Opera Lilloana 58 (2025): Spiders of the Province of Tucumán: Diversity and Biology

This work represents an introduction to the fascinating world of spiders, as well as their biology and behavior. It summarizes the current knowledge of the spiders of Tucumán, and represents a starting point for studies at a greater depth. A total of 52 families of spiders (with 222 species) have been recorded in the province, and other 2 families are probably present (as they are found in neighboring provinces). Photos of almost all of the 175 genera of confirmed occurrence are presented; another 18 genera (several of them illustrated as well) are probably present, but they have not been confirmed yet. The phylogeny and classification of the spiders of Tucumán is discussed, and many data on natural history and behavior of the main groups are provided. Although the majority of groups consist of generalist predators, there are also in Tucumán many forms specializing in the capture of different types of prey, from certain groups of insects, such as moths (e.g. Parawixia, some Araneus, or Ocrepeira), grasshoppers (e.g. Argiope), to ants (e.g. Leprolochus, Galianoella, Eilica, which use different techniques to subdue their prey) or bees (e.g. Misumenops); some forms specialize in the capture of other spiders (e.g. Ariamnes, Mimetidae). The aquatic forms (Trechaleidae, Pisauridae, Ancylometidae) capture aquatic insects, and occasionally small fish or tadpoles. The varied methods of capture and web construction are also discussed, from spiders that hunt or build trapdoors on the ground, to sit-and-wait hunters that stalk pollinators among flowers, weavers of elaborate capture webs (some designed to entangle, some to adhere), or special strategies such as throwing a sticky substance through the chelicerae that serves to immobilize prey (Scytodes, spitting spiders), wrapping prey running in a circular motion around it (Oecobiidae and Hersiliidae), or awaiting a passing prey while buried under the sand (Sicarius). This work is accompanied with more than 60 videos (publicly available on the web), showing many of the behaviors discussed in the text.