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