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Gut microbes shape many aspects of organismal biology, yet how these key bacteria transmit among hosts in natural populations remains poorly understood. Recent work in mammals has emphasized either transmission through social contacts or indirect transmission through environmental contact, but the relative importance of different routes has not been directly assessed. Here we used a novel radio-frequency identification-based tracking system to collect long-term high-resolution data on social relationships, space use and microhabitat in a wild population of mice (Apodemus sylvaticus), while regularly characterizing their gut microbiota with 16S ribosomal RNA profiling. Through probabilistic modelling of the resulting data, we identify positive and statistically distinct signals of social and environmental transmission, captured by social networks and overlap in home ranges, respectively. Strikingly, microorganisms with distinct biological attributes drove these different transmission signals. While the social network effect on microbiota was driven by anaerobic bacteria, the effect of shared space was most influenced by aerotolerant spore-forming bacteria. These findings support the prediction that social contact is important for the transfer of microorganisms with low oxygen tolerance, while those that can tolerate oxygen or form spores may be able to transmit indirectly through the environment. Overall, these results suggest social and environmental transmission routes can spread biologically distinct members of the mammalian gut microbiota., (© 2024. The Author(s).)

Recent research on the water content of large igneous provinces (LIPs) has revealed that water has a significant impact on the formation of LIPs. However, most studies focus on the water content of mafic-ultramafic rocks, while relatively little attention has been paid to the water content of continental flood basalts (CFB), which form the major part of LIPs and are characterized by huge volumes (> 1 × 10 5 km 3 ) and short eruption times. Here, we determined water contents of clinopyroxene crystals from the Akesu diabase, which is co-genetic with flood basalts of the Tarim LIP in China. Based on these measurements, we obtained a water content of higher than 1.23 ± 0.49 wt.% for the parental magma to the Tarim CFB and a minimum water content of 1230 ± 490 ppm for the mantle source, thus indicating the presence of a hydrous mantle plume. Combined with previous studies, our results suggest that water plays a key role in the formation of the Tarim LIP. Additionally, the whole-rock compositions of the Akesu diabase indicate a contribution of pyroxenite in the mantle source. This is consistent with a model, in which water was brought into the Tarim mantle plume by a subducted oceanic plate that entered the deep mantle., (© 2024. The Author(s).)

Age is a key parameter in population ecology, with a myriad of biological processes changing with age as organisms develop in early life then later senesce. As age is often hard to accurately measure with non-lethal methods, epigenetic methods of age estimation (epigenetic clocks) have become a popular tool in animal ecology and are often developed or calibrated using captive animals of known age. However, studies typically rely on invasive blood or tissue samples, which limit their application in more sensitive or elusive species. Moreover, few studies have directly assessed how methylation patterns and epigenetic age estimates compare across environmental contexts (e.g. captive or laboratory-based vs. wild animals). Here, we built a targeted epigenetic clock from laboratory house mice (strain C57BL/6, Mus musculus) using DNA from non-invasive faecal samples, and then used it to estimate age in a population of wild mice (Mus musculus domesticus) of unknown age. This laboratory mouse-derived epigenetic clock accurately predicted adult wild mice to be older than juveniles and showed that wild mice typically increased in epigenetic age over time, but with wide variation in epigenetic ageing rate among individuals. Our results also suggested that, for a given body mass, wild mice had higher methylation across targeted CpG sites than laboratory mice (and consistently higher epigenetic age estimates as a result), even among the smallest, juvenile mice. This suggests wild and laboratory mice may display different CpG methylation levels from very early in life and indicates caution is needed when developing epigenetic clocks on laboratory animals and applying them in the wild., (© 2024 The Authors. Molecular Ecology published by John Wiley & Sons Ltd.)