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...

A new six-eyed species of the spider genus Alistra Thorell, 1894 from Guangdong, China (Araneae: Hahniidae)

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A new six-eyed species of the spider genus Alistra Thorell, 1894 from Guangdong, China (Araneae: Hahniidae)

Abstract

Guangdong Province, China, possesses an abundant number of karst caves. Cave-dwelling spiders typically exhibit distinct troglomorphic characteristics, such as depigmented bodies and reduced or absent eyes. In this paper, we describe a new species of the genus Alistra Thorell, 1894, Alistra jinlong sp. nov. (male and female), discovered in a karst cave in Guangdong. Notably, this new species possesses six eyes, a feature that distinguishes it from all known congeners. Detailed illustrations of the habitus and copulatory organs, along with a distribution map, are provided.

Ailan He, Yangxin Fan, Shuyi Hou, Jing Guo "A new six-eyed species of the spider genus Alistra Thorell, 1894 from Guangdong, China (Araneae: Hahniidae)," The Pan-Pacific Entomologist, 102(2), 82-87, (30 June 2026) https://doi.org/10.3956/2025-102.2.82