Nadja Geiger

Nadja Geiger

@nadjageiger.bsky.social

PhD Student @sleeblab.bsky.social | University of Bonn | Behavioural Ecology | Conservation | Photo- & Videography | SciCom | gazing at sleepy inverts 🕷️✨🌿 she/her

292 followers185 following22 posts

Nadja Geiger reposted

Gwen Pearson
@bug-gwen.bsky.social

In addition to being very cute, "Comparing sleep across such different animals can help us understand how sleep evolved, which features are ancient, and what functions different sleep stages may serve." 💤🕷️ 🧪

Perry Beasley-Hall, PhD@pbeasleyhall.bsky.social

A new study has found a species of #jumpingspider experiences at least two sleep stages, including one resembling REM. 🥹🕷️ #entomology #arachnology www.abc.net.au/news/science...

abc.net.auJumping spiders caught on camera sleeping and leg twitching like humansThe most comprehensive study of its kind confirms that jumping spiders go through two phases of sleep, including a REM-like state that is associated with human dreaming.

Nadja Geiger reposted

La Chelle Dame Sans Merci
@chelleraiser.bsky.social

I feel like @aptshadow.bsky.social might appreciate this one: scientists have discovered that Portia jumping spiders experience REM-like sleep, and even make up for it when they're deprived. THE SPIDERS ACCRUE SLEEP DEBT. 🕷️ www.sciencealert.com/spiders-can-...

sciencealert.comSpiders Can Rack Up REM-Like Sleep Debt (And May Even Dream), Just Like HumansTucked in a corner of an enclosure, swaddled in darkness, a tiny spider sleeps.
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Nadja Geiger
@nadjageiger.bsky.social

To summarise: spiders sleep! Their sleep is structured and regulated, and Portia cycles though at least two distinct states: a quiet sleep stage and a recurring, active REM-like stage. 🧵7/9

Nadja Geiger
@nadjageiger.bsky.social

Why does this matter? Spiders differ greatly from vertebrates in their nervous systems, sensory worlds, and ecologies. Similar sleep organisation across such distant animals gives us a new comparative window into when and why sleep evolved. And we are only beginning to look… 🧵8/9

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Nadja Geiger
@nadjageiger.bsky.social

Then we tested arousal thresholds: We measured how quickly spiders responded to an acoustic stimulus while awake, quiescent, and during REM-like phases. Responses were delayed during quiescence, but particularly strongly during the REM-like phases! 🧵5/9

Nadja Geiger
@nadjageiger.bsky.social

And finally, we disrupted their sleep. Following disrupted sleep (blame #Drosophila), the spiders showed rebound effects, a classic sign of sleep homeostasis. 🧵6/9

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Nadja Geiger
@nadjageiger.bsky.social

First, we looked at circadian control: Even without external light cues, the spiders kept their own activity rhythm. This free-running rhythm shows that their sleep-wake cycle is controlled by an internal circadian clock. 🧵3/9

Nadja Geiger
@nadjageiger.bsky.social

Next: sleep architecture! When it’s time to sleep, Portia settles upside-down on a silken hammock, cleans all her legs, then adopts a characteristic resting posture and becomes quiescent. These long quiet phases are repeatedly interrupted by REM-like bouts, just as we saw in Evarcha. 🧵4/9

Nadja Geiger
@nadjageiger.bsky.social

Earlier work revealed REM-like activity in another jumping spider species, including twitching, leg curling, and even retinal movements. But one question remained: were the spiders truly asleep? 🧵2/9

Nadja Geiger reposted

Lauren Sumner-Rooney
@laurensr.bsky.social

Beyond proud of @atal-pande.bsky.social, whose first PhD chapter is out now in @currentbiology.bsky.social! Atal shows that spiders that use their vision to hunt have convergently evolved similar eye arrangements, which imply lots of resampling of frontal space www.sciencedirect.com/science/arti...

sciencedirect.comHunting ecology predicts eye arrangements in the modular visual system of spidersVision is one of the most important senses used by animals and contributes to fundamental behaviors, including foraging, navigation, and mate detectio…

Nadja Geiger reposted

Springer
@springer.springernature.com

🌍 An #OpenAccess study in 'Behavioral Ecology and Sociobiology' investigates abdomen bobbing in the diurnal jumping spider Heliophanus cf. cupreus, revealing its role as a visual signal during predator and conspecific encounters. bit.ly/4uTZd5f @nadjageiger.bsky.social #BehSci 🪲

bit.lyContext-dependent abdomen bobbing in a jumping spider: a dynamic visual signal - Behavioral Ecology and SociobiologySignals function in intra- and inter-specific communication across several different contexts, such as predation, foraging, competition and mate choice. Static signals including shape or color are well-studied, whereas locomotion-related signals remain less understood despite being particularly intriguing as they can be controlled by the animal’s perception of danger or competition. In this study, we explore the potential function of a highly conspicuous dynamic behavior—abdomen bobbing—exhibited by the diurnal jumping spider Heliophanus cf. cupreus during locomotion. Due to the high conspicuousness, we hypothesized that abdomen bobbing could function as a visual signal, specifically as an anti-predatory signal. To test this hypothesis, we first analyzed the behavior and found that bobs occurred almost exclusively during gait stops (98.5%) with 83.5% of gait stops entailing abdomen bobbing. We then examined its context-dependency, measuring the prevalence of abdomen bobbing under five conditions: (1) control, (2) in darkness, (3) during prey encounters, (4) during simulated conspecific encounters (i.e. mirror), and (5) during predator encounters. Abdomen bobbing was virtually absent in darkness and during prey encounters, but significantly increased during conspecific and predator encounters, suggesting active control. The increase in abdomen bobbing when confronted with a predator supports an anti-predatory signaling function, potentially a form of locomotion mimicry. We equally found support for an intra-specific signaling function, which might indicate the co-option of this signal from one context (predatory) to another (conspecific). Our study opens new avenues for investigating the role of motion in spiders for both inter- and intraspecific signaling.
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Nadja Geiger
@nadjageiger.bsky.social

… when spiders faced a mirror image or a predator model, the bobbing increased! 🕷️✨ And this suggests the movement is not random, but flexible and context-dependent. [5/8]

Nadja Geiger
@nadjageiger.bsky.social

And that’s really cool: The spider may use abdomen bobbing as a flexible visual signal for different functions; e.g. to communicate with conspecifics, as well as deter predators! The next big question is:
 what does the receiver actually do when it sees the bob? To be continued. 👀 [6/8]

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Nadja Geiger
@nadjageiger.bsky.social

So then, we tested the spiders in different conditions: ☀️ daylight 🌑 darkness 🪰 prey encounter 🪞 mirror / “conspecific” 🕷️ predator model Basically: does the spider change the bum-wiggle depending on who might see it?…[3/8]

Nadja Geiger
@nadjageiger.bsky.social

Using a simple behavioural setup (basically, we let the spiders walk on a tiny catwalk) we asked: when does the bobbing appear? Our first clue: The spiders mostly bobbed during short pauses, not while walking. Two other jumping spider species paused too, but didn’t bob. 👀 [2/8]

Nadja Geiger reposted

Science Magazine
@science.org

Researchers have identified superparamagnetic macrophages in the livers of rock pigeons to be crucial for magnetic sensing. The finding uncovers an unexpected role for immune cells in sensory perception and may fundamentally change our understanding of animal navigation. https://scim.ag/4nTQ3nq

Nadja Geiger reposted

SLEEB Lab Bonn
@sleeblab.bsky.social

Things that can happen while filming Portia in the field: we had a (not so) little visitor wandering by with his chicks! Not sure who was more surprised… #cassowary #portia #daintree #storiesfromthefield

Nadja Geiger reposted

Daniela Rößler
@roesslerdaniela.bsky.social

🚨 Uh-oh!!! A suuuper hot #PhD opportunity just dropped! My friend and collaborator Massimo De Agrò is looking for someone to explore jumping spider vision and neurophysiology! #psychophysics #jumpingspiders #greatPI - apply!!!! (Deadline December 17th) 🚨

Nadja Geiger reposted

ISBE2026
@isbe2026.bsky.social

Meet our Plenary Speaker Daniela Rößler Fueled by curiosity and a deep love of natural history Daniela discovered a REM-like sleep state in spiders and uses integrative field, lab and comparative approaches to investigate the function, ecology, and evolution of sleep across the spider tree of life.

Nadja Geiger reposted

SLEEB Lab Bonn
@sleeblab.bsky.social

It’s experiment time! While doing things in the field always adds an extra layer of difficulty (and also frustration), it is very rewarding once it works! #mosquitos #rain #stillhappy

Nadja Geiger
@nadjageiger.bsky.social

Back in the field and beyond excited! 🕷️🌞🌿! #Portiafimbriata

SLEEB Lab Bonn@sleeblab.bsky.social

@nadjageiger.bsky.social & @roesslerdaniela.bsky.social are back in the field in Australia filming and experimenting with the best spider in the world - PORTIA. More soon!

Nadja Geiger reposted

ISBE2026
@isbe2026.bsky.social

The Local Organizing Commitee welcomes behavioral ecologists from across the world and of all career stages to enjoy a five-day meeting rich in top-notch science and ample networking opportunities in Turin (Italy), 20-24 July 2026.