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Hydrogen isotope ratios of sedimentary leaf waxes (δ2HWax values) are increasingly used to reconstruct past hydroclimate. Here, we add δ2HWax values from 19 lakes and four swamps on 15 tropical Pacific islands to an updated global compilation of published data from surface sediments and soils. Globally, there is a strong positive linear correlation between δ2H values of mean annual precipitation (δ2HP values) and the leaf waxes n‐C29‐alkane (R2 = 0.74, n = 665) and n‐C28‐acid (R2 = 0.74, n = 242). Tropical Pacific δ2HWax values fall within the predicted range of values based on the global calibration, and the largest residuals from the global regression line are no greater than those observed elsewhere, despite large uncertainties in δ2HP values at some Pacific sites. However, tropical Pacific δ2HWax values in isolation are not correlated with estimated δ2HP values from isoscapes or from isotope‐enabled general circulation models. Palynological analyses from these same Pacific sediment samples suggest no systematic relationship between any particular type of pollen distribution and deviations from the global calibration line. Rather, the poor correlations observed in the tropical Pacific are likely a function of the small range of δ2HP values relative to the typical residuals around the global calibration line. Our results suggest that δ2HWax values are currently most suitable for use in detecting large changes in precipitation in the tropical Pacific and elsewhere, but that ample room for improving this threshold exits in both improved understanding of δ2H variability in plants, as well as in precipitation., Plain Language Summary: Past precipitation patterns are difficult to reconstruct, limiting our ability to understand Earth’s climate system. Geochemists reconstruct past precipitation by measuring the amount of heavy hydrogen naturally incorporated into the waxy coating of leaves, which is preserved in mud that accumulates in lakes, soils, and oceans. Heavy hydrogen in leaf waxes is strongly correlated with local precipitation, allowing us to learn about rainfall intensity, temperature, and cloud movement. However, no existing calibration studies include sites from the tropical Pacific, home to the most intense rainfall on the planet and populations that rely on rain for drinking water and farming. We measured heavy hydrogen in leaf waxes from tropical Pacific islands and show that although values are within the global calibration error, no precipitation relationship exists within the region. Plant type distributions do not explain the lack of correlation, which is best attributed to poorly constrained estimates of heavy hydrogen in local rain and the relatively small range of variability within the region. At present, heavy hydrogen from ancient leaf waxes can show large changes in past precipitation, but improved process‐level understanding is needed to use this tool to understand smaller changes in the tropical Pacific and elsewhere., Key Points: Leaf wax 2H/1H ratios are correlated with mean annual precipitation 2H/1H ratios globally, but not in the tropical Pacific. Deviations from the global relationship between precipitation leaf wax 2H/1H ratios cannot be predicted from palynological assemblages. Small range and large uncertainties in estimates of tropical Pacific precipitation 2H/1H ratios likely account for poor correlations., Swiss National Science Foundation, National Science Foundation (NSF) http://dx.doi.org/10.13039/100000001, Natural Environment Research Council (NERC) http://dx.doi.org/10.13039/501100000270, Department of Education and Training, Australian Research Council (ARC) http://dx.doi.org/10.13039/501100000923, http://10.0.15.89/ethz-b-000412154

Espiritu Santo is one of the 82 islands of the archipelago of Vanuatu and is the largest, highest, and most biodiverse of the insular country. Climatic changes linked to El Niño and extreme events such as cyclones and volcanic eruptions are a daily challenge in this remote area. These events can be recorded in sedimentary archives. Here we present a multi-proxy investigation of sediment cores retrieved from two small lakes located on the West coast of Espiritu Santo. Although the records span the last millennium, high-resolution radiocarbon dating of macrofossils reveals a rapid accumulation of sediment in the past 100 years. The high accumulation rate coupled with the high-resolution dating of freshwater sediments allows us to compare the 14C bomb curve with the biogeochemical proxies of the sedimentary records. The results can then be validated against written and oral historical records linked with the societal perception of recent environmental changes in this vulnerable ecosystem.

A growing number of researchers suggest that female homosexuality is at least in part influenced by genetic factors. Unlike for male homosexuality, few familial studies have attempted to explore maintenance of this apparently fitness-detrimental trait in the population. Using multiple recruitment methods, we explored fecundity and sexual orientation within the pedigrees of 1,458 adult female respondents. We compared 487 homosexual and 163 bisexual with 808 heterosexual females and 30,203 of their relatives. Our data suggest that the direct fitness of homosexual females is four times lower than the direct fitness of heterosexual females of corresponding ages. The prevalence of nonheterosexuality within the homosexual female respondents' families (2.83%) appear to be more than four times higher than the basal prevalence in the Italian population (0.63%). Pedigree size and relative fecundity in both the paternal and maternal sides of the homosexual women's families were significantly higher than in the heterosexuals' families. If confirmed, the relative average fecundity increase within the family seems to offset the loss in fitness due to the low direct fitness of homosexual females. Therefore, the balanced fecundity in the homosexual females' families may allow the trait to be maintained at a low-frequency equilibrium in the population.

The colonization of Remote Oceania ~3000 years ago is attributed to the Lapita people, a population originating from South East Asia. First human settlements on these islands are associated with major landscape modifications. However, past hydroclimatic variations, which played a role in the colonization of remote islands, challenge a clear anthropogenic attribution of ecosystem changes. The archipelago of Vanuatu, with its extensive archeological remains of the Lapita culture, is considered a crucial location in the colonization of Remote Oceania. Here we present a sediment record retrieved near the Teouma archeological site, the earliest confirmed Lapita cemetery found in the Pacific Islands. We dated 43 macrofossils from a 4 m long peat core spanning the last 5000 years. Fecal sterols associated with human presence become more abundant during the Lapita period as well as the later Erueti phase. Palmitone downcore concentrations were quantified as a signature for taro, a staple crop introduced by early settlers, and applied as a proxy for the establishment of agriculture. Elemental changes were measured with X-ray fluorescence core-scanning to track soil erosion and provenance. The hydrogen isotopic composition of plant waxes, namely long-chain fatty acids, was measured as a proxy for hydroclimatic changes. A transition towards wetter climatic conditions corresponds to the initial human settlement indicated by archeological remains and fecal sterols. Coupling human-related and climatic proxies on a record spanning the last 5000 years allows us to reconstruct the pre-anthropogenic state of the site, and add insights to the timing of human arrival and the consequent landscape modifications., IAL-IPA 2022 Abstract Book - Lagos Memorias del Territorio