes, S. ., Ibarra-Anaya, A. L. ., Zazueta-Islas, H. M. ., Landa-Flores, M. G. ., Orantes-Ramírez, V. J. ., Mejía-Guevara, M. D. . ., Alarid-Villa, B. G. ., & Huerta, H. . (2025). Integrative taxonomy for widow spiders (Araneae: Theridiidae) surveillance in Mexico City, Mexico. Revista Chilena De Entomología, 51(4). Retrieved from https://www.biotaxa.org/rce/article/view/88152