Longitudinal evidence that older parents produce offspring with longer telomeres in a wild social bird.

As telomere length (TL) often predicts survival and lifespan, there is considerable interest in the origins of inter-individual variation in TL. Cross-generational effects of parental age on offspring TL are thought to be a key source of variation, but the rarity of longitudinal studies that examine the telomeres of successive offspring born throughout the lives of parents leaves such effects poorly understood. Here, we exploit TL measures of successive offspring produced throughout the long breeding tenures of parents in wild white-browed sparrow weaver (Plocepasser mahali) societies, to isolate the effects of within-parent changes in age on offspring TLs. Our analyses reveal the first evidence to date of a positive within-parent effect of advancing age on offspring TL: as individual parents age, they produce offspring with longer telomeres (a modest effect that persists into offspring adulthood). We consider the potential for pre- and post-natal mechanisms to explain our findings. As telomere attrition predicts offspring survival to adulthood in this species, this positive parental age effect could impact parent and offspring fitness if it arose via differential telomere attrition during offspring development. Our findings support the view that cross-generational effects of parental age can be a source of inter-individual variation in TL.

Using ancient sedimentary DNA to forecast ecosystem trajectories under climate change.

Ecosystem response to climate change is complex. In order to forecast ecosystem dynamics, we need high-quality data on changes in past species abundance that can inform process-based models. Sedimentary ancient DNA (sedaDNA) has revolutionised our ability to document past ecosystems' dynamics. It provides time series of increased taxonomic resolution compared to microfossils (pollen, spores), and can often give species-level information, especially for past vascular plant and mammal abundances. Time series are much richer in information than contemporary spatial distribution information, which have been traditionally used to train models for predicting biodiversity and ecosystem responses to climate change. Here, we outline the potential contribution of sedaDNA to forecast ecosystem changes. We showcase how species-level time series may allow quantification of the effect of biotic interactions in ecosystem dynamics, and be used to estimate dispersal rates when a dense network of sites is available. By combining palaeo-time series, process-based models, and inverse modelling, we can recover the biotic and abiotic processes underlying ecosystem dynamics, which are traditionally very challenging to characterise. Dynamic models informed by sedaDNA can further be used to extrapolate beyond current dynamics and provide robust forecasts of ecosystem responses to future climate change. This article is part of the theme issue 'Ecological novelty and planetary stewardship: biodiversity dynamics in a transforming biosphere'.

Life before Stonehenge: The hunter-gatherer occupation and environment of Blick Mead revealed by sedaDNA, pollen and spores.

The Neolithic and Bronze Age construction and habitation of the Stonehenge Landscape has been extensively explored in previous research. However, little is known about the scale of pre-Neolithic activity and the extent to which the later monumental complex occupied an 'empty' landscape. There has been a long-running debate as to whether the monumental archaeology of Stonehenge was created in an uninhabited forested landscape or whether it was constructed in an already partly open area of pre-existing significance to late Mesolithic hunter-gatherers. This is of significance to a global discussion about the relationship between incoming farmers and indigenous hunter-gatherer societies that is highly relevant to both Old and New World archaeology. Here we present the results of plant sedaDNA, palynological and geoarchaeological analysis at the Late hunter-gatherer site complex of Blick Mead at the junction of the drylands of Salisbury Plain and the floodplain of the River Avon, on the edge of the Stonehenge World Heritage Site. The findings are placed within a chronological framework built on OSL, radiocarbon and relative archaeological dating. We show that Blick Mead existed in a clearing in deciduous woodland, exploited by aurochsen, deer and hunter-gatherers for approximately 4000 years. Given its rich archaeology and longevity this strongly supports the arguments of continuity between the Late Mesolithic hunter-gatherers activity and Neolithic monument builders, and more specifically that this was a partially open environment important to both groups. This study also demonstrates that sediments from low-energy floodplains can provide suitable samples for successful environmental assaying using sedaDNA, provided they are supported by secure dating and complementary environmental proxies.

Postglacial species arrival and diversity buildup of northern ecosystems took millennia.

What drives ecosystem buildup, diversity, and stability? We assess species arrival and ecosystem changes across 16 millennia by combining regional-scale plant sedimentary ancient DNA from Fennoscandia with near-complete DNA and trait databases. We show that postglacial arrival time varies within and between plant growth forms. Further, arrival times were mainly predicted by adaptation to temperature, disturbance, and light. Major break points in ecological trait diversity were seen between 13.9 and 10.8 calibrated thousand years before the present (cal ka BP), as well as break point in functional diversity at 12.0 cal ka BP, shifting from a state of ecosystem buildup to a state where most habitat types and biotic ecosystem components were in place. Trait and functional diversity stabilized around 8 cal ka BP, after which both remained stable, although changes in climate took place and species inflow continued. Our ecosystem reconstruction indicates a millennial-scale time phase of formation to reach stable and resilient levels of diversity and functioning.

High resolution ancient sedimentary DNA shows that alpine plant diversity is associated with human land use and climate change.

The European Alps are highly rich in species, but their future may be threatened by ongoing changes in human land use and climate. Here, we reconstructed vegetation, temperature, human impact and livestock over the past ~12,000 years from Lake Sulsseewli, based on sedimentary ancient plant and mammal DNA, pollen, spores, chironomids, and microcharcoal. We assembled a highly-complete local DNA reference library (PhyloAlps, 3923 plant taxa), and used this to obtain an exceptionally rich sedaDNA record of 366 plant taxa. Vegetation mainly responded to climate during the early Holocene, while human activity had an additional influence on vegetation from 6 ka onwards. Land-use shifted from episodic grazing during the Neolithic and Bronze Age to agropastoralism in the Middle Ages. Associated human deforestation allowed the coexistence of plant species typically found at different elevational belts, leading to levels of plant richness that characterise the current high diversity of this region. Our findings indicate a positive association between low intensity agropastoral activities and precipitation with the maintenance of the unique subalpine and alpine plant diversity of the European Alps.

Sedimentary ancient DNA shows terrestrial plant richness continuously increased over the Holocene in northern Fennoscandia.

The effects of climate change on species richness are debated but can be informed by the past. Here, we generated a sedimentary ancient DNA dataset covering 10 lakes and applied novel methods for data harmonization. We assessed the impact of Holocene climate changes and nutrients on terrestrial plant richness in northern Fennoscandia. We find that richness increased steeply during the rapidly warming Early Holocene. In contrast to findings from most pollen studies, we show that richness continued to increase thereafter, although the climate was stable, with richness and the regional species pool only stabilizing during the past three millennia. Furthermore, overall increases in richness were greater in catchments with higher soil nutrient availability. We suggest that richness will increase with ongoing warming, especially at localities with high nutrient availability and assuming that human activity remains low in the region, although lags of millennia may be expected.

European agricultural terraces and lynchets: from archaeological theory to heritage management.

Terraces are highly productive, culturally distinctive socioecological systems. Although they form part of time/place-specific debates, terraces per se have been neglected - fields on slopes or landscape elements. We argue that this is due to mapping and dating problems, and lack of artefacts/ecofacts. However, new techniques can overcome some of these constraints, allowing us to re-engage with theoretical debates around agricultural intensification. Starting from neo-Broserupian propositions, we can engage with the sociopolitical and environmental aspects of terrace emergence, maintenance and abandonment. Non-reductionist avenues include identifying and dating different phases of development within single terrace systems, identifying a full crop-range, and other activities not generally associated with terraces (e.g. metallurgy). The proposition here is that terraces are a multi-facetted investment that includes both intensification and diversification and can occur under a range of social conditions but which constitutes a response to demographic pressure in the face to fluctuating environmental conditions.

A Matador-like Predator Diversion Strategy Driven by Conspicuous Coloration in Guppies.

Understanding the adaptive function of conspicuous coloration has been a major focus of evolutionary biology for much of the last century. Although considerable progress has been made in explaining how conspicuous coloration can be used in functions as diverse as sexual and social signaling, startling predators, and advertising toxicity [1], there remain a multitude of species that display conspicuous coloration that cannot be explained by existing theory. Here we detail a new "matador-like" divertive antipredator strategy based on conspicuous coloration in Trinidadian guppies (Poecilia reticulata). Guppies encountering predatory fish rapidly enhance the conspicuousness of their eyes by blackening their irises. By pitting biomimetic robotic guppies against real predatory fish, we show this conspicuous eye coloration diverts attacks away from the guppies' center of mass to their head. To determine the function of this seemingly counterintuitive behavior, we developed a method for simulating escape probabilities when live prey interact with ballistic attacking predators, and find this diversion effect significantly benefits black-eyed guppies because they evade capture by rapidly pivoting away from the predator once it has committed to its attack. Remarkably, this antipredator strategy reverses the commonly observed negative scaling relationship between prey size and evasive ability, with larger fish benefiting most from diverting predators. Taken together, our results introduce a new antipredator divertive strategy that may be widely used by conspicuously colored prey that rely on agility to escape their predators.

Empathy in preschool children: the development of the Southampton Test of Empathy for Preschoolers (STEP).

In this study, we investigated a new instrument: the Southampton Test of Empathy for Preschoolers (STEP). The test incorporated 8 video vignettes of children in emotional scenarios, assessing a child's ability to understand (STEP-UND) and share (STEP-SHA) in the emotional experience of a story protagonist. Each vignette included 4 emotions (angry, happy, fearful, sad) that reflected emotion judgments based on the protagonist's facial expression, situation, verbal cues, and desire. The STEP was administered to 39 preschool children, and internal reliability, concurrent validity, and construct validity were addressed. The results showed good internal consistency. They also highlighted moderate concurrent validity with parent-rated empathy, a measure of facial indices, and construct validity with teacher-rated prosocial behavior.

Dynamic eye colour as an honest signal of aggression.

Animal eyes are some of the most widely recognisable structures in nature. Due to their salience to predators and prey, most research has focused on how animals hide or camouflage their eyes [1]. However, across all vertebrate Classes, many species actually express brightly coloured or conspicuous eyes, suggesting they may have also evolved a signalling function. Nevertheless, perhaps due to the difficulty with experimentally manipulating eye appearance, very few species beyond humans [2] have been experimentally shown to use eyes as signals [3]. Using staged behavioural trials we show that Trinidadian guppies (Poecilia reticulata), which can rapidly change their iris colour, predominantly express conspicuous eye colouration when performing aggressive behaviours towards smaller conspecifics. Furthermore, using a novel, visually realistic robotic system to create a mismatch between signal and relative competitive ability, we show that eye colour is used to honestly signal aggressive motivation. Specifically, robotic 'cheats' (that is, smaller, less-competitive robotic fish that display aggressive eye colouration when defending a food patch) attracted greater food competition from larger real fish. Our study suggests that eye colour may be an under-appreciated aspect of signalling in animals, shows the utility of our biomimetic robotic system for investigating animal behaviour, and provides experimental evidence that socially mediated costs towards low-quality individuals may maintain the honesty of dynamic colour signals.

The combined use of pollen and soil analyses in a search and subsequent murder investigation.

This case report shows how soil analyses (particularly petrology) can be used in conjunction with pollen in order to refine or strengthen an association. Soil samples from a car believed to have been used by the suspect in a missing persons case was subjected to soil and pollen analyses. The soil characteristics and petrology were used to redefine the search area using geology and soils maps, the pollen and vegetative remains were used to target woodlands with a particular species mix. As a result two bodies were located and the environmental evidence was used in the subsequent trial. In this case the history of the vehicle was well known and the wheel arches and footwells provided reliable soil traps. The advantage of combining the techniques is that soil evidence (both mineralogy and other inclusions) provides a geological/soils match while the pollen provides independent evidence of vegetation type providing a combination that may be rare or unique.

Site distribution at the edge of the palaeolithic world: a nutritional niche approach.

This paper presents data from the English Channel area of Britain and Northern France on the spatial distribution of Lower to early Middle Palaeolithic pre-MIS5 interglacial sites which are used to test the contention that the pattern of the richest sites is a real archaeological distribution and not of taphonomic origin. These sites show a marked concentration in the middle-lower reaches of river valleys with most being upstream of, but close to, estimated interglacial tidal limits. A plant and animal database derived from Middle-Late Pleistocene sites in the region is used to estimate the potentially edible foods and their distribution in the typically undulating landscape of the region. This is then converted into the potential availability of macronutrients (proteins, carbohydrates, fats) and selected micronutrients. The floodplain is shown to be the optimum location in the nutritional landscape (nutriscape). In addition to both absolute and seasonal macronutrient advantages the floodplains could have provided foods rich in key micronutrients, which are linked to better health, the maintenance of fertility and minimization of infant mortality. Such places may have been seen as 'good (or healthy) places' explaining the high number of artefacts accumulated by repeated visitation over long periods of time and possible occupation. The distribution of these sites reflects the richest aquatic and wetland successional habitats along valley floors. Such locations would have provided foods rich in a wide range of nutrients, importantly including those in short supply at these latitudes. When combined with other benefits, the high nutrient diversity made these locations the optimal niche in northwest European mixed temperate woodland environments. It is argued here that the use of these nutritionally advantageous locations as nodal or central points facilitated a healthy variant of the Palaeolithic diet which permitted habitation at the edge of these hominins' range.

Total hip arthroplasty after periacetabular osteotomy.

Patients with hip dysplasia often endure multiple surgical interventions, first in attempts to preserve their biologic hips and later for total hip arthroplasty (THA). Each different surgical approach traumatizes the musculoligamentous complex of the hip. These cumulative insults can significantly affect THA success. We retrospectively reviewed 8 patients who underwent THA after previous periacetabular osteotomy via the same anterior approach. Acetabular bone stock required no augmentation for implant coverage. No complication occurred during surgery. All patients increased their functional score at last follow-up. No dislocation or implant loosening occurred. Leg-length restoration was excellent. Periacetabular osteotomy is a proven conservative procedure in dysplastic hips that can be realized through a Smith-Petersen incision. Restoration of the acetabular anatomy is achieved with limited muscle detachment. Good results have been achieved with periacetabular osteotomy; however, some patients develop increasing pain from progression of osteoarthritis and require a THA to allow relief of symptoms. The anterior-approach THA is a well-established procedure using the same Smith-Petersen interval as periacetabular osteotomy. Using this approach for both procedures optimizes the patient's immediate and ultimate functional recovery and hip stability. Instead of compromising subsequent THA, periacetabular osteotomy may improve THA results in dysplastic hips.