Miriam Ibáñez-Herranz

Anatomically modern humans first settled in Europe at least 45,000 years ago, yet limited genomic data from 45 to 20 thousand years (ka) constrain reconstructions of Upper Palaeolithic population dynamics. Before the Last Glacial Maximum (LGM; ∼26.5 to 19 ka), Gravettian groups (∼34 to 25 ka) were widespread across Europe and genetically diverse, including the Fournol and Věstonice lineages. Here, we present genome-wide data from three Gravettian individuals: two from the Franco-Cantabrian region (Chufín, Spain, and Isturitz, France) and one from Italy (Ostuni1b). Our analyses reveal previously undetected gene flow between eastern and western early Gravettian populations in southwestern Europe, challenging models of regional genetic continuity from the Aurignacian to the Solutrean (∼24 to 19 ka). To investigate population history during the LGM, a period for which human skeletal remains are extremely rare, we analyzed sedimentary ancient DNA from Solutrean Layer 122 at El Mirón Cave (Cantabria, Spain; ∼22,000 calibrated years before the present), recovering ∼14,000 human single-nucleotide polymorphisms. These data support persistence of Fournol-related ancestry in southwestern Europe throughout the LGM.

Hydrogen stable isotopes (δ ² H) preserved in bone collagen have been proposed as a promising proxy for palaeoclimatic reconstruction, though empirical applications remain limited. To evaluate the reliability and scope of this approach, we performed a multiisotopic analysis (δ ¹³ C, δ ¹⁵ N, δ ³⁴ S, and δ ² H) on 50 herbivore bone samples collected from three archaeostratigraphic layers spanning the Aurignacian sequence of Isturitz Cave (France). This archaeological well-preserved, dated and studied site provides a robust framework for testing isotopic proxies across temporal and taxonomic gradients. Our results reveal a progressive δ ² H depletion over ∼3000-year interval, consistent with predicted increasing aridity. We also identified species-specific δ ² H differences, underscoring the need for taxonomic resolution in future applications and in general palaeoclimatic interpretations. While these samples reflect faunal remains accumulated through human activity—introducing potential ecological and sampling biases—they nonetheless provide valuable records of past local conditions. Overall, our findings support the potential of bone collagen δ ² H as a sensitive indicator of past hydrological conditions and a complementary tool for reconstructing both climatic trends and humanenvironment dynamics.

Unpredictable environmental conditions due to climate change affect the availability and quality of food resources, a limiting factor for survival. Behavioral plasticity is one of the most important mechanisms that help individuals to face rapid environmental changes. However, we still lack experimental information on how foraging decisions are modulated by other behavioral traits when facing changes in food resources. In this study we aimed to explore how individual foraging decisions regarding food quality are related to exploratory behavior, cognitive flexibility, and local dominance in wild great tits (Parus major). We offered different food types varying in quality at supplementary feeders and subsequently changed the availability and location of these food types. We then assessed whether the proportion of high-quality food individuals consumed was influenced by their exploratory tendency, reversal learning performance, and local dominance. We found that local dominance (ie distance from territory to the feeder), but not exploratory tendency or reversal learning performance affected the fraction of high-quality food in an individual's diet. Locally dominant individuals were constrained in their response to changes in the quality of available resources, leading them to stay at their preferred feeder even when this was providing low-quality food alone. In conclusion, we show the importance of the social context when studying the behavioral mechanisms of adaptation to changing environments in wild animals.