Regularly occurring bouts of retinal movements suggest an REM sleep–like state in jumping spiders

• DOI: 10.1073/pnas.2204754119
• Publication Date: 2022-08-08T19:16:07Z
• Authors: Daniela C. Rößler; Kris Kim; Massimo De Agrò; Alex Jordan; C Giovanni Galizia; Paul S. Shamble
• Keywords: Jumping spider; Sleep

Sleep and sleep-like states are present across the animal kingdom, with recent studies convincingly demonstrating in arthropods, nematodes, even cnidarians. However, existence of different sleep phases taxa is as yet unclear. In particular, study rapid eye movement (REM) still largely centered on terrestrial vertebrates, particularly mammals birds. The most salient indicator REM eyes during this phase. Movable eyes, however, have evolved only a limited number lineages-an adaptation notably absent insects arthropods-restricting cross-species comparisons. Jumping spiders, possess movable retinal tubes to redirect gaze, newly emerged spiderlings, these movements can be directly observed through their temporarily translucent exoskeleton. Here, we report evidence for an state invertebrate: periodic bouts coupled limb twitching stereotyped leg curling behaviors nocturnal resting jumping spider. Observed were consistent, including regular durations intervals, both increasing over course night. That characteristic exist highly visual, long-diverged lineage further challenges our understanding state. Comparisons such lineages likely hold important questions answers about visual brain well origin, evolution, function sleep.