A new species of the mygalomorph spider genus Euagrus Ausserer (Araneae: Euagridae) from central Mexico and new records of E. gus Coyle from Tlaxcala

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  A new species of the mygalomorph spider genus Euagrus Ausserer (Araneae: Euagridae) from central Mexico and new records of E. gus Coyle from Tlaxcala Abstract  A new species of the spider genus Euagrus Ausserer, 1875 from temperate pine-oak forests in the states of Tlaxcala and Hidalgo, Mexico is described: E. pulque sp. nov. The description of the new species is based on male and female adult specimens. Additionally, Euagrus gus Coyle, 1988 is recorded for the very first time in the state of Tlaxcala. These species have sympatric distributions in La Malinche National Park, Tlaxcala. With this description, the diversity of the genus increases to 23 species, with Mexico harboring the highest diversity with 17 described species.  Valdez-Mondragón, A., Salinas-Velasco, H. V. & Bueno-Villegas, J. (2026). A new species of the mygalomorph spider genus Euagrus Ausserer (Araneae: Euagridae) from central Mexico and new records of E. gus Coyle from Tlaxcala. Zootaxa 5810 (...

Behavioral manipulation in a cobweb spider: insights from comparisons between parasitized and healthy spiders

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Behavioral manipulation in a cobweb spider: insights from comparisons between parasitized and healthy spiders

Abstract

Some Darwin wasps of the Polysphincta genus group (Ichneumonidae, Pimplinae) are ectoparasitoids that induce behavioral alterations in their host spiders, resulting in the construction of modified webs, structures known as "cocoon webs”. One relevant aspect for comprehending the manipulation mechanism employed by these wasps involves comparing the structures of webs built by individuals during manipulation with webs constructed during other periods of the spiders' lives. In this study, we present a novel instance of behavioral modification in Cryptachaea jequirituba (Araneae: Theridiidae) parasitized by Zatypota alborhombarta and assess whether cocoon webs are associated with webs constructed during molting, growing, and maternal care. We observed that cocoon webs constructed by spiders parasitized by last-stage larvae showed a reduction in vertical and gumfoot lines. Additionally, there was an increase in forked distal ends of lines and the presence of silk threads around the web shelter. These web traits likely contribute to enhancing web resistance and stability. In addition, we observed that cocoon webs are similar to webs constructed by spiders during molting and show some similarities with webs built during maternal care. These results suggest that the manipulation mechanisms induced by wasps in this cobweb spider may be based on the activation of innate processes.

Cifuentes-Vargas, E.T., de Pádua, D.G., Santos, A.J. et al. Behavioral manipulation in a cobweb spider: insights from comparisons between parasitized and healthy spiders. J Ethol (2025). https://doi.org/10.1007/s10164-025-00848-6