Insects and pollinators
Jumping spiders experience two distinct sleep stages
A study of Australian jumping spiders revealed resting behaviors similar to REM sleep, marking the first experimental proof of true sleep cycles in arachnids.
Reported by Phys.org · · 2 min read
Australian jumping spiders experience genuine, structured sleep that includes a phase resembling rapid eye movement, or REM sleep, according to a recent investigation. Conducted by scientists at the University of Bonn, the research offers the first thorough behavioral verification that spiders enter genuine sleeping states.
The team tracked adults of Portia fimbriata, an arachnid species about the physical size of a one-euro coin. Unlike most spiders that rely on webs, members of this genus actively hunt other spiders and deploy calculated tactics, such as shaking web strands to imitate trapped prey. These complex strategies have long led biologists to suspect that the species possesses sophisticated mental capabilities.
To observe their nocturnal habits, researchers housed individual spiders inside twelve-centimeter plastic dishes under controlled light settings for several continuous cycles. Using infrared video equipment, the team monitored body postures and periods of immobility during the night. The recordings revealed that the animals cycled through two separate rest stages, periodically displaying muscle twitches alongside ocular shifts.
Because monitoring brain signals directly in living spiders remains unfeasible, the authors relied entirely on behavioral indicators. They tested whether the creatures were truly asleep by playing acoustic signals and tracking response speeds. The spiders took longer to react while resting and later engaged in sleep rebound, taking extra rest following periods when their downtime was interrupted.
Designing sound cues that elicited clear reactions proved to be one of the project's primary hurdles, alongside managing vast amounts of visual recordings. The authors noted that extending sleep investigations beyond traditional vertebrate models could clarify how dormant states originated and whether dreamlike phases serve a fundamental biological role across animal life.
Future projects by the team will explore whether similar rest patterns occur across other spider families. Researchers also intend to compare wild populations with laboratory subjects, examine the neurological mechanisms involved, and analyze how environmental challenges, such as nighttime artificial illumination, might disrupt arachnid rest.
