Behavioral evidence for two-stage sleep in spiders

Posted by
  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...

Elevated Temperatures Disrupt Wolbachia-Induced Feminisation and Reshape Microbial Community Dynamics Across Generations in a Spider Host

Posted by

 


Elevated Temperatures Disrupt Wolbachia-Induced Feminisation and Reshape Microbial Community Dynamics Across Generations in a Spider Host

ABSTRACT

Longitudinal microbial interactions within a host are challenging to study, leading to a focus on constructed microbial communities in vitro settings. Here, we take advantage of a naturally defined microbial community within a spider host to study how elevated temperatures influence microbial dynamics and phenotypes across host generations. The spider Mermessus fradeorum hosts up to five endosymbionts, including a Wolbachia strain, W1, which induces feminisation, causing genetic males to develop as phenotypic females, skewing sex ratios and promoting symbiont spread. Despite this, Wolbachia 1 persists at intermediate frequencies in wild populations. We hypothesised that elevated temperatures might reduce penetration of the feminisation phenotype, potentially by altering symbiont dynamics and maternal transmission. We exposed spiderlings co-infected with Wolbachia 1 to elevated temperatures for one generation and measured feminisation rate, symbiont transmission, and titre across three generations. Feminisation was unaffected in the exposed (F1) generation but declined in subsequent generations (F2, F3) that were not directly exposed. This multigenerational effect was linked to shifts in symbiont community dynamics: low feminisation coincided with high abundance of one symbiont, Rickettsiella, a decline in Wolbachia 1 transmission, and complete loss of another symbiont, Tisiphia. Our findings demonstrate how environmental history shapes the evolutionary stability of microbial communities and their induced phenotype in their natural host.

Mackevicius-Dubickaja, V., White, J. A., Williams, E. E., Klement, E., Gottlieb, Y., & Doremus, M. R. (2026). Elevated Temperatures Disrupt Wolbachia-Induced Feminisation and Reshape Microbial Community Dynamics Across Generations in a Spider Host. Molecular Ecology, 35(9), e70371. https://doi.org/10.1111/mec.70371