Behavioral evidence for two-stage sleep in spiders

  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 species of Mesiotelus Simon (Araneae: Liocranidae) from Turkey

 


A new species of Mesiotelus Simon (Araneae: Liocranidae) from Turkey

ABSTRACT

A new species of the liocranid spider genus Mesiotelus, M. aladaghensis sp. n. (male and female), is described in Aladağlar National Park, Niğde Province, Turkey. Its general habitus and genitalia are illustrated. The description and collection data for this species are also provided.

Düzelten Balli, Z., & Türkeş, T. (2026). A new species of Mesiotelus Simon (Araneae: Liocranidae) from Turkey. Journal of Natural History, 60(37–40), 2009–2017. https://doi.org/10.1080/00222933.2026.2716814