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

Posted by
  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 (...

Food availability influences adult body mass variability and reproductive traits in a spider

Posted by

 


Food availability influences adult body mass variability and reproductive traits in a spider

Abstract

All animals require food to survive, grow, reproduce, and thus optimize fitness in nature. Food availability can profoundly affect demographic parameters such as longevity and fecundity. Here, we compared reproductive parameters in the false widow spider, Steatoda grossa (Araneae, Theridiidae), when the availability and size of prey (the house cricket, Acheta domesticus) were manipulated. Adult mated female spiders that were fed weekly (constant prey treatment) produced more progeny during their lifetime than females fed every 3 weeks (intermittent prey treatment). Furthermore, the monitoring of fecundity schedules showed that over the first 10 egg sacs, the mean number of neonate spiderlings per egg sac was around 40% higher in constantly fed than intermittently fed spiders. Time intervals between egg sac productions were generally higher when prey availability was lower. Some females lost more than 50% of their body mass after the production of the first egg sac, although reproductive investment tended to decrease thereafter. The amount of prey offered to females significantly affected mass gain between reproductive events, but fewer progeny were produced by females per egg sac, as well as cumulatively over the first three egg sacs, when they were only fed small prey. Starved females that had not produced egg sacs in several months exhibited total reproductive recovery when fed. Our results demonstrate the importance of prey attributes on S. grossa reproduction. Furthermore, females invest remarkably large amounts of resources during each reproductive cycle and over the course of a lifetime.

Dong, Y., Gols, R. & Harvey, J.A. Food availability influences adult body mass variability and reproductive traits in a spider. Oecologia 207, 179 (2025). https://doi.org/10.1007/s00442-025-05818-w