Behavioral evidence for two-stage sleep in spiders

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  Behavioral evidence for two-stage sleep in spiders Abstract Sleep is a fundamental behavioral state found across the animal kingdom, yet most of what we know about sleep is heavily vertebrate-biased. Studies are scarce or nonexistent in all but a few invertebrate lineages. A recent study of an REM sleep-like behavior in a jumping spider has reported unexpected parallels to sleep expression in vertebrates. So far, experimental evidence that these behavioral indicators truly represent sleep was lacking in spiders. Here, we present a comprehensive investigation into sleep behavior in the spider Portia fimbriata (Salticidae). We demonstrate diurnal activity, a free-running circadian rhythm, robust sleep architecture, regularly occurring REM-like behaviors, elevated arousal thresholds during those REM-like states, as well as rebound effects following sleep disruption. We conclude that the behavior we observe in spiders is behavioral sleep, providing evidence for an REM-like sleep sub...

How to ensure a species remains in oblivion: the history of Nemesia hispanica L. Koch, 1871 (Araneae: Mygalomorphae: Nemesiidae)

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How to ensure a species remains in oblivion: the history of Nemesia hispanica L. Koch, 1871 (Araneae: Mygalomorphae: Nemesiidae)

Abstract

The taxonomic history of Nemesia hispanica L. Koch 1871 is revised; it is a species long affected by misidentifications since 1871. New material from Monte Abantos, San Lorenzo de El Escorial, Madrid (Spain) is analyzed, providing the first descriptions of males, adult females, and burrow structure—particularly relevant given that the holotype seems to be an immature specimen. Morphology of copulatory organs and the distinctive burrow architecture allow clear differentiation from other morphologically related species. Finally, the historical chain of misidentifications is examined, along with its implications for Iberian nemesiid diversity and taxonomy.

Pertegal, C., Narro, A. & Olivares, P. (2026) How to ensure a species remains in oblivion: the history of Nemesia hispanica L. Koch, 1871 (Araneae: Mygalomorphae: Nemesiidae). Zootaxa , 5869 (1), 93–104. https://doi.org/10.11646/zootaxa.5869.1.7